434 THOMAS HILL. 



Ann (Pope) Shepard, of Dorchester. In this new relation there was 

 every promise of happiness for him and for his children; hut she early 

 hecame an invalid, and died in 1869. 



Dr. Hill's sons are Henry Barker (H. U. 1869), Professor of Chem- 

 istry in Harvard University; Thomas Roby, in business in Phila- 

 delphia; and Otis Shepard, only child of his second marriage. Of 

 his four daughters three are married, respectively, to Lewis Pierce 

 (Bowdoin College, 1852, LL. B., H. U. 1855), of Portland, Alfred 

 Worcester (H. U. 1878), M. D., of Waltham, and Robert H. Monks. 



Dr. Hill was, in a certain sense, unique, — the only man of his kind 

 that I have ever known. There was, perhaps, no department except 

 mathematics in which he had not his superiors, and there are men 

 who have covered superficially as wide a range of science and knowl- 

 edge as was within his scope ; but the omniscience which was said 

 to be Lord Brougham's foihle was his special gift. He not only 

 knew something in every department, but there was none within his 

 reach in which he was not so conversant with principles, truths, and 

 facts that he seemed the peer of an adept, and amply qualified to be a 

 teacher and guide. While as a mathematician he was well known as 

 second to no man of his time, there might be named several other de- 

 partments in either of which, had it been his specialty, he would equally 

 have held an unrivalled eminence. 



In mathematics his earliest publication was an " Elementary Trea- 

 tise on Arithmetic," designed for pupils of an advanced grade, as an 

 introduction to Professor Peirce's series of text-books. This appeared 

 in 1845. In 1850 he published an " Elementary Treatise on Curva- 

 ture," and a " Fragmentary Essay on Curves." These works marked 

 the early stages of a series of investigations on curves, in which ho 

 performed no small amount of original work, the results of which are 

 somewhat densely strewn in successive records of proceedings of 

 scientific bodies. His attention was specially directed to the curves 

 of nature, those that are found in the various forms of organic life, all 

 of which he believed to be capable of expression by equations in the 

 terms of their co-ordinates, and for not a few of which he determined 

 the equation. In one of the papers to which we refer he described 

 and defined an entirely new curve to which he gave the name of the 

 " Tantalus." 



In 1855 he published his " First Lessons in Geometry," followed 

 shortly afterward by a " Second Book." The first of these was de- 

 signed to create in the child an interest in form and figure by appeal- 

 ing to the imagination, and it made him acquainted by the eye with a 



