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                          Robert Hooke (1635-1703)

                                  

No portrait survives of Robert Hooke, and his name is somewhat obscure
today, due in part to the enmity of his famous, influential, and extremely
vindictive colleague, Sir Isaac Newton. Yet Hooke was perhaps the greatest
experimental scientist of the seventeenth century. His interests knew no
bounds, ranging from physics and astronomy, to chemistry, biology, and
geology, to architecture and naval technology; he collaborated or
corresponded with scientists as diverse as Christian Huygens, Antony van
Leeuwenhoek, Christopher Wren, Robert Boyle, and Isaac Newton. Among other
accomplishments, he invented the universal joint, the iris diaphragm, and an
early prototype of the respirator; invented the anchor escapement and the
balance spring, which made more accurate clocks possible; served as Chief
Surveyor and helped rebuild London after the Great Fire of 1666; worked out
the correct theory of combustion; assisted Robert Boyle in working out the
physics of gases; worked out the physics of elastic materials; invented or
improved meteorological instruments such as the barometer, anemometer, and
hygrometer; and so on. He was the type of scientist that was then called a
virtuoso -- able to contribute findings of major importance in any field of
science. It is not surprising that he made important contributions to
biology and to paleontology.

Hooke's reputation as a biologist largely rests on his book Micrographia,
published in 1665. Hooke devised the compound microscope and illumination
system shown above, one of the best such microscopes of his time. With it he
observed objects as diverse as insects, sponges, bryozoans, and bird
feathers, making magnificent drawings and accurate and detailed
observations.

        Perhaps his most famous microscopical observation was his study of
        thin slices of cork. He wrote:

     . . . I could exceedingly plainly perceive it to be all perforated and
     porous. . . these pores, or cells, . . . were indeed the first
     microscopical pores I ever saw, and perhaps, that were ever seen, for I
     had not met with any Writer or Person, that had made any mention of
     them before this.

Hooke had discovered plant cells -- more precisely, what Hooke saw were the
cell walls in cork tissue (as shown in the illustration to the left).

Hooke was also a keen observer of fossils and geology. In the seventeenth
century, a number of hypotheses had been proposed for the origin of fossils;
one widely accepted theory stated that fossils were formed within the Earth
by some sort of "extraordinary Plastick virtue," or force giving rise to
stones that looked like living beings but were not. Hooke examined fossils
with a microscope -- the first person to do so -- and noted close
similarities between the structures of petrified wood and fossil shells on
the one hand, and living wood and living mollusc shells on the other. He
concluded that the shell-like fossils that he examined really were "the
Shells of certain Shel-fishes, which, either by some Deluge, Inundation,
earthquake, or some such other means, came to be thrown to that place."
Hooke observed that many fossils represented extinct organisms, writing
"There have been many other Species of Creatures in former Ages, of which we
can find none at present. . . 'tis not unlikely also but that there may be
divers new kinds now, which have not been from the beginning."

Hooke had grasped the cardinal principle of paleontology -- that fossils are
not "sports of Nature," but remains of once-living organisms that can be
used to help us understand the history of life. Hooke realized, two and a
half centuries before Darwin, that the fossil record documents changes among
the organisms on the planet, and that species have both appeared and gone
extinct throughout the history of life on Earth. These questions of the
nature of fossils and the possibility of extinction would continue to
challenge natural scientists, from Edmund Lhwyd and John Ray down to
Jean-Baptiste Lamarck and Georges Cuvier.

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A brief biography of Hooke, with a listing of his contributions to
mathematics, is part of the resources in the history of mathematics
maintained at the School of Mathematics of Trinity College, Dublin. Somewhat
more extensive information on Hooke's life and accomplishments is available
in this biography, part of the History of Mathematics archive. There is also
information about Hooke's contributions to microscopy in the excellent,
thorough History of the Light Microscope pages.
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