Robert Hooke

English physicist Robert Hooke discovered the law of elasticity, known as Hooke’s law. He also conducted research in a remarkable variety of fields. In 1655 Hooke was employed by Robert Boyle to construct the Boylean air pump. Five years later, Hooke discovered his law of elasticity, which states that the stretching of a solid body is proportional to the force applied to it. The law laid the basis for studies of stress and strain and for understanding of elastic materials. He applied these studies in his designs for the balance springs of watches. In 1662 he was appointed curator of experiments to the Royal Society of London and was elected a fellow the following year. One of the first men to build a Gregorian reflecting telescope, Hooke in 1664, discovered the fifth star in the Trapezium, an asterism in the constellation Orion, and first suggested that Jupiter rotates on its axis. Hooke, along with Leeuwenhoek, was the first to construct a practical microscope and use it to study nature. In 1665 Hooke published his famous book Micrographia, a historically significant book about his observations through various microscopes. It is particularly notable for being the first book to illustrate insects, plants etc. as seen through microscopes. It was also the first major publication of the Royal Society and it became the first scientific best-seller, inspiring a wide public interest in the new science of microscopy. In this book he also included his studies and illustrations of the crystal structure of snowflakes,and discussed the possibility of manufacturing artificial fibres by a process similar to the spinning of the silkworm. Hooke was the first to use the biological term, cell. Hooke also invented some of the methods and devices used to make clocks extremely accurate for the time, maritime navigational instruments and other optical and mechanical devices. In 1672 he discovered the phenomenon of diffraction (the bending of light rays around corners). Hooke suggested that the force of gravity could be measured by utilizing the motion of a pendulum (1666) and attempted to show that the Earth and Moon follow an elliptical path around the Sun. He stated the idea of inverse square law to describe planetary motions in 1678, a law that Newton later established in a sound form. Hooke complained that he was not given sufficient credit for the law and became involved in bitter controversy with Newton.