552 POPULAR SCIENCE MONTHLY. 



in which the writer assisted him, is not remembered, but Mather 

 declared that he was satisfied with it. Such was his occupation 

 on one of the coldest days in winter, during the whole of the 

 Saturday afternoon allowed to the corps for recreation." 



On graduating he was assigned to the Seventh Infantry with 

 the customary rank of second lieutenant. He remained at West 

 Point as acting assistant instructor of artillery during the sum- 

 mer encampment of 1828, and was then ordered to the School of 

 Practice at Jefferson Barracks, where he remained until April, 

 1829. From April to the end of June he was on frontier duty at 

 Fort Jessup, La. He was then detailed to serve as acting assist- 

 ant Professor of Chemistry, Mineralogy, and Geology in the 

 Military Academy, which duty he performed until the summer 

 of 1835. The assistant professors at the academy at that time 

 were usually detailed from recent graduates, and their terms of 

 service rarely exceeded two years. The fact that Lieutenant 

 Mather was retained in that capacity for six years indicates that 

 he was an unusually successful instructor. During the recess of 

 his course of instruction in 1833 he acted as Professor of Geology, 

 with the permission of the War Department, at Wesleyan Uni- 

 versity, Middletown, Conn., and the following year received the 

 honorary degree of A. M. from this university. In the summer 

 of 1834 he made a geological survey of Windham County, Conn. 



Within the first year after his graduation Lieutenant Mather 

 published in the American Journal of Science a paper entitled 

 On the Nonconducting Power of Water with Regard to Heat. 

 While serving as assistant professor at the academy he con- 

 tributed other papers to the same journal, and wrote a small text- 

 book, Elements of Geology, which was afterward enlarged and 

 passed through several editions. He wrote also an account of the 

 diluvium for the use of the cadets in their study of geology. 



On being relieved from duty at the academy he was assigned 

 to topographical service as an assistant to G. W. Featherston- 

 haugh in a geological examination of the country from Green 

 Bay to Coteau des Prairies. This work occupied him during the 

 latter half of 1835. He made a topographical map of the St. Peter's 

 (Minnesota) River Valley and a report, which his later associate 

 Whittlesey says he refused to present to the " pretentious English 

 geologist in charge of the expedition," but transmitted direct to 

 the United States Government. When this survey was completed 

 he was promoted to a first lieutenancy and sent to join his regi- 

 ment on frontier duty at Fort Gibson, in Idaho Territory. The 

 following summer he marched into the Choctaw country in com- 

 mand of his company. Feeling that he could now safely adopt 

 the pursuit of science as a profession, he resigned his commission 

 in the army at the end of August, 1836. 



