viii CHANCE— BIOGRAPHICAL NOTICE OF J. P. LESLEY. [April 6, 



He was fortunate in securing as his partner for life one whom 

 nature had richly endowed with intellectual gifts of an order similar 

 yet complementary to his own. Her ability as a writer of delightful 

 domestic sketches and reminiscences enabled her to appreciate and 

 enter into the spirit of his aspirations, while the unruffled serenity 

 with which she confronted the storms of life was reassuring to his 

 more nervous temperament, soothing and allaying his fears and en- 

 couraging him to wait patiently for the fair weather sure to follow. 



In 1849 he became a member of the American Association for 

 the Advancement of Science. In 1851 he resigned his pastorate at 

 Milton to resume geological work with Professor Rogers. 



From 1853 to 1856 he was engaged in private and corporation 

 surveys in Pennsylvania, and in the latter year published his first 

 book, " Manual of Coal and Its Topography," a small volume of 

 224 pages finely illustrated by the author ; now a very rare book and 

 in great demand by geologists. That he believed this book con- 

 veyed a message of value which would add to his prestige and bring 

 clients to his office is frankly stated in the first sentence of the pref- 

 ace, beginning " The author has planted this sapling for the future 

 shade and ornament of his own office, but trusts that it may prove 

 useful also, and perhaps agreeable to the public highway." 



He was elected secretary of the American Iron Association in 

 1856, during the next two years was engaged in compiling statistics 

 of the iron trade in the United States and in 1850 prepared and 

 edited for the association an octavo volume of eight hundred pages 

 entitled " The Iron Manufacturers' Guide," which for many years 

 was a standard reference book. 



In January, 1858, he was elected librarian of the American Philo- 

 sophical Society and the next year became one of its four secretaries, 

 which dual office he held until his resignation in 1884. He was 

 elected vice-president in 1887, continuing in that office until 1897. 



In 1859 he was elected professor of mining at the University of 

 Pennsylvania, in 1872 was made professor of geology and mining, 



disposition, charitable and kindly, devoted to her husband and children and 

 always deeply interested in his work and plans, and to her affectionate care and 

 assistance must be credited his ability to turn out such enormous quantities of 

 work well done. 



