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DAL sixteen years of age, he went abroad as a writer in the East India company's service. His attention was soon after accidentally directed to the subject of commercial intercourse with the eastern archipelago, and so deeply did he become interested in this matter, that, in spite of Lord Pigot's earnest remonstrances, he resigned his situation, and undertook a voyage among the eastern islands. His efforts, however, to establish commercial relations with the inhabitants, though very promising for a time, ultimately ended in disappointment. He returned to England in 1765, and four years later he received from the company a grant of £5000, as a compensation for his having relinquished the office of secretary at Madras to proceed on his eastern voyage. On the appointment of Lord Pigot to be governor of Fort St. George in 1775, Dalrymple was sent out to Madras as a member of council, and as one of the committee of circuit. He was recalled, however, in 1777, but two years later he was appointed hydrographer to the East India company. In 1795 a similar office was established by the admiralty, and conferred upon Dalrymple, who held it until 1808, when they requested him to resign on the ground of superannuation, and on his refusal dismissed him from office. He died within a month, it is said, of vexation. He was the author of numerous works, some of them of permanent value. A list of his productions will be found in the European Magazine for December, 1802.—J. T.  , a British general, was the grandson of Hew, the third son of the first Viscount Stair, and was born in 1750. He entered the army at an early age; served on the continent under the duke of York in 1793, and was present at the attack upon the fortified camp of Famars, and at the siege of Valenciennes. In 1808 he was sent to take the command of the British army in Portugal, and arrived just after the battle of Vimiero. His extreme caution prevented the pursuit of the defeated French army, which Sir Arthur Wellesley in vain urged upon him; and the convention of Cintra, which followed, though it cleared Portugal of the enemy, excited great dissatisfaction in England. It was defended, however, by the government, and justified by the sentence of the court of inquiry. Sir Hew obtained the rank of general in 1812, was created a baronet in 1814, and died in 1830.—J. T.  DALRYMPLE,, a distinguished surgeon, born in 1804 at Norwich, where his father was a medical practitioner. The early part of his professional education was conducted by his father. He afterwards studied at the university of Edinburgh; and in 1827 he became a member of the Royal College of Surgeons of London, and settled in the metropolis. During the latter part of his career he devoted himself entirely to ocular surgery, having been in 1832 elected assistant-surgeon to the Royal Opthalmic hospital, and surgeon in 1843. In 1847 he retired from that office on account of ill health, and was appointed consulting surgeon. His work on the "Anatomy of the Eye," by which he is best known, was published in 1834. A splendid work on the pathology of that organ he just lived to complete. He was known, however, not only as a surgeon, but also as a naturalist and microscopic observer. He was an original member of the Microscopical Society of London, and was a frequent attendant at its meetings: in its Transactions we find a valuable paper by him "On the Arrangement of the Capillary Vessels of the allantoid and vitelline membranes in the incubated egg." In 1849 he read a paper before the Royal Society "On a hitherto undescribed animalcule allied to the genus Nolommata of Ehrenbergs." In 1850 he was elected a fellow of the Royal Society. In 1851 he was put on the council of the College of Surgeons. He was one of the founders of the Royal College of Chemistry, and zealously promoted its interests. He died at his residence in Grosvenor Street, London, on the 2nd of May, 1853.—E. L.  DALRYMPLE,, an eminent surgeon, was born at Norwich, of a Scottish family, in 1772, and died on the 5th of December, 1847. At the free school of his native town he was a favourite pupil of the celebrated Dr. Parr, who continued his attached friend as long as he lived. On leaving school he went to London, and pursued his surgical studies at the then united hospitals of St. Thomas and Guy's, under the elder Cline and Sir Astley Cooper. On his return to Norwich in 1793 he opened a surgery in his father's house; but his professional progress was retarded by his political and ecclesiastical opinions, which were somewhat too liberal to be popular. In 1814, however, he succeeded to the surgeoncy of the Norfolk and Norwich hospital, vacated by Dr. Rigby. He had already been appointed assistant, and in that capacity had attracted the attention of the profession by successfully performing the then very rare operation of placing a ligature upon the common carotid artery. He soon attained great eminence as a surgeon. He resigned his position in the hospital in consequence of failing health in 1839.—R. M., A.  * DALSGAARD,, a Danish painter, born in Jutland in 1824. He came to Copenhagen in his eighteenth year to study art under Norby. The first work of the pupil bore evidence of the master's teaching; but afterwards, being left to the guidance of his own genius, Dalsgaard struck into his own proper path, and his pictures now exhibit a powerful earnest mind, combined with great original genius.—M. H.  DALTON,, the author of the atomic theory of modern scientific chemistry, was born at Eaglesfield in Cumberland on September 5th, 1766. His father was a weaver of woollen, and his mother eked out the living of the family by selling a few articles in the village. They afterwards succeeded to a small family estate of about sixty acres. John was taught at a school of the Society of Friends, to which the family belonged. Perceiving the youth was of an active turn of mind, a gentleman of the neighbourhood assisted him in his lessons, and with such success, that at the age of twelve Dalton himself was appointed to conduct the school where he had been a scholar. At fourteen he went to Kendal as assistant in the school of his cousin, whom he and his brother Jonathan succeeded in 1785. Here he became an active student of nature, beginning with the phenomena most before his eyes—the hills and their mists—and diversifying this study with botany and mineralogy, in which sciences he made considerable progress. It was here that he became acquainted with Gough, a true student of nature also—blind almost from his birth—the tutor of Whewell and the admired of Wordsworth. Gough was at that time the representative of natural science at Kendal, and Dalton obtained the use of his stock of books and apparatus, read aloud for him, and benefited by his conversation and instruction. Dalton's first attempts at writing were sent to the Gentleman's Magazine; and his industry was stimulated by receiving prizes given for the best answers to the mathematical and other questions propounded in that periodical.

In 1793 he was appointed teacher of mathematics in the New college, Manchester; and he may be said, therefore, to have been the successor of Priestley, as, besides mathematics, he taught the physical sciences. Here we find him writing his first book, called "Meteorological Observations and Essays." In these essays he strongly insists that the vapour of water exists in the air as a fluid sui generis, that it is the same as steam, and that it is not in combination with the air, as had been so often supposed, but entirely independent; that this vapour of water is taken up equally by a space containing air, and a space containing no air, and that the pressure of the air does not, therefore, regulate the condensation of vapour. He discusses the cause of the rise and fall of the barometer, and decides that it is owing to the varying amount of vapour in the atmosphere, which is greater according to the temperature, warm air containing more than cold air.

In 1794 he became a member of the Literary and Philosophical Society of Manchester, then only a few years old, but already numbering among its members some eminent cultivators of science. He was destined to spend the greater portion of his life in the service of this society; for no sooner were his talents recognized than he was appointed secretary, with residence in the society's premises. He was afterwards promoted to the dignity of president, and indeed from 1800 till the end of his life was sole manager of the society's affairs. He read his first paper in 1794; it was entitled "Extraordinary facts relating to the vision of colours." He found that he could see only two or at most three colours, instead of six or seven, in the solar spectrum—these were yellow and blue, or yellow, blue, and purple. Crimson to his eye appeared a muddy blue, red sealing-wax looked like grass, a florid complexion seemed a dusky blue. Dr. George Wilson, who finds the defect not uncommon, calls it chromatopseudopsis, the false vision of colours, or colour blindness.

Dalton's next papers were upon springs, rain, and dew, and showed that water expanded by heat equally above and below the point of maximum density. When treating of the heat and cold obtained by the mechanical condensation and rarefaction of air, he showed that gases expand nearly one-tenth of their volume for every degree of heat, and thus arrived at a great and valuable law relative to their equable expansion. In 1801 he produced 