the atmospheric conditions daily indicated on a large map, and to utilize the generalizations made in weather forecasts, and the first to embrace a continent under a single system, British America and Mexico being included in the field of observation. In 1852, on the reorganization of the American lighthouse system, he was ap pointed a member of the new board ; and on the resignation of Admiral Shubrick as its chairman, Henry, in 1871, became the pre siding officer of the establishment a position he continued to hold during the rest of his life. His diligent investigations into the efficiency of various illuminants under differing circumstances, and into the best conditions for developing their several maximum powers of brilliancy, while greatly improving the usefulness of the line of beacons along the extensive coast of the United States, eifected at the same time a great economy of administration. His equally careful experiments on various acoustic instruments also re sulted in giving to his country the most serviceable system of fog- signals known to maritime powers. In the course of these varied and prolonged researches from 1865 to 1877, he also made im portant contributions to the science of acoustics ; and he established by several series of laborious observations, extending over many years and along a wide coast range, the correctness of Professor Stokes s hypothesis (Report Brit. Assoc., 1857, part ii. 27) that the wind exerts a very marked influence in refracting sound-beams. The complex conditions of such acoustic refraction he found to be exceedingly variable and curious (Report American Lighthouse Hoard, 1874, 1875, and 1877). From 1868 Henry continued to be annually chosen as president of the National Academy of Sciences ; and he was also president of the Philosophical Society of Washing ton from the date of its organization in 1871.
Henry was by general concession the foremost of American physicists. He was a man of varied culture, of large breadth and liberality of views, of generous impulses, of great gentleness and courtesy of manner, combined with equal firmness of purpose and energy of action. He died at Washington, May 13, 1878.
(s. f. b.)
HENRY, Matthew (1662–1714), the author of the well known and justly popular Exposition of the Old and New Testaments, was born at Broad Oak, a farm-house on the confines of Flintshire and Shropshire, on the 18th of October 1662. He was the son of Philip Henry, one of the 2000 ministers who were ejected from their livings in 1662 for refusing to conform to the Act of Uniformity. Unlike the majority of his fellow-sufferers, Philip Henry, who through his wife was the possessor of private means, was spared all personal privation or hardship as the con sequence of his nonconformity, and was thus enabled to give a good education to his son. Having received his preliminary education from his father and a tutor named Turner, Henry was next removed to an academy at Islington, whence he proceeded to become a student of law at Gray s Inn. His legal studies, however, had not advanced far when he relinquished them for theology, to which he thenceforth devoted himself. la 1687 he became minister of a Pres byterian congregation at Chester, whence in 1712 he was translated to Hackney. Two years later (June 22, 1714), he died suddenly of apoplexy at Nantwich while on a journey from Chester to London. Henry s Exposition, the work by which he is now chiefly remembered, is a commen tary of a practical and devotional rather than of a critical kind, ranging over the whole of the Old Testament and extending into the New as far as to the end of the Acts. At .this .point it was broken off by the author s death, but the work was finished by a number of clergymen, whose names are recorded in most editions of the book. In a critical point of view, it may be said to be quite valueless ; yet its. unfailing good sense, its discriminating thought, its high moral tone, its simple piety, and its altogether singular felicity of practical application, combine with the well-sus tained flow of its racy English style to secure for it, and deservedly, the foremost place among works of its class.
Besides the Exposition, Matthew Henry wrote a Life of Mr Philip ffcnry; The Communicant s Companion; Directions for Daily Communion with God; A Method for -Prayer; and A Scriptural Catechism, all of which, along with numerous -sermons, have been frequently ;reprinted, both separately and in complete editions of his Miscellaneous Works. His life has been written by W. Tong fcLondon, 1816), by Davis (prefixed to Exposition, ed. 1844), by Hamilton (Ghristiaii Biography, 1853), by C. Chapman (1859), and UyJi B. Williams (1828, new ed. 1865).-.-i-.>.- -