day-labourer, and who taught himself the elements of mechanics and astronomy while employed as a farmer's boy in tending sheep. Ferguson published his first performance, his Dissertation on the Phenomena of the Harvest Moon, in 1747; his Astronomy in 1756; his Lectures on Mechanics, Hydrostatics, Pneumatics, and Optics, in 1760; and two or three other works between that date and his death in 1776. "Ferguson," it has been observed, "has contributed more than perhaps any other man in this country to the extension of physical science among all classes of society, but especially among that largest class whose circumstances preclude them from a regular course of scientific instruction. Perspicuity in the selection and arrangement of his facts, and in the display of the truths deduced from them, was his characteristic both as a lecturer and a writer." *

Another department of natural philosophy in which some splendid results were obtained by English experimenters of this era was that of electricity. Francis Hawksbee, who was admitted a fellow of the Royal Society in 1705, published several papers in the Transactions between that year and 1711, giving an account of a series of experiments, partly performed with a glass globe, in the course of which he noticed a number of facts connected with electrical attraction and repulsion, and in particular detected for the first time the remarkable phenomenon of the production of light by friction. A few years later the subject was taken up by Stephen Gray, a pensioner of the Charter House, who, with the aid of a very poor apparatus, made out a catalogue, which he published in 1720, of bodies which show electricity on being rubbed, and in 1732 discovered the conducting property inherent in bodies that are not electrical. The two opposite kinds, or exhibitions, of electricity (which he called the vitreous and the resinous) were discovered by Dufay, keeper of the King's Garden at Paris, before 1739; and he also showed that bodies similarly electrified repel, and those dissimilarly electrified attract, each other. The mode of accumulating the electric power by what is called the Leyden phial, or jar, was discovered by Cuneus and Lallemand in 1745. This experiment immediately attracted universal attention: Nollet in France, and Watson in England, in particular, applied themselves to find out the explanation of it; and the latter is asserted to have first conceived the hypothesis

*Penny Cyclopædia, x. 234.

of the redundancy of the electricity on the one side of the jar and its deficiency on the other. The same view occurred to the celebrated Benjamin Franklin, in America, who expounded it in a series of letters written to his friend Collinson, in London, in the course of the year 1747, in which he described the overcharged side of the jar as in a state of positive, and the undercharged of negative, electricity, and showed how all the known phenomena of electric action were to be accounted for on this hypothesis of only one kind of electric matter, or power, in opposite states. Franklin seems to have known little or nothing of what had been done by his predecessors either in France or England; of the theories, at least, either of Dufay or Watson, he appears never to have heard. Although not the first in the field, his penetrating and inventive genius immediately raised him to the first place among the cultivators of the new science. He soon improved the Leyden jar into the much more powerful apparatus of the electrical battery. Some of his earliest experiments had taught him the superior efficiency of sharp points both in attracting and giving out the electric matter; from the year 1749 he had inferred, from a great number of facts which he had observed and collected, the probable identity of electricity and lightning; and at last, in June, 1752, he established that truth by the decisive experiment of actually drawing down the electric matter from the clouds. This was followed by his invention of lightning-conductors, of which, however, none were erected in England till the year 1762.

The thermometer was invented at Florence soon after the middle of the seventeenth century, and by the assistance of that instrument, as manufactured by Fahrenheit and Réaumur, a considerable number of facts relating to the laws of heat had been gradually collected before the middle of the eighteenth. "The most judicious writer," says Professor Leslie, "that had yet appeared on the subject of heat, was Dr. Martine, of St. Andrew's, who studied medicine on the Continent, and, like the accomplished physicians of that period, cultivated learning and general science. His acute Essays, published in the years 1739 and 1740, not only corrected the different thermometric scales, but enriched philosophy by several well-devised and original experiments. Unfortunately the career of this promising genius was very short. Having in the pursuit of his profession accompanied Admiral Vernon in the fatal expedition against Carthagena, he

perished by a malignant fever." Mr. Leslie adds, that if Martine's investigations had been steadily prosecuted, they must have led to interesting results. About the year 1750, also, Dr. Cullen had his attention accidentally drawn to some facts connected with the curious subject of the production of cold by evaporation; but he did not pursue the inquiry.

In general chemistry the experiments begun by Boyle and Hooke had been followed up by their contemporary Dr. John Mayow, a physician of Oxford, whose tracts, written in Latin, on nitre and other connected subjects, were published in 1674. They announced many new and important facts illustrative of the phenomena of respiration and combustion. About the beginning of the next century the first general theory of combustion was given to the world by the German chemist Stahlthat which, under the name of the Stahlian or Phlogistic theory (from his imaginary phlogiston, or principle of inflammability), continued to be generally received down to the era of Black, Cavendish, and Priestley. Some considerable additions were made to our knowledge of aëriform bodies by Dr. Stephen Hales about a quarter of a century after this. But the most important chemical discoveries of this age are those of the celebrated Dr. Joseph Black, the pupil of Cullen. One was that of the new air discovered by him in the commencement of his career, and announced in his Experiments on Magnesia, Quicklime, and other Alkaline Substances, published in 1755. Fixed air, or,

as it is now called, carbonic acid, had indeed been long before recognized as something distinct from common air by Van Helmont; but his notice of it appears to have been quite forgotten when it was again detected by Black, who also first examined it with any degree of care, and ascertained its most remarkable properties. Another was the great discovery of latent heat, which he made a few years later. The most eminent names in the mathematical and physical sciences belonging to the earlier part of the reign of George III. are those of Cavendish (the discoverer of the composition of water), Priestley, Herschel (the discoverer of the planet Uranus), Bliss, who was the fourth, and Maskelyne, who was the fifth astronomer royal, Horsley, Vince, Maseres, Charles Hutton, James Hutton (the author of the Huttonian Theory of the Earth), Cullen, Brown (the propounder of the Brunonian System of Medicine), John and * Dissertation Fourth, in Encyc. Brit., p. 642.

William Hunter, the anatomists, &c. Under this head may also be noticed the several government voyages of discovery conducted by Commodore Byron, 1764-1766 (in the course of which he discovered the Duke of York's Island and the Isles of Danger); by Captain Wallis, 1766-1768 (in which he discovered the Island of Otaheite); by Captain Carteret, 1766-1769; by Captain Cook, accompanied by Mr. Green, the astronomer, and Dr. Solander and Mr. (afterwards Sir Joseph) Banks, the naturalists, 16681771 (in which the transit of Venus over the sun was observed at Otaheite 4th June, 1769, and New South Wales was discovered, and New Zealand re-discovered); by Captain Cook, 1772-1775 (in which he discovered New Caledonia); and by Captain Cook, 1776-1780 (in which the great navigator discovered the Sandwich Islands, and lost his life there, at Owhyhee, on the 14th of February, 1779).

351

THE LATTER PART OF THE EIGHTEENTH CENTURY.

THE death of Samuel Johnson, in the end of the year 1784, makes a pause, or point of distinction, in our literature, hardly less notable than the acknowledgment of the independence of America, the year before, makes in our political history. It was not only the end of a reign, but the end of kingship altogether, in our literary system. For King Samuel has had no successor; nobody since his day, and that of his contemporary Voltaire, who died in 1778, at the age of eighty-five, has sat on a throne of literature either in England or in France.

Of the literary figures, however, that had previously appeared upon the scene, many continued to be conspicuous for years after this date, some throughout the rest of the century or longer. Burke, the most eminent of them all, survived till 1797; and, having already raised himself to distinction by his publications and speeches in connexion with the American war, won his highest fame in the finishing part of his career by his wonderful oratorical displays on the impeachment of Hastings, and his writings, outblazing everything he had before produced, on the French revolution. Adam Smith did not die till 1790; his countryman, Dr. Robertson, not till 1793; Robertson's illustrious brother historian, Gibbon, not till 1794. Of the poets and cultivators of light literature, or the belles lettres, who have been already mentioned, Thomas Warton lived till 1790, Ossian Macpherson till 1796, Mason and his friend Horace Walpole till 1797, Joseph Warton till 1800. Other writers, again, who have been noticed in preceding pages, outlived Johnson by many years. Thus Beattie only died in 1803; Anstey, the author of the New Bath Guide, in 1805; John Home, the author of Douglas, in 1808; Bishop Percy and Richard Cumberland in 1811;