DABOLL, Nathan, educator, born about 1750; died in Groton, Connecticut, 9 March 1818. He was famous as a teacher, and instructed as many as 1,500 persons in navigation. He published a treatise on arithmetic, entitled the "Schoolmaster's Assistant" (New London, 1799), which was for a long time a standard Textbook; also the "Practical Navigator." In 1773 he began the annual publication of the " Connecticut Almanac."--His son, Nathan, born in Groton, Connecticut, in 1782; died there in 1863, was a member of the Connecticut House of Representatives in 1832-'3, of the senate in 1835-'6, and judge of probate in 1843-'5. He was joint author. In a work like this there is always difficulty in deciding where to place many of the names that begin with De. The general rule is that if the name retains its original form, it should be placed under the initial letter of the main word ; but the particle has coalesced with the main word, it should be found under D. If the reader misses any well-known name here, he should look for it under another letter. Daboll's "New Arithmetic," and compiled the "New England Almanac " from his father's death in 1818 until his own death.--David Austin, son of the second Nathan, born in Groton, Connecticut, in 1813, sat continuously in the state house of representatives from 1846 till 1871, and then served a term in the senate. He assisted his father in the preparation of the "New Arithmetic," and since his father's death has continued the publication of the "New England Ahnanac."

--Another son, Celadon Leeds, inventor, born in Centre Groton, Connecticut, 18 July 1818; died in New London, Connecticut, 13 October 1866, was a merchant in New London, and from 1854 till 1861 was employed in the interior department at Washington. He conceived the idea of applying the principle of the clarionet to a large trumpet, to serve as a fog signal for mariners.

--Another grandson of Nathan, Charles Miner, inventor, born in Groton, Connecticut, 14 October 1823, was trained as a practical mechanic in the works of the Wilson manufacturing company, New London, of which he rose to be superintendent. He is the inventor of the cast-iron bell-bottom jack-screw bar rel, now in general use throughout the world, for raising buildings and other massive objects, and of a lathe for cutting the thread of jack-screws, which has been in successful operation for twenty-five years, as has also his oval slide parallel bench-vise. He has invented also a breast-drill, a self-centering brace for bits, a mowing-machine, and the Daboll bushing. He developed his cousin's suggestion of a steam fog-trumpet, consisting of a steel reed vibrating within a horn, using a hot-air engine to force cold air by means of an air-pump into a boiler, from which it escapes into the horn through a valve, causing the vibrations of the reed, which are regulated by an automatic cam. He has held various local offices, and in recent years that of U. S. government inspector, for Connecticut and Rhode Island, of boilers on steam vessels.