SKETCH OF ISAAC LEA. 405 



in the conduct of a large publishing-house, and was only able to give 

 his hours of leisure to science. 



Isaac Lea was born in Wilmington, Delaware, March 4, 1792. He 

 was descended from ancestors who came over from Gloucestershire, 

 England, with William Penn, and were described as " a couple of 

 noted and valued preachers." He was the fifth son of James Lea, a 

 wholesale merchant, and was at first put in a course of classical in- 

 struction at the academy in Wilmington, in preparation for the medical 

 profession. This purpose was afterward given up, and, when he was 

 fifteen years old, Isaac was sent to Philadelphia to engage in mer- 

 cantile business in association with his brother. He had inherited a 

 strong taste for Nature from his mother, and found a congenial spirit 

 in Professor Vanuxem, then also a youth, with whom he formed the 

 habit of making collecting excursions around the city. The two com- 

 panions were soon led, by what they found and observed, to inquiry 

 into the composition and structure of the rocks ; they had to pursue it 

 at first without any guidance, but in a short time became acquainted 

 with the mineralogical collection of Dr. Adam Seybert. A diversion 

 to their pursuits was given by the occurrence of the war with Great 

 Britain in 1812. They joined a volunteer rifle company, which offered 

 its services to the Governor. Although the company was disbanded 

 without being called into service, young Lea had, by joining it, engaged 

 enough in war to violate the principles of the Society of Friends, and he 

 lost his birthright in it. Among the excursions which the two youths 

 made was one to the coal-mines near Wilkesbarre, where they found 

 slates containing mollusca, which Lea described forty years afterward 

 in the "Journal of the Academy of Natural Sciences." They walked 

 back, over the Pocono Mountain through the Wind-Gap, where Lea 

 found the first trilobite they had ever seen, and down the Delaware 

 River. In 1815 they were both elected members of the Philadelphia 

 Academy of Natural Sciences, and began to take active parts in its 

 proceedings ; and in this society Mr. Lea read his first paper, already 

 referred to, embodying the results of many years of close observation 

 which the friends had made upon the rocks during their excursions. 



On the publication, in 1818, of Professor Silliman's prospectus of 

 the " American Journal of Science," Mr. Lea procured the names of 

 fourteen subscribers to the journal an act which Professor Silliman 

 afterward declared " was the turning-point of the scheme " ; for, re- 

 ceiving such encouragement from a person with whom he had no per- 

 sonal acquaintance, he was sure the journal would be successful. Mr. 

 Lea contributed several papers to the early numbers of this journal, at 

 the editor's request ; but the article of this period which is perhaps 

 most worthy of special mention, is one that he published in 1828 in 

 the "American Quarterly Review," on the Northwest Passage, in which 

 he expressed the opinion that, if the passage were ever made, it must 

 be, as was indicated by the direction of the currents, from west to 



