Page:A biographical dictionary of eminent Scotsmen, vol 9.djvu/52

it produced. James Horsburgh saw the necessity for more correct charts of the Indian Ocean than had yet been constructed, and he resolved to devote himself to the task, by making and recording nautical observations. The resolution, from that day, was put in practice, and he began to accumulate a store of nautical knowledge that served as the materials of his future productions in hydrography. In the meantime Horsburgh, a shipwrecked sailor, made his way to Bombay, and, like other sailors thus circumstanced, looked out for another vessel. This he soon found in the Gunjava, a large ship employed in the trade to China; and for several years after he sailed in the capacity of first mate, in this and other vessels, between Bombay, Calcutta, and China. And during this time he never lost sight of the resolution he had formed in consequence of his mishap at Diego Garcia. His notes and observations had increased to a mass of practical know- ledge, that only required arrangement; he had perfected himself, by careful study, in the whole theory of navigation ; and during the short intervals of his stay in different ports, had taught himself the mechanical part of his future occupation, by drawing and etching. It was time that these qualifications should be brought into act and use by due encouragement, and this also was not wanting. During two voyages which he made to China by the eastern route, he had constructed three charts, one of the Strait of Macassar, another of the west side of the Philippine Islands, and a third of the tract fromDampier Strait through Pitt's Passage, towards Batavia, each of these accompanied with prac- tical sailing directions. He presented them to his friend and former shipmate, Mr. Thomas Bruce, at that time at Canton ; and the latter, who was well fitted to appreciate the merits of these charts, showed them to several captains of India ships, and to Mr. Drummond, afterwards Lord Strathallan, then at the head of the English factory at Canton. They were afterwards sent home to Mr. Dalrymple, hydrographer to the East India Company, and published by the Court of Directors, for the benefit of their eastern navigation, who also transmitted a letter of thanks to the author, accompanied with the present of a sum of money for the purchase of nautical instruments. In 1796 he returned to England in the Carron, of which he was first mate ; and the excellent trim in which he kept that vessel excited the admiration of the naval connoisseurs of our country, while his scientific acquirements introduced him to Sir Joseph Banks, Dr. Maskelyne, the royal astronomer, and other men distinguished in science. After a trip to the West Indies, in which the Carron was employed to convey troops to Porto Rico and Trinidad, he obtained, in 1798, the command of the Anna, a vessel in which he had formerly served as mate, and made in her several voyages to China, Bengal, and England. All this time he continued his nautical observations, not only with daily, but hourly solicitude. His care in this respect was rewarded by an important discovery. From the beginning of April, 1802, to the middle of February, 1804, he had kept a register every four hours of the rise and fall of the mercury in two marine barometers, and found that while it regularly ebbed and flowed twice during the twenty-four hours in the open sea, from latitude 26 N. to 263 S., it was diminished, and sometimes wholly obstructed, in rivers, harbours, and straits, owing to the neighbourhood of the land. This fact, with the register by which it was illustrated, he transmitted to the Royal Society, by whom it was published in the Philosophical Transactions for 1805. Having also purchased, at Bombay, the astronomical clock used by the French ships that had been sent in quest of the unfortunate La Perouse, he used it in ascertaining the rates of his own chronometers, and in mak-