4 o2 THE POPULAR SCIENCE MONTHLY. 



many parents might mistakenly have done, to divert him from 

 this to a more " practical " line of pursuits, he fitted up for him 

 a well-furnished chemical laboratory and workshop; and this 

 laboratory was through all his life a favorite retreat of Carvill 

 Lewis's, to which it was his delight to introduce his scientific 

 friends. His interest in mineralogy and geology assumed a more 

 definite and controlling shape when he was about twelve years 

 old, when Dr. Isaac Lea gave him some specimens as the founda- 

 tion of a collection, and stimulated him to go on studying them. 

 A year later he and some playmates formed a scientific society, 

 which continued in existence and of which he remained a member 

 till 1875, when it disbanded. Having been graduated from the 

 University of Pennsylvania in 1873 with the highest honors in the 

 classical course, he took a post-graduate course of three years in 

 the natural sciences. For several years after his graduation he 

 divided his time almost equally between geology and astronomy. 

 Twenty-nine communications by him are recorded in the " Pro- 

 ceedings of the Mineralogical and Geological Section of the Acad- 

 emy of Natural Sciences of Philadelphia," from 1877 to 1879. He 

 gave to the American Association in 1877 a description of an 

 aurora and of the zodiacal light as observed by him in May of that 

 year, and notes by him on the zodiacal light were published in the 

 "Proceedings of the American Association" and in the "Ameri- 

 can Journal of Science " in 1880. In 1879 he joined the Geological 

 Survey of Pennsylvania as a volunteer member, and continued 

 associated with it till 1884. In connection with this work he in- 

 vestigated the surface geology of the southern part of the State, 

 and began the tracing of the great terminal glacial moraine with 

 which his name is most closely associated, determining its course 

 through the northern part of Pennsylvania. In all these re- 

 searches, as well as his studies in mineralogy and petrology — not- 

 ably in those relating to the diamond and to the archsean rocks — 

 he was moved by an earnest spirit of independent inquiry, and 

 afforded a living illustration of the force and application of his 

 motto, " Truth for authority, not authority for truth." The con- 

 trolling force of this principle in his life-work is emphasized in 

 the simple record on his tombstone in Walmsley church-yard, 

 Bolton, " He loved the truth." 



In 1880 Mr. Lewis was elected Professor of Mineralogy in the 

 Academy of Natural Sciences, Philadelphia ; and in 1883, Pro- 

 fessor of Geology in Haverford College. He held both of these 

 positions at the time of his death. From 1885 to 1887 he was occu- 

 pied during the winters in petrologic studies in Heidelberg with 

 Prof. Rosenbusch, and during the summers in field-work on the 

 glacial geology of England, Wales, Ireland, Switzerland, and 

 northern Germany. The winter and spring of 1887-'88 were 



