WILLIAM PETIT TROWBRIDGE. 399 



currence reached this country by steamer. In 1856 he left the Coast 

 Survey, and became Professor of Mathematics in the University of 

 Michigan; but in 1857 he returned to the Coast Survey as Scientific 

 Secretary, residing in Washington, D. C, retaining this position till 

 1862. Before the civil war he established the first permanent ob- 

 servatory in this country for the automatic registration of magnetic 

 variations at Key West, and also prepared for publication the results 

 of the exploration of the Gulf Stream. At the beginning of the war 

 he was called upon to prepare a minute description of the harbors, 

 inlets, and rivers of the southern coast, from Delaware Bay to Gal- 

 veston ; and also to determine whether Narragansett Bay would be a 

 suitable location for a navy yard station, or not. 



During the rest of the war he had charge of the branch office of the 

 War Department in New York City, and acted as agent in the supply 

 of material, and as constructor of local fortifications. He built the 

 forts at Willett's Point and on Governor's Island, and made the 

 repairs of Fort Schuyler. 



From 1865 to 1871 he was Vice-President of the Novelty Iron 

 Works, New York, of which Mr. Horatio Allen was President. The 

 latter had been the first to introduce the locomotive in America, in 

 1829. He had also designed the early American locomotives run in 

 South Carolina, and the Novelty Works had designed and constructed 

 the first Transatlantic steamers of the Collins line; and during the 

 civil war they had a great deal to do in the construction and alter- 

 ation of vessels and machinery. During his connection with these 

 works he carried out a series of experiments to determine the water 

 consumption per horse power per hour of a series of steam-engines at 

 different points of cut-off. These experiments were among the earliest 

 of their kind, and led the practice of engine builders for years. 



From 1871 to May, 1877, Mr. Trowbridge was Professor of 

 Dynamic Engineering in the Sheffield Scientific School of Yale Col- 

 lege, where he built up his new department, and planned and con- 

 structed the new Sheffield Hall in which the engineering instruction 

 is given. 



From 1877 until his death, in 1892, he held the Professorship of 

 Engineering in Columbia College, New York. There were added to 

 the courses as they existed before his incumbency, successively, courses 

 in thermodynamics, dynamics of machinery, and water supply engi- 

 neering, while the engineering courses already existing were enor- 

 mously developed. In this he was aided by Professors F. R. Ilutton 

 and H. S. Monroe. 



