692 THE POPULAR SCIENCE MONTHLY. 



himself to form the North Hempstead Library Association and 

 Library. In 1792 he was appointed Professor of Chemistry, Natu- 

 ral History, and Philosophy in Columbia College, where, while 

 dissenting from some of the principles of the French chemist, he 

 introduced, for the first time in the United States, the chemical 

 nomenclature devised by Lavoisier. His dissent from Lavoisier 

 led to a controversy with Dr. Priestley, at the end of which the 

 two disputants found themselves on a footing of mutual esteem 

 and warm personal friendship. He records himself in 1794 as 

 having exhibited at full length, in a printed essay, the actual state 

 of learning in Columbia College. At about this time, too, he was 

 co-operating with Chancellor Livingston and Simeon De Witt in 

 the establishment of the Society for the Promotion of Agriculture, 

 Manufactures, and the Useful Arts, before which he delivered his 

 first public address. Having executed a commission from this 

 society for that work, he made a detailed report, in 1796, of geo- 

 logical and mineralogical observations on the banks of the Hud- 

 son, for coal, etc. a performance which, he mentions, was respect- 

 fully quoted by Count Volney. This was the first work of the 

 kind undertaken in the United States, and the report helped to 

 secure a wide European as well as American reputation for the 

 author. Referring to it, Dr. J. W. Francis says, " He may fairly 

 be pronounced the pioneer investigator of geological science 

 among us, preceding McClure by several years." The report was 

 published in the Medical Repository, a quarterly magazine begun 

 in 1797 by Dr. Mitchill, with Drs. Edward Miller and Elihu H. 

 Smith, and continued by Dr. Mitchill for more than sixteen years. 

 After his marriage, in 1799, to Mrs. Catharine Cock, which 

 brought him the enjoyment of an ample fortune, Dr. Mitchill 

 was able to devote himself entirely to scientific and public occu- 

 pations. Among the scientific works with which he accredits 

 himself during the few years succeeding this event is the publica- 

 tion of a chart of chemical nomenclature, with an explanatory 

 memoir, in which he contended that metals in their malleable 

 and ductile state are compounds of a base with hydrogen (phlo- 

 giston), as in their calciform state they consist of a base with 

 oxygen ; and that in several there is an intermediate condition in 

 which there is no union either with hydrogen or oxygen. And 

 he extended the same doctrine to the greater part of inflammable 

 bodies. In 1802 he records a correspondence with Albert Galla- 

 tin, Secretary of the Treasury, on a project for illuminating the 

 lighthouses of the United States with inflammable air. In 1806 

 he wrote the introduction to the American edition of Assalini's 

 Observations on the Plague, Dysentery, and Ophthalmy of Egypt ; 

 and in the ensuing winter translated from the Latin Lancisi's 

 book on the noxious exhalations of marshes at Washington a 



