THE PROGRESS OF SCIENCE 



3* 1 



forest counties of Pennsylvania, and 

 for three years had charge of a church 

 in Milton, near Boston. There he was 

 married and there he returned to live 

 in his old age. But he was not suffi- 

 ciently orthodox for the ministry and 

 was fortunately driven back to geology. 

 In Philadelphia he became a geolog- 

 ical and mining expert. He made maps 

 of coal fields for the Pennsylvania 

 Railway and compiled an iron manu- 

 facturer's guide. He was for many 

 years secretary and librarian of the 

 American Philosophical Society and in 

 1872 became professor of geology in 



Lesley's interests were wide, being 

 by no means conrined to geology. He 

 himself says in a letter to Professor 

 0. N. Rood " I have done nothing 

 worthy of record in science." He then 

 tells what he believes his services to 

 have been — improvements in certain in- 

 struments — the odometer, the meas- 

 uring divider and the aneroid barom- 

 eter; the introduction of contour 

 curves in geological field work; and 

 two theories — the determination of the 

 present system of surface drainage by 

 the dimpled form of the plicated orig- 

 inal surface and the production of 



Peter and Susan Lesley. 



the University of Pennsylvania. In 

 1S74 the second geological survey of 

 Pennsylvania was inaugurated and 

 Lesley accepting the directorship car- 

 ried out the great work of his life, 

 though begun at the age of fifty-five 

 years. The hundred and twenty vol- 

 umes of the reports of the survey are 

 due to the men he selected for the 

 work, to his constant oversight, and 

 to his careful editing. The work gives 

 him high rank among those who have 

 done most to advance geology in this 

 count rv. 



modern topography chiefly by the un- 

 derground solution of limestone strata. 

 In 1893 Lesley's health failed and 

 he lived quietly until his death in 

 1903 at the age of eighty-four years. 

 The photograph which his friends re- 

 gard as the best is here given, and a 

 reproduction of a portrait painted in 

 the old age of her parents by Mrs. 

 Bush-Brown. 



SCIENTIFIC ITEMS 



We record with regret the deaths of 

 Dr. Friederich Kohlrausch, the eminent 



