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



in this office for ten years, when faiHng health compelled him to 

 retire from active participation in the affairs of the society. 



Those to whom he was personally known, will always remem- 

 ber how earnestly, efficiently and tirelessly he labored for this 

 society " for promoting useful knowledge," how dear to him were 

 its traditions and purposes, and how faithfully he performed his 

 official duties to it. 



The promotion of useful knowledge was with him an absorbing 

 passion. He loved to impart to others what he knew, seeking 

 knowledge that he might give it to others. He had the inborn love 

 of the teacher. It was his life to him to learn that others might 

 learn and thus profit through him. He was no miser of his great 

 wealth of knowledge, but spent it prodigally that there might be 

 some for all, yet was he not denuded of it but enriched in the giving. 

 Yet was he neither haughty nor austere nor proud. He was ever 

 an attentive listener, always eager to grasp some new fact, willing 

 to ignore or disregard mere authority, if thereby he might seize 

 upon something new, something valuable, something useful to his 

 fellowmen. And even when after years of successful work he be- 

 came one of the foremost living geologists, he was still ready to 

 listen thoughtfully and appreciatively to the laborer, miner or artisan, 

 hoping thereby to learn something that might have escaped his 

 own observation. 



One may perhaps best comprehend the passion for science, for 

 research and *for scientific truth that seemed to pervade his every 

 thought and to govern his every act by reviewing what he was to 

 this society, what he did for it, and the underlying cause of his 

 great love for it, doubtless to be found in the title of the society 

 '' for promoting useful knowledge," for his whole professional life 

 was consecrated to this purpose and to a society pledged to this 

 end, his allegiance naturally was given. 



For several years he was professor of geology and mining at the 

 University of Pennsylvania, where as a student in the year 1872 the 

 writer first came to know, in common with all those who studied 

 under him, his gentle and kindly personality and his conception of 

 the value of knowledge. And doubtless many of his former students 



