COOLEY, Le Roy Clark, chemist, born in Point Peninsula, New York, 7 October, 1833. He was graduated at Union in 1858, where he followed a scientific course. From 1861 till 1874 he was professor of natural sciences in the New York state normal school, when he became professor of physics and chemistry in Vassar College. He has devised various forms of apparatus to facilitate laboratory instruction in physics and chemistry, and in 1868 invented an electric register by which piano-wires and tuning-forks leave an imprint of their vibrations, which was the first successful application of electricity to the purpose of recording swift periodic impulses in permanent characters. Prof. Cooley has contributed frequently to educational and scientific journals, and has published "A Text-Book of Physics" (New York, 1868); "A Text-Book of Chemistry" (1869); Easy Experiments m Physical Science" (1870); "Natural Philosophy "for High Schools" (1871); "Elements of Chemistry for High Schools" (1873); " The Student's Guide-Book and Note-Book" (Poughkeepsie, 1878); "The New Text-Book of Physics" (New York, 1880); " The New Text-Book of Chemistry" (1881); "The Beginner's Guide to Chemistry" (1886).