Acknowledgments for DISCovering Science photos and images:

Aardvark: Young aardvark, photograph. Jen and Des Bartlett, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Abacus: Abacus, with Earth and Heaven beads, photograph Courtesy of Gale Research.
Abacus: Abacus, half of abacus with earth and heaven beads, photograph. Courtesy of Gale Research.
Abbe, Cleveland: Abbe, Cleveland, portrait. The Library of Congress.
Abbe, Ernst: Abbe, Ernst, photograph. The Library of Congress.
Abcess: Ameobic abcess, medicine, photograph. © Phototake (CN) /Phototake NYC. Reproduced with permission.
Abel, John Jacob: Abel, John Jacob, portrait. The Library of Congress.
Abel, Niels Henrik: Abel, Niels Henrik, portrait. The Library of Congress.
Accelerators: Mark I detector, photograph. © Lawrence Berkeley Lab, The National Audubon Society Collection/Photo Researchers, Inc.
Accelerators: Accelerators, charged particles. © Alexander Tsiaras, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Accelerators: Accelerators, portrait. The Library of Congress.
Accretion Disk: Cygnus X-1, black hole, phototgraph. © David Hardy/Science Photo Library, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Acid Rain: Acid rain damage, Chicago, photograph. JLM Visuals. Reproduced with permission.
Acidification (Acid rain): Forest, trees, frog, photograph. JLM Visuals. Reproduced with permission.
Acids & bases: Butanedioic acid, micrograph, photograph. © Astrid & Hanns-Frieder Michler/Science Photo Library, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Acne: Acne, young lady, photograph. © Biophoto Associates, Nation Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Acoustics: Acoustics, three figures illustrating acoustics, photograph. Courtesy of Gale Research.
Active galactic nuclei: Black hole, galaxy, photograph. © Mark Marten, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Acupuncture: Acupuncture, photograph. © Yoav Levy /Phototake NYC. Reproduced with permission.
Acupuncture: Acupuncture, side profile of head with pressure points, photograph. Hans & Cassidy. Courtesy of Gale Research.
Adaptation: Cactus plant, desert, photograph. JLM Visuals. Reproduced with permission.
Adaptation: Tall pine, forest, photograph. JLM Visuals. Reproduced with permission.
Addiction: Addiction, two men smoking crack, photograph. © Stock Market. Reproduced with permission.
Adenosine diphosphate: Adenosine diphosphate, chart representing cellular respirartion, photograph. Courtesy of Gale Research.
Adenosine triphosphate: Adenosine triphosphate, photograph. © M.W. Davidson, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Adhesive: Macrophotograph of adhesive, photograph. © Astrid & Hanns-Frieder Michler/Science Photo Library, The National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Adrenals: Cross section of human adenal gland, photograph. © artin M. Rotker/Phototake NYC. Reproduced with permission.
Adrian, Edgar Douglas: Adrian, Edgar Douglas, portrait. The Library of Congress.
Aerobic: Aerobic exercise, phtograph. © Dr. Tony Brain/Science Photo Library, National Audubon Society Colllection/Photo Resarchers, Inc.
Aerodynamics: Wind tunnel, photograph. © Dr. Gary Settles/Science Source, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Aerosol: (c) Chris Rogers, The Stock Market. Reproduced with permission.
Africa: Mount Kilmanjaro, photograph. JLM Visuals. Reproduced with permission.
Africa: Hans & Cassidy. Courtesy of Gale Research.
Africa: Africa, map, photograph. Courtesy of Gale Reaserch.
Agassiz, Jean Louis Rodolphe: Agassiz, Jean Louis Rodolphe, photograph. The Library of Congress.
Aging and death: Aging and death, two women, photograph. Custom Medical Stock Photo, Inc. Reproduced with permission.
Agouti: Agouti on hind legs, photograph. © Roy Pinney, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Agricultural machinery: Big red tractor, photograph. JLM Visuals. Reproduced with permission.
Agricultural machines: Agricultural machines, man plowing, photograph. © Ken Wagner/ Phototake NYC. Reproduced with permission.
Agrochemicals: Orchard sprayer, photograph. © Ken Wagner/Phototake NYC. Reproduced with permission.
Agronomy: Irrigated area, dry area, Iran, photograph. JLM Visuals. Reproduced with permission.
Aids: Mature virus, lymphocyte, photograph. © Scott Camazinr, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Air Pollution: Air pollution, smog over city, photograph. © Tom Carroll/Phototake NYC. Reproduced with permission.
Air pollution: Illustrations reprinted by permission of Robert L. Wolke.
Air pollution: Illustrations reprinted by permission of Robert L. Wolke.
Aircraft: Aircratf, stealth bomber, photograph. U. S. National Aeronautics and Space Administration (NASA).
Aircraft: Soviet Supersonic plane, photograph. U. S. National Aeronautics and Space Administration (NASA).
Aircraft: Voyager aircraft, portrait. The Library of Congress.
Airship: Santos Dumont airship, Paris, photograph. U. S. National Aeronautics and Space Administration (NASA).
Airship: Graf Zeppelin, portrait. The Library of Congress.
Airship: Airship, diagram, photograph. Hans & Cassidy. Courtesy of Gale Research.
Alaska Highway: Alaska Highway, photograph. © E. H. Cobb, U. S. Geological Survey.
Albatrosses: Waved albatross, photograph. JLM Visuals. Reproduced with permission.
Albedo: Albedo, photograph. © P. Carrara,U. S. Geological Survey.
Albinism: Albino negro with father, photograph. © Norman Lightfoot, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Alcohol: Alcohol, six molecular structures of various alcohols, photograph. Hans & Cassidy. Courtesy of Gale Research.
Aldehydes: Silver mirror test for aldehydes, photograph. © Jerry Mason/Science Photo Library, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Alder, Kurt: Alder, Kurt, portrait. The Library of Congress.
Alembert, Jean le Rond d': Alembert, Jean le Rond d', portrait. The Library of Congress.
Alexander, Archie Alphonso: Alexander, Archie Alphonso, (walking), photograph. Library of Congress.
Algae: green algae, photograph. © Rakoey, Alex/Custom Medical Stock Photo, Inc. Reproduced with permission.
Algae: Algae, flow chart, photograph. Hans & Cassidy. Courtesy of Gale Research.
Algal bloom: Ferraris, Greenpeace. Reproduced with permission.
Allergy: Allergy, flow chart, photograph. Hans & Cassidy. Courtesy of Gale Research.
Allergy: Hans & Cassidy. Courtesy of Gale Research.
Alluvial system: Crowsfoot delta, natural levee, photograph. © Dan Guravich, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Alternative energy sources: Wind generators, photograph. JLM Visuals. Reproduced with permission.
Alternative energy sources: Wind mill, photograph. The Library of Congress.
Alternative medicine: Doctor using acupuncture, photograph. Photograph by Charles Gupton. The Stock Market. Reproduced by permission.
Altimeter: Altimeter, balloon, line drawing. Han & Cassidy. Courtesy of Gale Research.
Aluminum: Illustrations reprinted by permission of Robert L. Wolke.
Aluminum: Aluminum, construction, photograph. JLM Visuals. Reproduced with permission.
Alzheimer's disease: Alzheimer's disease, brain tissue. © Cecil Fox/Science Source, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Amaranth: Amaranth, photograph. © Joe Munroe, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Amaranth: Amaranth, photograph. © 1992 Alan L. Detrick, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Amaryllis family: Amaryllis, photograph. © F. Gohier 1982, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Amaryllis family: Amaryllis, photograph. © Verna Johnston 1972, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
American alligator: M. Woodbridge Williams, National Park Service. Reproduced with permission.
Amino acid: Illustration. Robert L. Wolke. Reproduced with permission.
Amino acid: Amino acid, molecular structure of amino acid, photograph. Hans & Cassidy. Courtesy of Gale Research.
Amino acid (glycine): Glycine amino acid, computer graphic, photograph. © Scott Camazine, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Ammonia: Amonia molecule, photograph. © Ken Eward/Science Source, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Ammonification: Elk carcas, photograph. JLM Visuals. Reproduced with permission.
Amniocentesis: Amneocentesis, pregnant woman, photograph. © Will and Deni McIntyre, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Amphibians: Amphibians, flow chart, tadpole, frog, illustration. Hans & Cassidy. Courtesy of Gale Research.
Amplifier: Anteres fusion laser power amplifier, photograph. © Ray Nelson/PhototakeáNYC. Reproduced with permission.
Andersen, Dorothy: Andersen, Dorothy, portrait. The Library of Congress.
Anderson, Carl David: Anderson, Carl David, photograph. The Library of Congress.
Anesthesia: Ether, anaesthetic, photograph. © Jean-Loup Charmet, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Aneurism: Brain aneurism, photograph. © CNRI, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Aneurism: Aneurism, human brain, photograph. © Martin Rotker/Phototake NYC Reproduced with permission.
Angiography: Angiogram, coronary artery, photograph. © CNRI /Phototake NYC Reproduced with permission.
Angioplasty, balloon: Angioplasty balloon, photograph. © Will & Deni McIntyre, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Angioplasty, balloon: Angioplasty, balloon, line drawing. Hans & Cassidy. Courtesy of Gale Research.
Anglerfish: Angelrfish, photograph. JLM Visuals. Reproduced with permission.
Animal breeding: Cows, photograph. JLM Visuals. Reproduced with permission.
Anoles: Robert J. Huffman/Field Mark Publications. Reproduced with permission.
Antarctica: Glacier System, Antarctica, photograph. JLM Visuals. Reproduced by permission.
Antarctica: Hans & Cassidy. Courtesy of Gale Research.
Antartica: Antartica, map, photograph. Hans&Cassidy. Courtesy of Gale Research.
Anteater: Robert J. Huffman/Field Mark Publications. Reproduced with permission.
Antelopes and gazelles: Damaliscus Korrigon, photograph. © WM. J. Jahoda, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Antenna: Dopplar radar, photograph. Stock Market. Reproduced with permission.
Antibiotics: Penicillin culture. © McCarthy, T./ Custom Medical Stock Photo, Inc. Reproduced by permission.
Antibody and antigen: Antibody and antigen, two moleculer structures, photograph. Hans & Cassidy. Courtesy of Gale Research.
Antibody and Antigen: Antibody and antigen, molecular structure, photograph. Hans & Cassidy. Courtesy of Gale Research.
Antimony: Antimony, photograph. © Russ Lappa/Science Source, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Antisepsis:
Aphids: Peach aphid, photograph. © Dr. Jeremy Burgess/Science Photo Library, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Apollo 11, Spacecraft: Apollo 11 launch, photograph. U. S. National Aeronautics and Space Administration.
Appleton, Edward: Appleton, Edward, portrait. The Library of Congress.
Apraxia: Apraxia, brain, photograph. Hans & Cassidy. Courtesy of Gale Research.
Aquatic chemistry: National Center for Atmospheric Research/University Corporation for Atmospheric Research/National Science Foundation 539. Reproduced with permission.
Aqueduct: Roman aqueduct, Nimes, photograph. © John Moss, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Arachnid: Spider, photograph. JLM Visuals. Reproduced with permission.
Arachnids: Arachnid, web, photograph. JLM Visuals. Reproduced with permission.
Arago, Dominique Francois: Arago, Dominique Francois, portrait. The Library of Congress.
Arapaima: Arapaima gigas, photograph. © Steinhart Aquarium, Tom McHugh, Photo Researchers, Inc. Reproduced with permission
Arc: Hans & Cassidy. Arc, photograph. Courtesy of Gale Research.
Arch: Arch, line drawing. Courtesy of Gale Research.
Archaeology: Archaeological excavation, photograph. © Tom Bean/Stock Market. Reproduced with permissions.
Archaeology: Archeology, Montezuma castle, photograph. © Tom Bean/Stock Market. Reproduced with permission.
Archaeometallurgy: Research and Conservation Department, Florida Bureau of Archaeology. Reproduced with permission.
Archaeometallurgy: Research and Conservation Department, Florida Bureau of Archaeology. Reproduced with permission.
Archimedes: Archimedes, portrait. The Library of Congress.
Archimedes
Aristotle: Aristotle, portrait. The Library of Congress.
Armadillo: Robert J. Huffman/Field Mark Publications. Reproduced with permission.
Armstrong, Edwin Howard: Armstrong, Edwin Howard, portrait. The Library of Congress.
Arrhenius, Svante August: Arrhenius, Svante August, portrait. The Library of Congress.
Arrow worms: Arrow worm , diagram, photograph. Hans & Cassidy. Courtesy of Gale Research.
Arrowroot: Arrowroot leaves on branch, photograph. © John Dudak/Phototake NYC. Reproduced with permission.
Arteriosclerosis: Carotid artery, photograph. © Alfred Pateka/CNRI/Science Photo Library, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Arteriosclerosis: Arteriosclerosis, flow chart, photograph. Hans & Cassidy. Courtesy of Gale Research.
Arthritis: Arthritis, deformed hand, photograph. © Science Photo Library, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Arthritis: Arthritits, four illustrations of bone joints, photograph. Hans & Cassidy. Courtesy of Gale Research.
Arthropods: Chewing louse, photograph. JLM Visuals. Reproduced with permission.
Artifical fibers: Textiles, artificile fibers, photograph. Ted Horowitz/Stock Market. Reproduced with permission.
Artificial Fibers: Micrograph, polyester fibers., photograph. © Science Photo Library/National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Artificial Heart: Surgery, artificial heart, photograph. © NIH, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Arum family: Arum family, jack in pulpit, photograph. © Ted Keane, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Arum family: Arum family, skunk cabbage, photograph. © Roy Pinney, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Asbestos: JLM Visuals. Reproduced with permission.
Asexual reproduction: Salmonella cell dividing, asexual reproduction, photograph. © Dr. Kari Lounatimaa/ Science Photo Library, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Asexual reproduction: Asexual reproduction, phases of mitosis, illustration. Hans & Cassidy. Courtesy of Gale Research.
Asia: Hans & Cassidy. Courtesy of Gale Research.
Assembly Line: Assembly line robot manufacturing Renault, France, photograph. © Cecilia Posada/Phototake NYC. Reproduced with permission.
Assimilative capacity: Assimilative capacity. Jill Beaumeister/Courtesy of U. S. Forest Service.
AST 1270: Torquetum, portrait. The Library of Congress.
AST 1270: Azimuth, portrait. The Library of Congress.
AST 1576: Cassiopeia constellation , portrait. The Library of Congress.
AST 1731: Hadley's sextant, portrait. The Library of Congress.
AST 1758: Halley's comet, portrait. The Library of Congress.
AST 1847: Mitchell, Maria , photograph. The Library of Congress.
AST 1888: Lick Observatory, portrait. The Library of Congress.
AST 1888: Lick Observatory, portrait. The Library of Congress.
Asthma: Hans & Cassidy. Courtesy of Gale Research.
Aston, Francis W.: Aston, Francis W., portrait. The Library of Congress.
Astroblemes: Large meteor crater, photograph. JLM Visuals. Reproduced with permission.
Astrolabe: Galileo's astrolab, photograph. © Archive, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Astrometry: Hubble Space Telescope, photograph. © NASA/ Mark Marten, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Astronauts: Tereshkova, Valentina, photograph. The Library of Congress.
Astronomists: Hubble, Edwin, photograph. The Library of Congress.
Astronomists: Kepler, Johannes, photograph of painting. The Library of Congress.
Astronomy: Astronomical device, portrait. The Library of Congress.
Astrophysics: Cartwheel galaxy, photograph. © Space Telescope Science Institute/ NASA/Science Photo Library, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Atmosphere, composition and structure of: Atmosphoer, line drawing. Hans & Cassidy. Courtesy of Gale Research.
Atmospheric circulation: Atmospheric circulation, photograph. National Center for Atmospheric Research/University Corporation for Atmospheric Research/National Science Foundation 532. Reproduced with permission.
Atmospheric observation: Atmospheric observation, photograph. National Center for Atmospheric Research/University Corporation for Atmospheric Research/National Science Foundation 221. Reproduced with permission.
Atmospheric Optical Phenomena: Sunset, sun dogs, frozen sea, photograph. © Dan Guravich 1987, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Atmospheric temperature: Satellite map of surface temperature, photograph. © Nasa/Science Photo Library, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Atmospheric temperature: Atmospheric temperature, graph, photograph. Hans & Cassidy. Courtesy of Gale Research.
Atmospheric temperature: Atmospheric temperature, graph of latitude and altitude, illustration. Hans & Cassidy. Courtesy of Gale Research.
Atmospheric temperature: Atmospheric temperature, graph, photograph. Hans & Cassidy. Courtesy of Gale Research.
Atom: Neon atom, computer generated model, photograph. © Kenneth Eward/BioGrafx, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Atomic bomb: Atomic bomb, portrait. The Library of Congress.
Atomic bombs: Atomic bombs, photograph. The Library of Congress.
Atomic Clock: Atomic clock, repairs, photograph. © Royal Greenwhich Observatory, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Atomic force microscope: Atomic force micrograph, photograph. © Philippe Plailly, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Atomic spectroscopy: Atomic spectroscopy, illustration of electrons during, photograph. Hans & Cassidy. Courtesy of Gale Research.
Atomic theory: Atomic theory, five circular illustrations, illustration. Hans & Cassidy. Courtesy of Gale Research.
Atomic theory: Three illustration of atomic theory, photograph. Hans & Cassidy. Courtesy of Gale Research.
Atoms: Illustration. Robert L. Wolke. Reproduced with permission.
Auk: Razorbills, rock, photograph. © Eric Hosking, F.R.P.S., National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Auroras: Northern lights display, photograph. © Pekka Parviatnen, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Australia: Australia, Mountains, photograph. JLM Visuals. Reproduced with permission.
Australia: Hans & Cassidy. Courtesy of Gale Research.
Australia: Hans & Cassidy. Courtesy of Gale Research.
Authors: Thoreau, Henry David (head and shoulders), drawing. The Library of Congress.
Automation: Large robotic machinery, photograph © Robert Essel/Stock Market. Reproduced with permission.
Automobile
Aye-aye: Aye-aye, photograph. © National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Baboon: Yellow baboon, photograph. © Malcolm Boulton, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Bacteria: Bacteria, microscopic image, photograph. JLM Visuals. Reproduced with permission.
Bacteria: Bacteria, diagram, phtograph. Hans & Cassidy. Courtesy of Gale Research.
Bacteriophage: Bacteriophage E-4, attacking Ecoli, photograph. © Lee D. Simon, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Bactian Camel: Camel, desert, photograph. © Paolo Koch , National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission
Badger: Badger, den hole, photograph. © Len Rue Jr., National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Baer, Karl Ernst von: Baer, Karl Ernst von, portrait. The Library of Congress.
Baeyer, Johann Friedrich Wilhelm Adolf von: Baeyer, Johann Friedrich Wilhelm Adolf von, portrait. The Library of Congress.
Bald eagle: Illustration. Robert J. Huffman/Field Mark Publications. Reproduced with permission.
Bald Eagle: Bald eagles, photograph. © Vince Streano/Stock Market. Reproduced with permission.
Baldwin, Matthias: Baldwin, Matthias, portrait. The Library of Congress.
Balloon: Telescope, stratoscope II, photograph. U. S. National Aeronautics and Space Administration (NASA).
Balloon: Telescope, stratoscope II, photograph. U. S. National Aeronautics and Space Administration (NASA).
Balloon: Hot air balloon, photograph. © Paul Logsdon/Phototake NYC. Reproduced with permission.
Banana: Banana tree, photograph. © Irene Vandermolen, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Bandicoot: Cape York Bandicoot, Australia, photograph. © Jen and Des Bartlett, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Banting, Frederick G.: Banting, Frederick G., photograph. The Library of Congress.
Bar code: © Hammond Incorporated, Maplewood, New Jersey. Reproduced with permission.
Bar code: Bar code, line drawing. Hans & Cassidy. Courtesy of Gale Research.
Baranay, Robert: Baranay, Robert, portrait. The Library of Congress.
Barbiturates: Barbituates, illustration. Robert L. Wolke. Reproduced with permission.
Barkla, Charles Glover: Barkla, Charles Glover, portrait. The Library of Congress.
Barnacles: Goose Barnacles, photograph. JLM Visuals. Reproduced with permission.
Barnard, Christiaan Neethling: Barnard, Christiaan Neethling,áportrait. The Library of Congress.
Barometer: Barometer, photograph. © Diane Kalder/Bilderberg/Stock Market. Reproduced with permission.
Barracuda: Barracuda, photograph. © Ron Church, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Barrier Islands: Barrier Island, photograph. JLM Visuals. Reproduced with permission.
Bass: Bass swimming, photograph. © National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Bats: Bats in tree, photograph. © Don Mason/Stock Market. Reproduced with permission.
Bats: Bumblebee bat. © Bat Conservation International. Reproduced with permission.
Batteries: Collection of batteries, photograph. © Dr. Jeremy Burgess/Science Photo Library, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Battery: Battery, line drawing. Hans & Cassidy. Courtesy of Gale Research.
Battery: Battery, diagram, photograph. Hans&Cassidy. Courtesy of Gale Research.
Bear: Polar bear, photograph. © 1994 Zefa Germany/Stock Market. Reproduced with permission.
Bears: © U.S. Fish & Wildlife Service.
Beaver: Beaver, photograph. © Ron Sanford/Stock Market. Reproduced with permission.
Becquerel, Antoine-Henri: Becquerel, Antoine-Henri, portrait. The Library of Congress.
Bee-eaters: Bird eating a bee, photograph. © E. Hanumantha Rao, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Beech family: Chestnut tree, photograph. © Henry Mayer, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Beech family: Forest of beeches, photograph. © Pierre Berger, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Bees: Robert J. Huffman/Field Mark Publications. Reproduced with permission.
Bees: Beehive on tree, photograph. JLM Visuals. Reproduced with permission.
Beet: Robert J. Huffman/Field Mark Publications. Reproduced with permission.
Beetles: American carrion beetle, photograph. JLM Visuals. Reproduced with permission.
Begonia: Flowers, begonias, photograph. © A. Gurmankin 1987/Phototake NYC. Reproduced with permission.
Behavior: Behavior, bears in water, photograph. © Ron Sanford/Stock Market. Reproduced with permission.
Behring, Emil von: Behring, Emil von, portrait. The Library of Congress.
Bekesy, Georg von: Bekesy, Georg von, portrait. The Library of Congress.
Benz, Karl Friedrich: Benz, Karl Friedrich, portrait. The Library of Congress.
Benzene: Benzene molecule, computer graphic, photograph. © Ken Eward/Science Source, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Bergius, Friedrich: Bergius, Friedrich, portrait. The Library of Congress.
Berliner, Emile: Berliner, Emile, portrait. The Library of Congress.
Bernard, Claude: Bernard, Claude, portrait. The Library of Congress.
Bernoulli's principles: Charles D. Bernoulli's principles, young man blowing paper, photograph. © Charles D. Winters National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Berthelot, Pierre Eugene Marcellin: Berthelot, Pierre Eugene Marcellin, portrait. The Library of Congress.
Bessel, Friedrich: Bessel, Friedrich, portrait. The Library of Congress.
Bessemer, Henry: Bessemer, Henry, portrait. The Library of Congress.
Best, Charles Herbert: Best, Charles Herbert, photograph. The Library of Congress.
Big Bang: Big Bang, aftermath, photograph. © Ludek Pesek/Science Photo Library, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Binary Star: Binary star system, X-Ray, photograph. © Max-Planck-Institut Fur Physik Und Astrophysik, Science Photo Library. Reproduced with permission.
Binary star: Binary star, line drawing. Courtesy of Gale Research.
BIO 1542: Drawings of plants from De historia stirpium, by Leonhart Fuchs, portrait. The Library of Congress.
BIO 1607: Rhinoceros illustration based on an Albrecht Duerer drawing, portrait. The Library of Congress.
BIO 1625: A bee drawing from 17th century, portrait. The Library of Congress.
BIO 1665: Illustration from Robert Hooke's Micrographia, portrait. The Library of Congress.
BIO 1730: Frontispiece from 1904 ed . of John Bartram's Bartram's Garden, portrait. The Library of Congress.
BIO 1730: Illustration from 1904 ed . of Bartram's Garden, by John Bartram, portrait. The Library of Congress.
BIO 1730: Illustration from Jan Swammerdam's Bible of Nature, portrait. The Library of Congress.
BIO 1783: Illustration from 1907 edition of The Chinch Bug by F. M. Webster, portrait. The Library of Congress.
BIO 1803: Illustration from 1803 edition of Flora Boreali-Americana, portrait. The Library of Congress.
BIO 1827: Audubon watercolor of a golden eagle, portrait. The Library of Congress.
BIO 1866: Mendel, Gregor , portrait. The Library of Congress.
BIO 1908: Illustration of insects from U. S. Entomological Commission, portrait. The Library of Congress.
BIO 1914: Color drawing from a 1915 German science text, portrait. The Library of Congress.
BIO 1926: Magnus, Rudolf, portrait. The Library of Congress.
BIO 1928: Penfield, Wilder G., and Mrs., portrait. The Library of Congress.
BIO 1966: Choh-Hao, Li, portrait. The Library of Congress.
Biochemists: Seibert, Florence, photograph. The Library of Congress.
Biochemists: Tiselius, Arne Wilhel Kaurin, photograph. The Library of Congress.
Biochemists, Molecular Biologists: Szent-Gyorgyi, Albert, photograph. The Library of Congress.
Bioenergy: U. S. Department of Energy, Washington DC.
Biological Community: Mount Meadow, mule deer, Big Horn Mountains, photograph. JLM Visuals. Reproduced with permission.
Bioluminescenes: Lightning bug, photograph. © Roy Morsch/Stock Market. Reproduced with permission.
Biomagnification: Biomagnification, picture, photograph. Hans & Cassidy. Courtesy of Gale Research.
Biomass fuel: U. S. Department of Energy, Washington DC.
Biome: Boreal foest, Michigan, photograph. JLM Visuals. Reproduced with permission.
Biome: Turkey, Biome, photograph. JLM Visuals. Reproduced with permission.
Biome: Hans & Cassidy. Biome, chart, photograph. Courtesy of Gale Research.
Biophysicists: Crick, Francis, photograph. The Library of Congress.
Biophysicists: Yalow, Rosalyn S., photograph. The Library of Congress.
Biosphere: Robin Foster, Conservation International. Reproduced with permission.
Biot, Jean Baptiste: Biot, Jean Baptiste, portrait. The Library of Congress.
Biotechnology: Micro injection, foreign genes, photograph. © M. Baret/RAPHU, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Birch: Tall birch tree, photograph. © K. G. Vock/Okapia, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Bird of Paradise: Bird of Paradise, tree branch, photograph. © Tom McHugh, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Bird of paradise: Bird of paradise, Baiyer River Sanctuary, New Guinea © Tom McHugh, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Birdseye, Clarence: Birdseye, Clarence, portrait. The Library of Congress.
Birkeland, Kristian Olaf Bernhard: Birkeland, Kristian Olaf Bernhard, portrait. The Library of Congress.
Birth: Cow, Holstein giving birth, photograph. © Cynthia Matthews/Stock Market. Reproduced with permission.
Birth: Birth, baby's head emerging, photograph. © SIU, National Audubon Society Collection/ Photo Researchers, Inc. Reproduced with permission.
Birth: Birth, womb, baby, photograph. Hans & Cassidy. Courtesy of Gale Research.
Birth: Birth, baby in the womb, illustration. Hans & Cassidy. Courtesy of Gale Research.
Birth: Birth, expulsion of fetus, illustration. Hans & Cassidy. Courtesy of Gale Research.
Birth defects: Club foot, birth defects, photograph. © Science Source, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Bismuth: Bismuth crystals, photograph. © Earl Scott, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Bison: Robert J. Huffman/Field Mark Publications. Reproduced with permission.
Bittern: Bittern, photograph. JLM Visuals. Reproduced with permission.
Bivalves: Bivalves, fish, photograph. Hans & Cassidy. Courtesy of Gale Research.
Black Hole Black Hole, photograph. U.S. National Aeronautics and Space Administration (NASA).
Black, Joseph: Black, Joseph, portrait. The Library of Congress.
Black Rhinoceros: Black rhinoceros, photograph. JLM Visuals. Reproduced with permission.
Blackbirds: photograph. Robert J. Huffman/Field Mark Publications. Reproduced with permission.
Blackbirds: photograph. Robert J. Huffman/Field Mark Publications. Reproduced with permission.
Blanchard, Thomas: Blanchard, Thomas, portrait. The Library of Congress.
Bleriot, Louis: Bleriot, Louis, portrait. The Library of Congress.
Blood: Red blood cells, walls of blood vessel. © Dennis Kunkel/Phototake NYC. Reproduced with permission.
Blood: illustration. Hans & Cassidy. Courtesy of Gale Research.
Blood gas analysis: Blood gas analysis, photograph. © Hank Morgan, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Blue revolution: Fisherman, net of fish, photograph. JLM Visuals. Reproduced with permission.
Bluebird: Mountain bluebird, flying, photograph. © Anthony Mercieca Photo, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Boas: Snake, Boa, photograph. © Stephen Green-Amitage/Stock Market. Reproduced with permission.
Bode, Johann Elert: Bode, Johann Elert, portrait. The Library of Congress.
Bond, chemical: Illustrations. Robert L. Wolke. Reproduced with permission.
Bond, chemical: Illustrations. Robert L. Wolke. Reproduced with permission.
Bond, chemical: Illustrations. Robert L. Wolke. Reproduced with permission.
Boobies and Gannets: Birds, Boobies, photograph. © Anthony Wolff/PhototakeáNYC. Reproduced with permission.
Boolean algebra: Boolean algebra, diagram, illustration. Hans & Cassidy. Courtesy of Gale Research.
Boolean algebra: Boolean algebra, diagram, photograph. Hans & Cassidy. Courtesy of Gale Research.
Boolean algebra: diagram. Hans & Cassidy. Courtesy of Gale Research.
Boolean algebra: diagram. Hans & Cassidy. Courtesy of Gale Research.
Boolean algebra: diagram. Hans & Cassidy. Courtesy of Gale Research.
Bordet, Jules: Bordet, Jules, portrait. The Library of Congress.
Boussingault, Jean-Baptiste Joseph: Boussingault, Jean-Baptiste Joseph Diellonne, portrait. The Library of Congress.
Bowerbird: Satin bowerbird, photograph. © Tom McHugh, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Boxfish: Male Pacific boxfish. © Fred McConnaughey, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Boyle, Robert: Boyle, Robert, photograph of painting. The Library of Congress.
Brachiopods: Brachiopod, diagram, photograph. Hans & Cassidy. Courtesy of Gale Research.
Brackish: Salt marsh, low tide NJ, photograph. JLM Visuals. Reproduced with permission.
Bragg, William Henry: Bragg, William Henry, portrait. The Library of Congress.
Brahe, Tycho: Brache, Tycho, photograph of painting. The Library of Congress.
Brain: Brain cells, microscopic image, photograph. © Prof. P. Motta/Dept. of Anatomy/University La Sapienza, Rome/Science Photo Library, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Brain: Brain, diagram, illustration. Hans & Cassidy. Courtesy of Gale Research.
Brattain, Walter Houser: Brattain, Walter Houser, portrait. The Library of Congress.
Brewing: Brewery, Dominican Republic, photograph. © John Olson/Stock Market. Reproduced with permission.
Brewster, David: Brewster, David, portrait. The Library of Congress.
Brick: Flat bed truck, bricks, photograph. JLM Visuals. Reproduced with permission.
Bridge: Bridge, Arizona, photograph. JLM Visuals. Reproduced with permission.
Bridge: Construction of bridge, Dame Point, photograph © Tom Carroll/Phototake NYC. Reproduced with permission.
Bridgman, Percy Williams: Bridgman, Pe rcy Williams, portrait. The Library of Congress.
Bromeliad: Spanish moss, photograph. © Maurice & Sally Landre, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Bromeliad: Moss, bromeliad, photograph. © Jack Dermid 1979, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Bromine: Vessel of bromine. © Charles D. Winters, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Brown pelican: photograph. Robert J. Huffman/Field Mark Publications. Reproduced with permission.
Brown Pelican: Brown pelican, tree bark, photograph. JLM Visuals. Reproduced with permission.
Brown, Robert: Brown, Robert, portrait. The Library of Congress.
Bruce, David: Bruce, David, portrait. The Library of Congress.
Brunel, Isambard Kingdom: Brunel, Isambard Kingdom, portrait. The Library of Congress.
Bubonic Plague: Burning houses, bubonic plague, photograph. © St Bartholomew’s Hospital, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Buckland, William: Buckland, William, portrait. The Library of Congress.
Buckminsterfullerene: Chemical molecule, photograph. © J. Bernholc et al, North Carolina State University/Science Photo Library, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Buckwheat: White buckwheat, photograph. © John Kaprielian, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Buds and budding: Bacteria, budding hydra, photograph. © James Bell, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Building design/architecture: Contemporary architecture, photograph. JLM Visuals. Reproduced with permission.
Bunsen burner: Bunsen burner, photograph. © Yoav Levy/Phototake NYC. Reproduced with permission.
Bunsen, Robert: Bunsen, Robert, portrait. The Library of Congress.
Buoyancy: Man floating on back, water, photograph. JLM Visuals. Reproduced with permission.
Buoyancy: Principle of buoyancy. Hans & Cassidy. Courtesy of Gale Research.
Burbank, Luther: Burbank, Luther, portrait. The Library of Congress.
Burn: Burn, photograph. © Ann Chawatsky/Phototake. Reproduced with permission.
Bustard: Bustard in rift valley, photograph. © Mark Boulton, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Buttercup: Buttercups, photograph. © John Buitenkant 1993, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Butterflies: Butterflies, photograph. Robert J. Huffman/Field Mark Publications. Reproduced with permission.
Butterflies: Butterflies, flow chart, life stages, illustration. Hans & Cassidy. Courtesy of Gale Research.
Butterflies: Butterflies, illustration. Hans & Cassidy. Courtesy of Gale Research.
Butterfly fish: Butterfly fish, photograph. JLM Visuals. Reproduced with permission.
Buzzard: Common buzzard, photograph. © H. Reinhard/Okapia, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Cactus: Cactus, photograph. Robert J. Huffman/Field Mark Publications. Reproduced with permission.
Cactus: Cactus, photograph. Robert J. Huffman/Field Mark Publications.Reproduced with permission.
CAD/CAM: Computer CAD/CAM, photograph. © Ed Kashi/Phototake NYC. Reproduced with permission.
Caddisflies: Caddisflies, life stages, illustration. Hans & Cassidy. Courtesy of Gale Research.
Cadmium: Cadmium metal, photograph. © Rich Treptow, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Caffeine: Photograph. © Phillip A. Harrington, The Stock Market. Reproduced with permission.
Calcium carbonate: White cliffs, Dover, photograph. JLM Visuals. Reproduced with permission.
Calculator: Old and new calculators, photograph. © Doug Handel/Stock Market. Reproduced with permission.
Calculator: Calculator, babylonian digits, illustration. Hans & Cassidy. Courtesy of Gale Research.
Calculus: Calculus, graph approximating line segment, photograph. Hans & Cassidy. Courtesy of Gale Research.
Calculus: Calculus, graph, photograph. Hans & Cassidy. Courtesy of Gale Research.
California condor: Condor, photograph. © U.S. Fish & Wildlife Service.
Caliper: Caliper, measuring fat content, photograph. © Craig Hammell/Bikderberg Stock Market. Reproduced with permission.
Calorimetry: Calorimetry, illustration. Robert L. Wolke. Reproduced with permission.
Calorimetry: Calorimetry, glass of water, stirrer, thermometer photograph. Hans & Cassidy. Courtesy of Gale Research.
Calorimetry: Calorimetry, control panel, stirrer, photograph. Hans & Cassidy. Courtesy of Gale Research.
Calorimetry: Calorimetry, gerbil, photograph. Hans & Cassidy. Courtesy of Gale Research.
Calvin, Melvin: Calvin, Melvin, photograph. The Library of Congress.
Camels: Dromedary camel feeding, photograph. © Leonard Lee Rue, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Camels: Camel, photograph. JLM Visuals. Reproduced with permission.
Canal: Panama Canal, photograph. © Will & Demi McIntyre, National Audubon Society Collection/Photo Researchers, Inc. Reproduced by permission.
Canal: Canal boat, Netherlands, photograph. © Porterfield/Chickering, The National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Canal: Canal, line drawing. Courtesy of Gale Research.
Cancer: Cancer, micrograph, sarcona, photograph. © Dr. Brian Eyden, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Canines: Two hunting dingos, photograph. © Tom McHugh, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Canines: Canines, photograph. © U.S. Fish & Wildlife Service.
Capacitor: Electric fields, capacitor, photograph. © Yoav Levy/ Phototake NYC Reproduced with permission.
Captive breeding and reintroduction: Black-footed ferret, photograph. © Alan D. Carey, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Capuchin monkeys: White-fronted capuchin, photograph. © Renee Lynn, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Capybara: Capybara, photograph. Robert J. Huffman/Field Mark Publications. Reproduced with permission.
Carbohydrate: Fructose molecule, computer diagram, photograph. © Chemical Design Ltd./Science Photo Library, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Carbon: Carbon, illustration. Robert L. Wolke. Reproduced with permission.
Carbon: Carbon, illustration. Robert L. Wolke. Reproduced with permission.
Carbon: Carbon, illustration. Robert L. Wolke. Reproduced with permission.
Carbon: Gems, diamond raw form, photograph. © Rick Gayle/Stock Market. Reproduced with permission.
Carbon cycle: Carbon cycle ,outdoors, illustration. Hans & Cassidy. Courtesy of Gale Research.
Carbon dioxide: Jar containing dry ice, carbon dioxide, photograph. © R. Folwell, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Carbon monoxide: Carbon monoxide, graph, effects under exposure, illustration. Hans & Cassidy. Courtesy of Gale Research.
Cardano, Girolamo: Cardano, Girolamo, portrait. The Library of Congress.
Cardinals and grosbeaks: Cardinals and grosbeaks, photograph. Robert J. Huffman/Field Mark Publications. Reproduced with permission.
Cardinals and grosbeaks: Cardinal, R. Cardinalus, photograph. JLM Visuals. Reproduced with permission.
Caribou: Caribou standing in forest, photograph. © Karl H. Maslowski, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Carnivore: Lion, photograph. JLM Visuals. Reproduced with permission.
Carnivorous plants: plant, photograph. Robert J. Huffman/Field Mark Publications. Reproduced with permission.
Carnivorous plants: plant, photograph. Robert J. Huffman/Field Mark Publications. Reproduced with permission.
Carnivorous plants: Venus flytrap, photograph. © Jerome Wexler 1981, National Audubon Society Collection/Photo Researchers Inc. Reproduced with permission.
Carnot, Nicolas-Leonard Sadi: Carnot, Nicolas-Leonard Sadi, portrait. The Library of Congress.
Carp: Carp, aqaurium, photograph. © Y. Lanceau Jacana, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Carrel, Alexis: Carrel, Alexis, portrait. The Library of Congress.
Carrot family: Cow parsnip and beach rose, photograph. © Mary M. Thatcher, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Carrot family: Carrot plant, leaves, photograph. © Hans Reinhard/Okapia 1990, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Carrying capacity: Carrying capacity. Courtesy of U. S. Forest Service.
Cartesian Coordinate Plane: Cartesian plane, line graph, photograph. Hans & Cassidy. Courtesy of Gale Research.
Cartesian Coordinate Plane: Cartesian Plane, graph, illustration. Hans & Cassidy. Courtesy of Gale Research.
Cartesian Coordinate Plane: Cartesian coordinate plane, graph, illustration. Hans & Cassidy. Courtesy of Gale Research.
Cartesian Coordinate Plane: Cartesian Plane, graph with triangle, photograph. Hans & Cassidy. Courtesy of Gale Research.
Cartography: Cartography, photograph. © M. R. Klepper/U. S. Geological Survey Photographic Library Denver, CO.
Cartwright, Edmund: Cartwright, Edmund, portrait. The Library of Congress.
Carver, George Washington: Carver, George Washington, portrait. The Library of Congress.
Cashew family: Cashew family, poison ivy, photograph. © Carolina Biological Supply/Phototake NYC. Reproduced with permission.
Cashew family: Pistachio tree, photograph. © Holt Studios International, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
CAT Scan: X-Rays, CAT scan, photograph. © Joseph Nettis, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Catfish: Brown Bullhead, photograph. JLM Visuals. Reproduced with permission.
Catheters: Cardiac catheterization, photograph. © Simon Fraser/Freeman Hospital, Newcastle-Upon-Tyne/Science Photo Library, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Cathode ray tube: Cathode ray tube, portrait. The Library of Congress.
Cats: Cats, Lynx, photograph. © Thomas H. Brakerfield/Stock Market. Reproduced with permission.
Cats: Two cheetahs, photograph. © Masud Quraishy, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Cattails: Cattails in field, photograph. © C. G. Maxwell, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Cattle: Water Buffalo, photograph. © George Turner, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Cattle Family: Longhorn cattle, photograph. JLM Visuals. Reproduced with permission.
Cauchy, Augustin-Louis: Cauchy, Augustin-Louis, portrait. The Library of Congress.
Cauterization: Birthmark cauterization, photograph. © Alexander Tsiaras, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Cave: Natural entrance, cave, photograph. JLM Visuals. Reproduced with permission.
Cavendish, Henry: Cavendish, Henry, photograph of painting. The Library of Congress.
Caves: Caves, stalactities and stalacmites, photograph. © Pedro Coll/Stock Market. Reproduced with permission.
Cayley, Arthur: Cayley, Arthur, portrait. The Library of Congress.
Celestial Coordinates: Polar equatorial star trails, photograph. JLM Visuals. Reproduced with permission.
Celestial Mechanics: Satellite, space mechanics, photograph. © Frank Rossotto/Stock Market. Reproduced with permission.
Cell: The living cell, photograph. © Fawcett, National Audubon Society Collection/ Photo Researchers, Inc. Reproduced with permission.
Cell: Cell, large diagram, photograph. Hans & Cassidy. Courtesy of Gale Research.
Cellulose: Cellulose, two diagrams, photograph. Hans & Cassidy. Courtesy of Gale Research.
Centipedes: Centipedes, photograph. JLM Visuals. Reproduced with permission.
Centrifuge: Centrifuge, phootograph. © Charles D. Winters, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
CERCLA: CERCLA, photograph. Robert Visser, Greenpeace. Reproduced with permission.
Cetaceans: Atlantic bottle-nose dolphin, photograph. JLM Visuals. Reproduced with permission.
Chain, Ernst Boris: Chain, Ernst Boris, photograph. The Library of Congress.
Chamberlain, Owen: Chamberlain, Owen, portrait. The Library of Congress.
Chameleon: Chameleon, photograph. JLM Visuals. Reproduced with permission.
Chaos: Dipolar vortices, collision, photograph. © G. Van Heijst and J. Flor, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Charles, Jacques-Alexandre-Cesar: Charles, Jacques-Alexandre-Cesar, portrait. The Library of Congress.
CHE 1100: 13th century Greek machines, portrait. The Library of Congress.
CHE 1540: Illustration of technique for separating metals from ores, portrait. The Library of Congress.
CHE 1548: Palissy crockery, photograph. The Library of Congress.
CHE 1548: Palissy crockery, photograph. The Library of Congress.
CHE 1548: Palissy the Huguenot Potter, photograph. The Library of Congress.
CHE 1669: Becher, Johann Joachim, photograph. The Library of Congress.
CHE 1669: German chemists, photograph. The Library of Congress.
CHE 1740: Primitive English chemistry lab, photograph. The Library of Congress.
CHE 1765: Scheelf, Karl Wilhelm, photograph. The Library of Congress.
CHE 1782: Instruments from Lavoisier's lab, photograph. The Library of Congress.
CHE 1782: Lavoisier, portrait. The Library of Congress.
CHE 1815: De Changy electric lamp for miners, photograph. The Library of Congress.
CHE 1823: 19th century chemistry lecture, photograph. The Library of Congress.
CHE 1823: Faraday, Michael, portrait. The Library of Congress.
CHE 1836: Constant battery, photograph. The Library of Congress.
CHE 1841: Chemical Society of London members, 1841, photograph. The Library of Congress.
CHE 1843: Chemical Society of London members, photograph. The Library of Congress.
CHE 1855: 19th century Bunsen burner, photograph. The Library of Congress.
CHE 1866: Rendition of benzol, photograph. The Library of Congress.
CHE 1869: Early Periodic Table, photograph. The Library of Congress.
CHE 1869: Manufacture of celluloid, photograph. The Library of Congress.
CHE 1911: Cellophane, photograph. The Library of Congress.
CHE 1911: Constitution of matter, photograph. The Library of Congress.
CHE 1913: Stainless steel cutlery, photograph. The Library of Congress.
CHE 1921: Midgley, Thomas Jr., portrait. The Library of Congress.
CHE 1934: Beckman, Arnold O., portrait
CHE 1940: Kamen, Martin D., portrait. The Library of Congress.
CHE 1952: Waksman, Selman A., portrait. The Library of Congress.
CHE 1954: Salk, Jonas, portrait. The Library of Congress.
CHE 1957: Bovet, Daniel, portrait. The Library of Congress.
CHE 775: Geber, portrait. The Library of Congress.
Cheetah: Cheetah, photograph. Robert J. Huffman/Field Mark Publications. Reproduced with permission.
Chemical Warfare: Chemical warfare. © The Bettman Archive. Reproduced with permission.
Chemistry: Molecular graphics, photograph. © Ken Eward/BioGrafx/Science Source, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Chemistry: Chemistry, photograph. The Library of Congress.
Chemists: Davy, Humphry, photograph. The Library of Congress.
Chemists: Todd, Alexander Robertus, photograph. The Library of Congress.
Chemists, Microbiologists: Brown, Rachel Fuller and Elizabeth Lee Hazen, photograph. The Library of Congress.
Chemists, Physicists: Curie, Marie, photograph. The Library of Congress.
Chemists, Physicists: Curie, Pierre, photograph of painting. The Library of Congress.
Chemists, Physicists: Dalton, John, photograph of painting. The Library of Congress.
Chemists, Physicists: Faraday, Michael, photograph of sketch. The Library of Congress.
Chemists, Scientists: Langmuir, Irving, photograph. The Library of Congress.
Chemists, Scientists: Lavoisier, Antoine-Laurent, photograph. The Library of Congress.
Chemoreception: Chemoreception, photograph. © Carolina Biological Supp/Phototake NYC. Reproduced with permission.
Cherenkov, Pavel A.: Cherenkov, Pavel A., portrait. The Library of Congress.
Chevreul, Michel Eugene: Chevreul, Michel Eugene, portrait. The Library of Congress.
Chicken pox: Chicken pox, young girl, photograph. © Jim Selby/Science Photo Library, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Chimpanzee: Gorillas, photograph. © Kennan Ward/Stock Market. Reproduced with permission.
Chinchilla: Chinchilla, photograph. © National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Chipmunk: Chipmunk, photograph. JLM Visuals. Reproduced with permission.
Chlorine: Chemical reaction, sodium, chlorine, photograph. © Yoav Levy/Phototake NYC Reproduced with permission.
Chloroplast: Tobacco leaf chloroplast, micrograph, photograph. © Dr. Jeremy Burgess/Science Photo Library, National Audubon Society Collection/ Photo Researchers, Inc. Reproduced with permission.
Chocolate: Chocolate, line drawing. Courtesy of Gale Research.
Chocolate: Chocolate, chart, formed into chocolate bar, photograph. Hans & Cassidy. Courtesy of Gale Research.
Cholera: Vibrio Cholreae, choler, photograph. © McCarthy, T./ Custom Medical Stock Photo, Inc. Reproduced with permission.
Cholesterol: Monohydrate cholesterol crystals, photograph. © Dr. Jeremy Burgess/Science Photo Library, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Chromatography: Man with pharmaceutical machinery, photograph. © Simon Fraser/Searle Pharmaceuticals, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Chromium: Chemistry, chromium, photograph. © Yoav Levy/Phototake NYC Reproduced with permission.
Chromosomal abnormalities: Chromosomal abnormalities, two diagrams, illustration. Hans & Cassidy. Courtesy of Gale Research.
Chromosomal abnormalities: Chromosomal abnormalities, "X" and "Y" combinations, illustration. Hans & Cassidy. Courtesy of Gale Research.
Chromosomal abnormalities: Chromosomal abnormalities, chart, photograph. Hans & Cassidy. Courtesy of Gale Research.
Chromosome: X-chromosomes, reproductive chromosomes, photograph. © Biophoto Associates, National Audubon Society Collection/ Photo Researchers, Inc. Reproduced with permission.
Chromosome: Chromosome abnormalities, box with chromosomes, photograph. Hans & Cassidy. Courtesy of Gale Research.
Chromosome: Chromosome, illustrations, illustration. Hans & Cassidy. Courtesy of Gale Research.
Cicada: Cicada, human hand, photoograph. © Jen and Des Bartlett, National Aububon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Cigarette Smoke: Smoker's lung, normal lung, comparison, photograph. © A. Glauberman, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Circulatory system: Circulatory system, photograph. © Stock Market. Reproduced with permission.
Circulatory system: Circulatory system, line drawing. Hans & Cassidy. Courtesy of Gale Research.
Cirrhosis: Micrograph of liver cirrhosis, photograph. © Prof. P. Motta/Dept. of Anatomy/University of "La Sapienza", Rome/Science Photo Library, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
CITES: CITES, photograph. Haroldo Castro, Conservation International. Reproduced with permission.
Citric acid: Microscopic image of citric acid, photograph. © Alfred Pasieka/Science Photo Library, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Citric acid: Citric acid, molecular structure, photograph. Hans & Cassidy. Courtesy of Gale Research.
Citrus tree: Grapefruits, photograph. © 1980 Ken Brate, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Citrus trees: Citrus trees, photograph. © Scott Camazine, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Civets: Banded palm civet, photograph. © Tom McHugh, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Clausius, Rudolf Julius Emmanuel: Clausius, Rudolf Julius Emmanuel, portrait. The Library of Congress.
Clean Air Act: Clean Air Act, photograph. © Robert Visser, Greenpeace. Reproduced with permission.
Clean Water Act: Clean Water Act, photograph. Yuen-Gi Yee/U. S. Forest Service. Reproduced with permission.
Climax (ecological): Climax pine forest, photograph. JLM Visuals. Reproduced with permission.
Clone and cloning: Bannana plants, cloning. © Phillip Hayson, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Closed curves: Closed curves, six shapes, illustration. Hans & Cassidy. Courtesy of Gale Research.
Closed curves: Closed curve, figure eight shape, illustration. Hans & Cassidy. Courtesy of Gale Research.
Closed curves: Closed curve, drawing, illustration. Hans & Cassidy. Courtesy of Gale Research.
Closed curves: Closed curve, swirl, photograph. Hans & Cassidy. Courtesy of Gale Research.
Clouds: Cirrus, cumulus clouds, photograph. © John Deeks, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Clouds: One lane road, corn fields, photograph. JLM Visuals. Reproduced with permission.
Clouds: Clouds on a board. National Oceanic and Atmospheric Administration. Reproduced with permission.
Coal Seam: Coal Seam, CO., photograph. JLM Visuals. Reproduced with permission.
Coast and Beach: Long Island, South Fork, photograph. © Claudia Parks/Stock Market. Reproduced with permission.
Coast and beach: Coast, photograph. Robert J. Huffman/Field Mark Publications. Reproduced with permission.
Coast and Beach: Lake, forest in background, photograph. © Al Greene and Associates, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Coati: Coati, photograph. © Leonard Lee Rue III, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Cobalt: Cobalt, photograph. © Russ Lappa/Science Source, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Coca: Leaves and fruit of coca plant, photograph. © Gregory G. Dimijian 1990, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Cocaine: Cocaine, plant, drugs, photgraph. Hans & Cassidy. Courtesy of Gale Research.
Cockatoos: Bird, cockatoos. © David Woods/Stock Market. Reproduced with permissions.
Cockcroft, John D.: Cockcroft, John D., photograph. The Library of Congress.
Cod: Black cod, photograph. © Zefa Germany/Stock Market. Reproduced with permissions.
Coelacanth: Coelacanth, photograph. © Planet Earth. Reproduced with permissions.
Coffee: Coffee, chart, beans into drink, photograph. Hans&Cassidy. Courtesy of Gale Research.
Coffee plant: Coffee tree, photograph. © Alan D. Carey, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Coffee plant: Coffee plant, line drawing. Hans & Cassidy. Courtesy of Gale Research.
Cogeneration: Cogeneration, photograph. © Robert Visser, Greenpeace. Reproduced with permission.
Cognition: Cognition, children, young boy playing. © Peter Saloutos/Stock Market. Reproduced with permission.
Colloid: Two bottles with light passing through them, photograph. © Charles D. Winters, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Colobus Monkey: Colobus monkey, photograph. © Tim Davis, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Color: Array of bright colors, photograph. © Thierry Cariou/Stock Market. Reproduced with permission.
Colorado River: Grand Canyon, ariel view of Colorado River, photograph. © Jeff Adamo/Stock Market. Reproduced with permission.
Coma: Coma, brain, causes, photograph. Hans & Cassidy. Courtesy of Gale Research.
Coma: Coma, illustration. Hans & Cassidy. Courtesy of Gale Research.
Combine harvester: Combine harvester, line drawing. Hans & Cassidy. Courtesy of Gale Research.
Combine harvester: Combine harvester, line drawing. Hans & Cassidy. Courtesy of Gale Research.
Combine harvester: Combine harvester, diagram of combine harvester, photograph. Hans & Cassidy. Courtesy of Gale Research.
Combustion: Chemistry combustion, photograph. © Yoav Levy/Phototake NYC. Reproduced with permission.
Comet: Comet West, 1976, photograph. U. S. National Aeronautics and Space Administration (NASA).
COMM 1878: Telephone, photograph. The Library of Congress.
COMP 1951: Computers, photograph. The Library of Congress.
Compact disc: Compact disc, photograph. IBM Almaden. Reproduced by permission.
Compass: Compass, line drawing. Hans & Cassidy. Courtesy of Gale Research.
Complex numbers: Complex numbers figure, graph, photograph. Hans & Cassidy. Courtesy of Gale Research.
Complex numbers: Complex numbers figure, acute angle, illustration. Hans & Cassidy. Courtesy of Gale Research.
Composite family: Composite family, photograph. Robert J. Huffman/Field Mark Publications. Reproduced by permission.
Composite family: Two blossoming artichokes, photograph. © 1983 Lawrence Midgale, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Composite family: Composite family, goldenrod flower, photograph. © John Dudak/Phototake NYC. Reproduced with permission.
Composting: Composting, photograph. Robert J. Huffman/Field Mark Publications. Reproduced by permission.
Compound chemical: Compound chemical, photograph. Robert L. Wolke. Reproduced by permission.
Compound chemical: Compound chemical, photograph. Robert L. Wolke. Reproduced by permission.
Compton, Arthur Holly: Compton, Arthur Holly, portrait. The Library of Congress.
Computer, Digital: Bit-serial optical computer, photograph. © David Parker, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Computer, digital: Computer mainframe, portrait. The Library of Congress.
Concrete: Concrete, photograph. Bridge support beams, photograph. David Pollack/Bikderberg, Stock Market. Reproduced with permission.
Concrete: Road construction paving, photograph. © Chris Jones/Stock Market. Reproduced with permission.
Concrete: Concrete, line drawing. Hans & Cassidy. Courtesy of Gale Research.
Concrete: Concrete, line drawing. Hans & Cassidy. Courtesy of Gale Research.
Concrete: Cement, preparing Portland cement, photograph. Hans & Cassidy. Courtesy of Gale Research.
Conditioning: Conditioning, children, photograph. © Elizabeth Hathon/Stock Market. Reproduced with permission.
Condor: California condor, rock, photograph. © Carl Koford, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Congruence (triangle): Congruence figures, triangles, photograph. Hans & Cassidy. Courtesy of Gale Research.
Congruence (triangle): Congruence figures, photograph. Hans & Cassidy. Courtesy of Gale Research.
Congruence (triangle): Congruence figures, ladder, photograph. Hans & Cassidy. Courtesy of Gale Research.
Congruence (triangle): Congruence figure, open triangle, photograph. Hans & Cassidy. Courtesy of Gale Research.
Congruence (triangle): Congruence figure, triangle open at side, photograph. Hans & Cassidy. Courtesy of Gale Research.
Conic sections: Conic section figure, cone, photograph. Hans & Cassidy. Courtesy of Gale Research.
Conic sections: Conic section, cone and circle, photograph. Hans & Cassidy. Courtesy of Gale Research.
Conic sections: Conic sections, cone and oval, photograph. Hans & Cassidy. Courtesy of Gale Research.
Conic sections: Conic sections, cone and arch, photograph. Hans & Cassidy. Courtesy of Gale Research.
Conic sections: Conic sections, photograph. Hans & Cassidy. Courtesy of Gale Research.
Conic sections: Conic sections, diagrams, illustration. Hans & Cassidy. Courtesy of Gale Research.
Conic sections: Conic sections, four large diagrams, photograph. Hans & Cassidy. Courtesy of Gale Research.
Conic sections: Conic sections, line drawing. Hans & Cassidy. Courtesy of Gale Research.
Conic sections: Conic sections, illustration. Hans & Cassidy. Courtesy of Gale Research.
Conic sections: Conic sections, illustration. Hans & Cassidy. Courtesy of Gale Research.
Conic sections: Conic sections, illustration. Hans & Cassidy. Courtesy of Gale Research.
Conic sections: Conic sections, illustration. Hans & Cassidy. Courtesy of Gale Research.
Conifer: Conifer, photograph. Robert J. Huffman/Field Mark Publications. Reproduced by permission.
Conifer: Conifer, photograph. Robert J. Huffman/Field Mark Publications. Reproduced by permission.
Connective tissue: Cartilage, photograph. © Prof. P. Motta/Dept. of Anatomy/University "La Sapienza", Rome/Science Photo Library, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Conservation: Radio collar on elk, photograph. JLM Visuals. Reproduced with permission.
Conservation laws: Conservation laws, two rockets, photograph. Hans & Cassidy. Courtesy of Gale Research.
Conservation laws: Conservation laws, bullet, momentum, photograph. Hans & Cassidy. Courtesy of Gale Research.
Conservation laws: Conservation laws, illustration. Hans & Cassidy. Courtesy of Gale Research.
Constellation: Constellation, Orion, photograph.. U.S. National Aeronautics and Space Administration (NASA).
Constructions: Construction, two merged circles with triangle in the middle, illustration. Hans & Cassidy. Courtesy of Gale Research.
Constructions: Construction, half circle and triangle, photograph. Hans & Cassidy. Courtesy of Gale Research.
Contaminated soil: Contaminated soil, photograph. U. S. Department of Energy, Washington DC.
Contamination: Contamination, photograph. © Neville Gaggiani/U.. S. Geological Survey Photographic Library Denver, CO.
Continental Drift: Continental Drift, illustration. Hans & Cassidy. Courtesy of Gale Research.
Continuity: Continuity, graph. Hans & Cassidy. Courtesy of Gale Research.
Continuity: Continuity, graph, photograph. Hans & Cassidy. Courtesy of Gale Research.
Continuity: Continuity, graph, illustration. Hans & Cassidy. Courtesy of Gale Research.
Continuity: Continuity, graph, photograph. Hans & Cassidy. Courtesy of Gale Research.
Contour Plowing: Contour framing, rice, photograph. © Paul Logsdon/Phototake NYC. Reproduced with permission.
Contraception: Contraceptives, photograph. © Michael Keller/The Stock Market. Reproduced with permission.
Convention on the Prevention of Marine Pollution: Convention on the Prevention of Marine Pollution, photograph. Hewetson, Greenpeace. Reproduced by permission.
Cooper, Peter: Cooper, Peter, portrait. The Library of Congress.
Coordination compound: Coordination compound, three illustrations, photograph. Hans & Cassidy. Courtesy of Gale Research.
Coordination compound: Coordination compound, equation, illustration. Hans & Cassidy. Courtesy of Gale Research.
Coordination compound: Coordination compound, electrons, photograph. Hans & Cassidy. Courtesy of Gale Research.
Coordination compound: Coordination compound,hybridization, photograph. Hans & Cassidy. Courtesy of Gale Research.
Coordination compound: Coordination compound,formation of chelated ring, photograph. Hans & Cassidy. Courtesy of Gale Research.
Coordination compound: Coordination compound, ethylenediamine tetraacetic, photograph. Hans & Cassidy. Courtesy of Gale Research.
Coordination compound: Coordination compound, molecular structure of metallo porphyrin units, photograph. Hans & Cassidy. Courtesy of Gale Research.
Copepoda: Crustacea Copepoda diaptomus, photograph. © M. I. Walker/Science Photo Library, National Audubon Society Collection/Photo Researchers, Inc Reproduced with permission.
Copernicus, Nicholas: Copernicus, Nicholas, photograph. The Library of Congress.
Copper: Copper, photograph. JLM Visuals. Reproduced with permission.
Coral Reef: Belau Kayangel atoll, photograph. © Douglas Faulkner, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Corals: Orange cup coral, photograph. JLM Visuals. Reproduced with permission.
Corals: Corals, diagram of insides, photograph. Hans & Cassidy. Courtesy of Gale Research.
Cori, Carl Ferdinand and Getty T.: Cori, Carl Ferdinand, Cori, Getty T., portrait. The Library of Congress.
Corliss, George Henry: Corliss, George Henry, portrait. The Library of Congress.
Cormorants: Cormorants, photograph. Robert J. Huffman/Field Mark Publications. Reproduced by permission.
Cormorants and Shags: Cormorants and shags, photogrpah. Robert J. Huffman/Field Mark Publications. Reproduced by permission.
Cosmic Rays: Cosmic Ray, photograph. © Prof. D. Skobeltzn, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Cotingas: Cotingas, photograph. © A.W. Ambler , National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Cotton: Cotton, fields, photograph. JLM Visuals. Reproduced with permission.
Cournand, Andre F.: Cournand, Andre F., portrait. The Library of Congress.
Courtship: Courtship, male peacock mating ritual, photograph. © Norbert Wu/Stock Market. Reproduced with permission.
Crab: Hermit crab, photograph. © Thomas Dimock/Stock Market. Reproduced with permissions.
Cram, Donald J.: Cram, Donald J., portrait. The Library of Congress.
Cranes: Bridge, laying decking, photograph. © Holt Confer/Phototake NYC. Reproduced with permission.
Cranes: Cranes, photograph. Robert J. Huffman/Field Mark Publications. Reproduced with permission.
Cranes: Crowned crane, photograph. JLM Visuals. Reproduced with permission.
Cranes: Harbor, Washington Monument, portrait. The Library of Congress.
Crayfish: Crayfish, photograph. Robert J. Huffman/Field Mark Publications. Reproduced with permission.
Cretaceous catastrophe: Cretaceous catastrophe, line drawing. Courtesy of Gale Research.
Crick, Francis: Crick, Francis, photograph. The Library of Congress.
Crocodiles: Crocodiles, photograph. © Planet Earth. Reproduced with permission.
Crocodiles: Tomistoma, photograph. © National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Crompton, Samuel: Crompton, Samuel, portrait. The Library of Congress.
Crop Rotation: Gas well, wheat and rice fields, photograph. JLM Visuals. Reproduced with permission.
Crowned Lemur: Crowned Lemurs, photograph. © National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Crows and jays: Crows and jays, photograph. Robert J. Huffman/Field Mark Publications. Reproduced with permission.
Crustacea: Horseshoe crab, crustacea, photograph. © Diamon T. Smithers, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Cryogenics: Cryotubes, photograph. © Geoff Tompkinson, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Crystal: Crystal, photograph. Robert L. Wolke. Reproduced with permission.
Crystal: Pyrite crystal, photograph. © Joe Bator/Stock Market. Reproduced with permission.
Cuckoos: Roadrunner, photograph. © Allan D. Cruickshank, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Currents: Wave crests, photograph. JLM Visuals. Reproduced with permission.
Curve: Curve, three examples, photograph. Hans & Cassidy. Courtesy of Gale Research.
Cushing, Harvey Williams: Cushing, Harvey Williams, portrait. The Library of Congress.
Cushing's Syndrome: Cushing's syndrome, photograph. © John Radcliff Hospital/Science Photo Library, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Cuttlefish: Cuttlefish, photograph. © Fred McConnaughey, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Cuvier, Georges Leopold: Cuvier, Georges Leopold, photograph. The Library of Congress.
Cycad: Cycad, photograph. JLM Visuals. Reproduced with permission.
Cyclotron: Cyclotron, photograph. © Lawrence Berkeley Laboratory/ Science Photo Library, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Cyclotron: Cyclotron, photograph. The Library of Congress.
Cystic Fibrosis: Cystic Fibrosis, physiotherapist helping young girl, photograph. © Simon Fraser, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Dacron: Dacoron polyester fibers, photograph. © Science Photo Library, The National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Daimler, Gottlieb: Daimler, Gottlieb, portrait. The Library of Congress.
Dam: Hoover Dam, photograph. © Roy Morsch/Stock Market. Reproduced with permission.
Dam: Dam, portrait. The Library of Congress.
Dama Gazelle: Dama Gazelle, photograph. © Mark Newman/Phototake NYC Reproduced with permission.
Damselflies: Damselflies, photograph. Robert J. Huffman/Field Mark Publications. Reproduced by permission.
Damselflies: Damselflies, photograph. © Charles Kreb/Stock Market. Reproduced with permission.
Dark Matter: Dark matter evidence, photograph. U.S. National Aeronautics and Space Administration (NASA).
Dating techniques: Tree growth rings, photograph. © Charles Krebs/Stock Market. Reproduced with permission.
Davisson, Clinton: Davisson, Clinton, portrait. The Library of Congress.
DDT: DDT, photograph. The Library of Congress.
DDT (Dichlorodiphenyl-trichloroacetic): DDT, photograph. © James P. Blair/National Geographic Image Collection. Reproduced by permission.
de Graaf, Regnior: de Graaf, Regnior, portrait. The Library of Congress.
de Vries, Hugo: de Vries, Hugo, (seated with legs crossed), photograph. The Library of Congress.
Debye, Peter: Debye, Peter, portrait. The Library of Congress.
Deer: Deer, photograph. © Robert J. Huffman/Field Mark Publications. Reproduced by permission.
Deer: Deer, photograph. © Tom Brakerfield/Stock Market. Reproduced with permission.
DeForest, Lee: DeForest, Lee, portrait. The Library of Congress.
Deforestation: Jungle erosion, photograph. © Ulrike Welsch, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Delbruck, Max: Delbruck, Max, photograph. The Library of Congress.
Dementia: Coloured positron emission Tomo-acids, photograph. © Dept. of Nuclear Medinice, Charing Cross Hopital, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Democritus: Democritus, portrait. The Library of Congress.
Density: Water density, photograph. © Yoav Levy/ Phototake NYC Reproduced with permission.
Dental drill: Dental drill, photograph. © Randy Duchaine/The Stock Market. Reproduced by permission.
Dentistry: Dentist examining computerized X-rays, phototgraph. © National Institute of Health/Science Photo Library, National Audubon Society Collection/Photo Researchers, Inc. Reproduced by permission.
Dentistry: Denistry, tooths, photograph. Hans & Cassidy. Courtesy of Gale Research.
Deoxyribonucleic Acid (DNA): Structure of the DNA molecule, illustration. Robert L. Wolke. Reproduced by permission.
Deoxyribonucleic acid (DNA): DNA blueprint, photograph. © Phillippe Plailly/Science Photo Library, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Deposits: Large deposite site, photograph. JLM Visuals. Reproduced with permission.
Depression: Two false colored brains, photograph. © NIH/Science Source, National Audubon Society Collection/ Photo Researchers, Inc. Reproduced with permission.
Depth perception: Perception, baby grabbing object, photograph. © Gabe Palmer/Stock Market. Reproduced with permission.
Derivative: Derivitive figure, shaded graph, photograph. Hans & Cassidy. Courtesy of Gale Research.
Derivative: Derivitive figure, graph, upward sloping line, photograph. Hans & Cassidy. Courtesy of Gale Research.
Derivative: Derivitive figure, small graph, three lines, photograph. Hans & Cassidy. Courtesy of Gale Research.
Descartes, Rene: Descartes, Rene, photograph. The Library of Congress.
Desert: Sonoran Desert, Organ Pipe National Monument, photograph. © Robert Jureit/Stock Market. Reproduced with permission.
Desert: Desert, photograph. JLM Visuals. Reproduced with permission.
Desert tortoise: Desert tortoise, photograph. © U.S. Fish & Wildlife Service.
Determinants: Determinants, graph, photograph. Hans & Cassidy. Courtesy of Gale Research.
Determinants: Determinants, graph and equation, illustration. Hans & Cassidy. Courtesy of Gale Research.
Determinants: Determinants, six small boxes, photograph. Hans & Cassidy. Courtesy of Gale Research.
Determinants: Determinants, four small boxes, variables in corners, photograph. Hans & Cassidy. Courtesy of Gale Research.
Dewar, Sir James: Dewar, Sir James, portrait. The Library of Congress.
Diabetes Mellitus: Diabetes mellitus, photograph. © Dr. P. Marazzi/Science Photo Library, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Diagnosis: Diagnosis, doctor examining X-rays, photograph. Photograph by Randy Duchaine. Stock Market. Reproduced with permission.
Dialysis: Man on dialysis machine, photograph. © Giovaux Communication/Phototake NYC Reproduced with permission.
Diels, Otto: Diels, Otto, photograph. The Library of Congress.
Diesel engine: Diesel engine, graph, photograph. Hans & Cassidy. Courtesy of Gale Research.
Diesel engine: Diesel engine, four sketches, illustration. Hans & Cassidy. Courtesy of Gale Research.
Diesel, Rudolf Christian Karl: Diesel, Rudolf Christian Karl, portrait. The Library of Congress.
Diffraction: Color diffraction, photograph. © Peter Angelo Simon/Stock Market. Reproduced with permission.
Diffraction Grating: Circular diffraction pattern, photograph. © James Stevenson, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Diffusion: Carbon dioxide diffusion, photograph. © Andrew Mcclenaghan, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Diffusion: Diffusion, red blood cell, photograph. Hans & Cassidy. Courtesy of Gale Research.
Digestive system: Digestive system, diagram, human, photograph. Hans & Cassidy. Courtesy of Gale Research.
Dik Dik: Dik dik, photograph. © Rapho, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Dinosaur: Dinosaur imprint, photograph. JLM Visual. Reproduced with permission.
Dinosaur: Dinosaur bones, Thailand, photograph. © Bill Wassman/Stock Market. Reproduced with permissions.
Diode: Light enitted diode, photograph. © Yoav Levy/Phototake NYC. Reproduced with permission.
Dioxin: Dioxin, photograph. © Randy Lantz, Greenpeace. Reproduced with permission.
Dioxin: Dioxin, photograph. © Zachary Singer, Greenpeace. Reproduced with permission.
Dipole: Dipole, attraction between two xenon atoms, illustration. Hans & Cassidy. Courtesy of Gale Research.
Dipole: Dipole, molecular shape, illustration. Hans & Cassidy. Courtesy of Gale Research.
Dirac, Paul: Dirac, Paul, photograph of sketch. The Library of Congress.
Discoverers: Newton, Isaac, photograph of the painting. The Library of Congress.
Dissociation: Dissociation, volcano, photograph. © David Taylor, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Dissociation: Dissociation, positive, negative ions, water dipole, photograph. Hans & Cassidy. Courtesy of Gale Research.
Distance: Distance, graph, photograph. Hans & Cassidy. Courtesy of Gale Research.
Distance: Distance, graph with triangle, photograph. Hans & Cassidy. Courtesy of Gale Research.
Distillation: Distillation, apparatus, photograph. Hans & Cassidy. Courtesy of Gale Research.
Distillation: Distillation, illustration. Hans & Cassidy. Courtesy of Gale Research.
Dobzhansky, Theodosius: Dobzhansky, Theodosius, photograph. The Library of Congress.
Dogwood tree: Dogwood tree, photograph. JLM Visuals. Reproduced with permission.
Doisy, Edward A.: Doisy, Edward A., photograph. The Library of Congress.
Domagk, Gerhard: Domagk, Gerhard, portrait. The Library of Congress.
Dome: Cathedral dome, photograph. JLM Visuals. Reproduced with permission.
Dopamine: Dopamine, molecular structure, photograph. Hans & Cassidy. Courtesy of Gale Research.
Dopamine: Dopamine, enlarged pictures, photograph. Hans & Cassidy. Courtesy of Gale Research.
Doppler effect: Doppler effect, train inbetween two stations, illustration. Hans & Cassidy. Courtesy of Gale Research.
Doppler effect: Doppler effect, illstration. Hans & Cassidy. Courtesy of Gale Research.
Dormouse: Dormouse holding branch, photograph. © Jane Burton, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Down's syndrome: Down's syndrom, children, photograph. © Susan Woog Wagner, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Dragonfly: Dragonfly, photograph. © Jeanne White, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Draper, Charles Stark: Draper, Charles Stark, portrait. The Library of Congress.
Driftnet: Driftnet, photograph. © Rowlands, Greenpeace. Reproduced with permission.
Drought: Drought effect, Botswana, photograph. © Tom Nebbia/Stock Market. Reproduced with permission.
du Vigneaud, Vincent: du Vigneaud, Vincent, portrait. The Library of Congress.
Dubois, Eugene: Dubois, Eugene, photograph. The Library of Congress.
Ducks: Ducks, photograph. © Robert J. Huffman/Field Mark Publications. Reproduced with permission.
Ducks: Ducks, photograph. © Robert J. Huffman/Field Mark Publications. Reproduced with permission.
Dugong: Dugong, lagoon, photograph. © Fred McConnaughey, Photo Researchers, Inc. Reproduced with permission
Dulbecco, Renato: Dulbecco, Renato, portrait. The Library of Congress.
Dune: Dermid, Jack. Sand dunes, moving dunes, photograph. © Jack Dermid, National Audubon Society Collection/Photo Researchers, Inc.Reproduced with permission.
Dust devils: Dust devil, photograph. JLM Visuals. Reproduced with permission.
Dust storm: Dust storm (during the Great Depression), photograph. The Library of Congress.
Dyes and pigments: Textiles, fibric dye, photograph. © Randy Duchaine/Stock Market. Reproduced with permission.
Dyslexia: Right hand writing dyslexically, photograph. © Will & Deni McIntyre/Science Source, National Audubon Society Collection/ Photo Researchers, Inc. Reproduced with permission.
Dysplasia: Micrograph of cervical smear, photograph. © Jonathan Ashton/Science Photo Library, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Eagles: Eagles, photograph. © Robert J. Huffman/Field Mark Publications. Reproduced with permission.
Ear: Ear, diagram of anatomy, photograph. Hans & Cassidy. Courtesy of Gale Research.
Earth: Space view of earth, photograph. U. S. National Aeronautics and Space Administration (NASA).
Earth: Earth rising over moon, photograph. U. S. National Aeronautics and Space Administration (NASA).
Earth Science: Geosphere project, view of North America, photograph. © Tom Van Sant/Stock Market. Reproduced with permission.
Earth's interior: Earth’s interior, illustration. Robert L. Wolke. Reproduced with permission.
Earth's interior: Earth's interior, diagram, photograph. Hans & Cassidy. Courtesy of Gale Research.
Earth's magnetic Field: Earth's magnetic field, photograph. © NASA /Phototake NYC Reproduced with permission.
Earthquake: Alaska, Earthquake, photograph. JLM Visuals. Reproduced with permission.
Earthquake: Earthquake in Chatsworth, January 17, 1994. Robert A. Eplett/OES/Governor’s Office of Emergency Services.
Earthquake: Satellite view of earthquake, photograph. © Massonnet ET AL, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Earthquake measurement scale: Earthquake measurement scale, photograph. (c) C. D. Miller/U. S. Geological Survey Photographic Library Denver, CO. Reproduced with permission. Eastern European Pollution: Eastern European Pollution. © K. Martensen, Greenpeace. Reproduced with permission.
Eccles, John C.: Eccles, John C., portrait. The Library of Congress.
Eclipse: Solar eclipse, photograph. © Francois Gohier/Science Source, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Ecojustice: Ecojustice, photograph. © Zachary Singer, Greenpeace. Reproduced with permission.
Ecological disturbance: Bare trees in open field, photograph. JLM Visuals. Reproduced with permission.
Ecological economics: Ecological economics. © Sam Kittner, Greenpeace. Reproduced with permission.
Ecological integrity: Ecological integrity, photograph. Lee Klinger, National Center for Atmospheric Research/University Corporation for Atmospheric Research/National Science Foundation 1225. Reproduced with permission.
Ecological Monitoring: Ecological monitoring, photograph. © R. L. Elderkin, Jr., U. S. Geological Survey.
Ecological pyramids: Ecological pyramids, line drawing. Hans & Cassidy. Courtesy of Gale Research.
Ecologists, Biologists: Ehrlich, Paul, (cigar in hand), photograph. The Library of Congress.
Ecology: Ecology, photograph. © Robert F. Bailey, U. S. Forest Service.
Ecosystem: Ecosystem, underwater, illustration. Hans & Cassidy. Courtesy of Gale Research.
Ecosystem: Ecosystem, illustration. Hans & Cassidy. Courtesy of Gale Research.
Ecotone: Boundy between Pikes Peak and Ramparts Range, photograph. © W. B. Hamilton. U. S. Geological Survey Photographic Library Denver, Colorado.
Edelman, Gerald: Edelman, Gerald, portrait. The Library of Congress.
Edema: Lymphoedema in arm, elderly woman, photograph. © Dr. P. Marazzi, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Edison, Thomas Alva: Edison, Thomas Alva, portrait. The Library of Congress.
Eel: Eel swimming, photograph. © James T. Spencer, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
El nino and la nina: El nino and la nina, photograph. National Center for Atmospheric Research/University Corporation for Atmospheric Research/National Science Foundation 756. Reproduced with permission.
Eland: Bull eland, photograph. © Suen-O Linoblad,National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Elapid snakes: Cobra, photograph. © Tom McHugh, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Electric Circuit: Electric circuit, man working on electric control panals, photograph. © Rick Altman/Stock Market. Reproduced with permission.
Electric Current: Electric current between two objects, photograph. © Phil Jude, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Electric motor: Direct current motor, photograph. © Bruce Iverson/Science Photo Library, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Electrical power supply: Interior image, electrical power plant, photograph. JLM Visuals. Reproduced with permission.
Electricity: Ceramic insulators, photograph. Robert Essel/Bikderberg/Stock Market. Reproduced with permissions.
Electrocardiogram: Electrocardiogram, Doctor with patient, photograph. © Mug Shots/Stock Market. Reproduced with permission.
Electrocardiogram (ECG): Electrocardiogram, diagrams, photograph. Hans & Cassidy. Courtesy of Gale Research.
Electrocardiogram (ECG): Electrocardiogram, electrode placement points, photograph. Hans & Cassidy. Courtesy of Gale Research.
Electrocardiogram (ECG): Electrocardiogram, graph, deflections and intervals, photograph. Hans & Cassidy. Courtesy of Gale Research.
Electrocardiogram (ECG): Electrocardiogram, rhythm charts, photograph. Hans & Cassidy. Courtesy of Gale Research.
Electrocephalogram (EEG): Woman undergoing EEG, photograph. © Catherine Pouedras/Science Photo Library, National Audubon Society Collection/Photo Researchers, Inc. Reproduced by permission.
Electrolysis: Electolysis, photograph. Robert L. Wolke. Reproduced by permission.
Electrolyte: Electolyte, photograph. Robert L. Wolke. Reproduced by permission.
Electromagnetic Field: Electromagnetic field, electrons, photograph. © John Howard, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Electromagnetic induction: Electromagnetic induction, illustration, photograph. Hans & Cassidy. Courtesy of Gale Research.
Electromagnetic induction: Electromagnetic induction, chats, photograph. Hans & Cassidy. Courtesy of Gale Research.
Electromagnetic induction: Electromagnetic induction, chart, illustration. Hans & Cassidy. Courtesy of Gale Research.
Electromagnetic induction: Electromagnetic induction, light bulb, photograph. Hans & Cassidy. Courtesy of Gale Research.
Electromagnetic spectrum: Electromagnetic spectrum, illustration. Robert L. Wolke. Reproduced with permission.
Electron: Electron, illustration. Hans & Cassidy. Courtesy of Gale Research.
Electron Microscope: Electron microscope, SEM screens, photograph. © Philippe Plailly/Eurelious/Science Photo Library, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Electronics: Computer chip board, photograph. © Peter Vadnai/Stock Market. Reproduced with permission.
Electrophoresis: Electrophoresis, DNS, photograph. Hans & Cassidy. Courtesy of Gale Research.
Electrophoresis: Electrophoresis, moving boundary electrophoresis, illustration. Hans & Cassidy. Courtesy of Gale Research.
Electrophoresis: Electrophoresis, SDS-Page Gel, photograph. Hans & Cassidy. Courtesy of Gale Research.
Electrostatic device: Van de Graff generator, photograph. © Adam Hart-Davis/Science Photo Library, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Element| transuranium: Element transuranium, illustration. Hans & Cassidy. Courtesy of Gale Research.
Element, transuranium: Element transuranium, illustration. Hans & Cassidy. Courtesy of Gale Research.
Elephant shrew: Elephant shrew, photograph. © Tom McHugh, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Elephant snout fish: Elephant lip-fish, photograph. © Jean-Michel, National Audubon Society Collection/ Photo Researchers, Inc. Reproduced with permission
Elephantiasis: Elephantiasis in leg, photograph. C. James Webb/Phototake NYC. Reproduced with permission.
Elephants: Elephant, Asian, photograph. © Ben Simon/Stock Market. Reproduced with permissions.
Elephants: Elephants, photograph. Michael Burgess/Bikderberg/Stock Market. Reproduced with permissions.
Elevator: Architecture, skyward interior of hotel, photograph. © Kacs Maciag/Stock Market. Reproduced with permission.
Elm: Elm, photograph. James Lee Sikkema. Reproduced by permission.
Embroyo and Embroyonic: Human fetus, five to six weeks, photograph. © Petit Fromat/Nestle, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Embryology: Embryology, turnips, photograph. © Dr. Jeremy Burgess, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Emission: Pollution, Nickel smelter, photograph. © J. Polleross/Stock Market. Reproduced with permission.
Endangered Species: Golden frog, photograph. JLM Visuals. Reproduced with permission.
Endemic: Endemic, photograph. © Chris Childs, Greenpeace. Reproduced with permission.
Endemic species: Endemic species, photograph. © Luther C. Goldman, National Park Service.
Enders, John F.: Enders, John F., portrait. The Library of Congress.
Endoscopy: Larynx endoscopy, photograph. © National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.
Endothermic: (c) U.S. Fish & Wildlife Service.
ENER 1957: Nuclear reactors, portrait. The Library of Congress.
Energy: Waterfall, photograph. JLM Visuals. Reproduced with permission.
Energy and the environment: Energy and the environment, photograph. U. S. Department of Energy, Washington DC.
Energy Paths: Energy paths, photograph. © James Perez, Greenpeace. Reproduced with permission.
Energy paths: Energy paths, photographs. U. S. Department of Energy, Washington DC.
Engineering: Computer aided work station, man, photograph. © David Parker/Science P