Charles Augustin Coulomb (1736-1806) rendered great service to electrical experimentation. He resurveyed the experiments of Cavendish, Priestley, and other pioneer electricians, and established a theory of molecular magnetization which provided a working formula to explain electrical currents and magnetic fields.
Simeon Denis Poisson (1781-1840) discovered the law of induced magnetism which bears his name.
Luigi Galvani (1737-1798) observed that the limbs of a frog are convulsed whenever they are connected up through the nerves and muscles with a metallic arc formed from more than one metal. He thought the convulsions were due to a peculiar fluid which he called galvanism, or animal electricity.
Another Italian, Alessandro Volta (1745-1827) discovered and explained the theory of the voltaic pile.
Nicholson and Carlisle discovered frictional electricity while William Cruickshank showed that a voltaic current decomposes solutions of metallic salts. William Hyde Wollaston used Cruickshank's discovery to prove that frictional and voltaic electric currents are identical. Humphry Davy (1778-1829) in 1807 established a new voltaic theory which combined the chemical and contact theories previously held, and showed that electrical and chemical attractions are produced by similar causes. Chemical affinity he found to be an essentially electrical phenomenon.
Francis Hawksbee, in 1705, communicated to the Royal Society a monograph which showed that when common air is passed over mercury in a well-exhausted receiver an electric light is produced. This was the first demonstration of the availability of electricity for the production of light.
Dufay (1699-1739) described positive and negative electric currents.
Watson determined, for the Royal Society, the velocity of an electric current and found it practically instantaneous.
These, and numerous lesser, discoveries did for electricity what the chemical discoveries of Priestley, Cavendish, Scheele, Boyle, Lavoisier, and others had done for chemistry.
The numerous voyages of discovery in the eighteenth century helped to develop the geographical sciences. Special expeditions were fitted out for the acquirement of geographical knowledge without any thought of trading profits. The Jesuits carried out a valuable survey of China and Mongolia early in the century. A Danish scientific expedition studied Arabia, the results of which were published by Niebuhr in 1772. James Bruce visited Abyssinia with the view of solving the ancient problem of the source of the Nile. Mungo Park studied the course of the Niger. Captain James Cook led a scientific expedition to Tahiti with the object of making astronomical observations. This resulted in one of the greatest and most valuable voyages of discovery in history. Cook determined the westernmost point of America in 1778 and his accounts of Bering Sea and Alaska revived interest in the Polar seas, which resulted in numerous Arctic and Antarctic expeditions yielding rich scientific returns.