KATER, HENRY, a mechanist of considerable eminence, was b. at Bristol in 1777, and d. in London in 1830. At his father's desire, he began the study of the law, but in 1794 relinquished his legal studies, and obtained a commission in the 12th regiment of foot, then stationed in India. During the following year he was actively engaged, under col. Lambton, in the trigonometric survey of India; and on his return iu 1808, became a student in the senior department at Sandhurst, and was shortly afterwards pro. moted to a company in the 62d regiment.
His contributions to science are chiefly to be found in the _Philosophical Transactions, to which, between the years 1813 and 1828, he contributed fifteen papers. The most important of these memoirs are those relating to his determination of the length of the seconds' pendulum at the latitude of London; and those which describe his "floating 'collimator," an instrument for aiding the determination of the horizontal or zenith points.
For the invention of this instrument, he received the gold medal of the royal astronom ical society. In addition to these memoirs, he was, conjointly with Dr. Lardner, the author of "A Treatise on Mechanics" in the Cabinet Cyclopedia. Most of the learned societies in Great Britain and on the continent enrolled him among their members. His memoirs on the verification and comparison of the standards of weights and measures of Great Britain and Ireland, induced the emperor of Russia to employ him to construct standards for the weights and measures of that country; and for these labors he received the order of St. Anne, and a diamond snuff-box. He died from an affection of the lungs in the 53d year of his age.