missioners were called, to whom the government of the country

was intrusted in 1596; and he was subsequently employed in various missions to Denmark, and to the neighbouring states. He was one of the defenders of Queen Mary, and prepared a short narrative of her life and death for the purpose of vindicating that princess against the aspersions of David Chytræus. He accompanied his royal master to England, where he was knighted in 1605, and received a pension of £300 per annum. In 1620 he retired to an estate which he possessed at Easter Seaton near Arbroath, where he died in 1628. His uncle Henry Scrimgeour bequeathed to him his library, which was one of the most valuable in Europe, and contained some MSS. of great interest. But Sir Peter was more intent upon aggrandizing his family than promoting the progress of learning; and his uncle's disquisitions, which Buchanan says were well worth printing, were never published, and are now lost. Sir Peter was twice married, and left a very numerous family.—J. T. YOUNG, Thomas, M.D., the most clear-thinking and far-seeing mechanical philosopher of the nineteenth century, and one of its most accomplished and profound scholars, was born at Milverton in Somersetshire, on the 13th of June, 1773, and died in London on the 10th of May, 1829. His childhood and early youth were marked chiefly by the extraordinary assiduity, extent, and method of his studies, especially in ancient literature and in mathematics. They were carried on partly at Compton school, but chiefly at home. He acquired at a very early age a great mastery of the Greek language. It is to be remarked, in connection with his later achievements in physical science, that when little more than a boy in years, he had carefully read and digested the whole of the Principia of Newton; a task very seldom thoroughly performed, but essential to the training of a discoverer in mathematical physics. From 1787 till 1792 he acted as tutor to Mr. Hudson Gurney of Youngsbury in Hertfordshire. In 1792 he commenced his education for the medical profession at St. Bartholomew's hospital in London. In 1793 he sent to the Royal Society a paper on the muscular fibres of the eye, which led to his election as a fellow of that body in 1794. In 1791-95 he prosecuted his medical studies at the university of Edinburgh under Gregory, Black, and Monro; where also he employed his knowledge of Greek to assist Professor Dalzel in the editing of his Αναλέκτα Ἑλληνκὰ. Here also for the first time in his life he varied his graver occupations by the study of such accomplishments as music, dancing, riding, and fencing. In 1796 he continued the study of medicine at Gottingen, where he took the degree of M.D. In 1797, in order to complete his medical studies, he entered the university of Cambridge as a fellow-commoner of Emanuel college. In the same year a kind and excellent uncle. Dr. Brocklesby, who had aided and encouraged him in his studies, died, and bequeathed to him a moderate fortune, which, without relieving him from the necessity of working at his profession, was sufficient to give him some freedom to follow the bent of his genius in the advancement of science. In 1800 he began to practise medicine in London. In 1801, 1802, and 1803 he communicated to the Royal Society, in a series of papers on the theory of light and colours, some of the most important discoveries ever made in physical science—embracing the fact of the interference of light, then first made known; the experimental investigation of the laws of that fact, and of its relations to the phenomena of diffraction, and of the colours of thin plates, thick plates, fibres, striated surfaces, &c.; and the theory by which that fact and its laws are accounted for, according to the hypothesis of luminiferous waves (which had been first put into shape by Huyghens). From 1801 till 1804 he held the professorship of natural philosophy in the Royal Institution, and delivered a series of lectures which he published in 1807, and which to this day forms the best existing compendium of the elementary principles of physics. Considering that this work is composed of popular lectures, from which the symbols and technical language of mathematics were designedly excluded, its precision, accuracy, and completeness, are marvellous, and are combined with almost unparalleled brevity and clearness. It was far in advance of the time when it appeared; and, indeed, the popular treatises of the present day still lag behind it, after a lapse of sixty years. The original edition, in 2 vols. 4to, is highly prized on account of the beauty and accuracy of the illustrations of the phenomena of light which it contains; but a new edition, in 2 vols. 8vo, has the advantage of containing accounts of the recent progress of science, added by Professor Kelland. In 1804 he laid before the Royal Society his remarkable paper on the cohesion of fluids, containing the soundest, and at the same time the amplest, theory of capillary attraction which had then appeared. On the 14th of June, 1804, he contracted what proved a most happy marriage with Miss Eliza Maxwell, a lady belonging to a branch of the Scottish family of Maxwell of Calderwood. Soon after resigning his professorship, Young ceased for many years to cultivate science openly, lest his being known to do so should raise a prejudice in the public mind against his skill as a physician; but he continued to pursue his scientific investigations in secret, and to publish their results anonymously. The only exceptions to this rule were his researches on scientific subjects directly connected with anatomy, physiology, and medicine, such as his hydraulic investigations on the motion of the blood, forming the Croonian lecture for 1808. In the same year he obtained the degree of M.D. of the university of Cambridge. During the sessions of 1809-10 and 1810-11, he delivered a series of lectures at the Middlesex hospital, afterwards embodied in a work called "An Introduction to Medical Literature, and System of Practical Nosology and Pharmacology," which was published in 1813. In 1811 he was appointed one of the physicians of St. George's hospital, and held the appointment till his death. Although he never became a popular or a fashionable physician, he appears to have had a fair amount of practice; and the reports of those who knew the results of his practice (especially in the cases which came under his care at the hospital), are highly favourable to the skill and success of his treatment. In 1815 he published his "Essay on Consumptive Diseases." He was a frequent contributor of scientific and literary articles to the Quarterly Review. Amongst the most valuable of his writings were his articles in the Encyclopædia Britannica, sixty-three in number; forty-six of which were biographic, and seventeen scientific. The latter contain accounts of some of his most important discoveries, and amongst them may be specified—"Bridge," "Cohesion," "Chromatics," "Egypt," and "Tides." In 1814 he began to turn his attention to the language and characters of ancient Egypt, in the interpretation of which he made greater and more important progress than had ever been accomplished by any previous, or, with the exception of Champollion, by any subsequent investigator. His earliest researches on this subject were published in 1816 in the Museum Criticum; they were embodied, along with further investigations, in the article "Egypt," already mentioned. About the same period Young began to throw aside the secrecy which had long covered his scientific pursuits. His attention was recalled to the theory of light by the discoveries of Fresnel, who, without knowing anything of Young's researches in 1800-1-2, rediscovered the law of interference, and applied it to the phenomena of diffraction with greater success than Young had done. Those two philosophers were made acquainted with each other's discoveries through the mediation of Arago, and a friendly correspondence ensued between them, in which there is not the slightest trace of jealousy, or even of rivalry. It appears that the great idea of transverse vibrations, the foundation of the theory of polarization, occurred to them independently about the same time; but it was first published by Young in a letter to Arago in 1817, and was by Arago communicated to Fresnel. The discoveries of each of them appear to have been best appreciated in the country of the other; for in 1825 the Royal Society of London awarded Fresnel the Rumford medal; and in 1827 the French Institute elected Young one of their eight foreign associates. In 1817 Young founded the Egyptian Society. He was frequently employed by the British government to report on scientific questions, and in 1818 was appointed secretary to the board of longitude. The immediate cause of his death, in his fifty-sixth year, was ossification of the aorta; but it was considered that his end was hastened by premature old age, brought on by excessive mental labour. Some of the merits of his works have already been mentioned; but it may be added that they are remarkable above all for their highly philosophical spirit, and in particular by the constancy with which they keep in view the distinction between beings and actions; a distinction too often lost sight of in crude theories of physics. His life was written, and his minor works collected and edited, by the late eminent mathematician. Dr. Peacock, dean of Ely.—W. J. M. R. YOUNG, Sir William, the historian of Athens, was born in Kent in 1750. His father was lieutenant-governor of Dominica,