Robert Hooke (1635-1703)
No portrait survives of Robert Hooke. Hooke was perhaps the single 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. Among many other accomplishments, he formulated an equation describing elasticity that is still used today ("Hooke's Law"); assisted in studying the physics of gases; invented or improved meteorological instruments such as the barometer 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.
Relatively little is known about Robert Hooke's life. He was born on July 18, 1635, at Freshwater, on the Isle of Wight, the son of a churchman. He was apparently largely educated at home by his father. He was able to enter Westminster School at the age of thirteen, and from there went to Oxford, where some of the best scientists in England were working at the time. Hooke impressed them with his skills at designing experiments and building equipment, and soon became an assistant to the chemist Robert Boyle. In 1662 Hooke was named Curator of Experiments of the newly formed Royal Society of London -- meaning that he was responsible for demonstrating new experiments at the Society's weekly meetings. He later became Gresham Professor of Geometry at Gresham College, London, where he lived for the rest of his life. He died in London on March 3, 1703.
Hooke's reputation in the history of biology largely rests on his book Micrographia, published in 1665. Hooke devised a compound microscope and illumination system, one of the best such microscopes of his time, and used it in his demonstrations at the Royal Society's meetings. With it he observed organisms as diverse as insects, sponges, bird feathers and many more. Micrographia was an accurate and detailed record of his observations, illustrated with magnificent drawings. It was a best-seller of its day.
Perhaps his most famous microscopical observation was his study of thin slices of cork. In "Observation XVIII" of the Micrographia, he wrote:
“. . . I could exceedingly plainly perceive it to be all perforated and porous, much like a Honey-comb, but that the pores of it were not regular. . . . 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. In fact, it was Hooke who coined the term "cells": the boxlike cells of cork reminded him of the cells of a monastery. Hooke also reported seeing similar structures in wood and in other plants. In 1678, after Anthony van Leeuwenhoek had written to the Royal Society with a report of discovering "little animals" -- bacteria and protozoa -- Hooke was asked by the Society to confirm Leeuwenhoek's findings. He successfully did so, thus paving the way for the wide acceptance of Leeuwenhoek's discoveries. Hooke noted that Leeuwenhoek's simple microscopes gave clearer images than his compound microscope, but found simple microscopes difficult to use: he complained that they "much strained and weakened the sight."
Hooke was also a keen observer of fossils and geology. While some fossils closely resemble living animals or plants, others do not -- because they are extinct, or because they represent living species which are undiscovered or poorly known. In the seventeenth century, a number of hypotheses had been proposed for the origin of fossils. One widely accepted theory, going back to Aristotle, stated that fossils were formed from stone and grew within the Earth. They looked like living beings but were not.
Hooke examined fossils with a microscope -- the first person to do so -- and noted cllose similarities between the structures of petrified wood and fossil shells on the one hand, and living wood and living mollusc shells on the other. In Micrographia he compared a piece of petrified wood with a piece of rotten oak wood, and concluded that dead wood could be turned to stone by the action of water rich in dissolved minerals, which would deposit minerals throughout the wood.
Hooke's Discourse of Earthquakes, published two years after his death, shows that his geological reasoning had gone even further. “It seems not improbable, that the tops of the highest ... Mountains in the World have been under Water, and that they themselves most probably seem to have been the Effects of some very great Earthquake." Hooke continued to study fossils and compare them with living organisms. He concluded that many fossils represented organisms that no longer existed on Earth: "There have been many other Species of Creatures in former Ages, of which we can find none at present; and that 'tis not unlikely ... 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 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 Charles 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.
no bounds – keine Grenzen, naval technology – Nautik, accomplishments – Leistungen, equation – Gleichung, improve – verbessern, contribute – beitragen, contribution – Beitrag, findings – Entdeckungen, apparently – offensichtlich, anscheinend, scientists – Naturwissenschaftler, impresse – beeindrucken, equipment – Ausrüstung, Gerätschaften, rest on – beruhen auf, devise – etwas erdenken, compound microscope – zusammengesetztes Mikroskop, illumination system – Beleuchtungssystem, observe – beobachten, observer – Beobachter, diverse – vielfältig, diversity – Vielfalt, sponges – Schwämme, record – Aufzeichnung, drawing – Zeichnung, cork – Kork, perceive – wahrnehmen, perception – Wahrnehmung, Honey-comb – Bienenwabe, cells – Zellen, cell walls – Zellwände, tissue – Gewebe, monastery – Kloster, protozoa – Protozoen, Einzeller, confirm – bestätigen, confirmation – Bestätigung, paving the way – den Weg ebnen, simple microscopes – Mikroskop mit nur 1 Linse, complain – sich beklagen, strain – anstrengen, belasten, strapazieren, Druck, Belastung, weaken – schwächen, keen – begeistert, leidenschaftlich, scharf, resemble – ähneln, extinct – ausgestorben, species – Arten, propose – vorschlagen, origin – Ursprung, examine – untersuchen, petrified – versteinert, shells – Muschelschalen, Schneckenhäuser, mollusc – Mollusken (Weichtiere: Schnecken, Muscheln, Tintenfische), rotten – faulig, conclude – schlussfolgern, conclusion – Schlussfolgerung, dissolved minerals – gelöste Mineralien, deposit – ablagern, deposition – Ablagerung, Discourse of Earthquakes – Abhandlung/ Vortrag über Erdbeben, reasoning – Gedankengang, logisches Denken, improbable/ unlikely – unwahrscheinlich, 'tis – it is, grasp – begreifen, cardinal principle – Grundprinzip, remains – Überreste, realize – erkennen