362 Samuel Lewis Penfield. 



of work executed by him in conjunction with his students or 

 by them under his direction. The writer, who was greatly aided 

 by Penfield's instruction at the beginning of his own scientific 

 work in mineralogy, can abundantly testify to his generous help- 

 fulness and sympathetic interest in others and their work. 



Penfield gave unlimited pains and thought to perfecting his 

 material equipment for teaching and to this much of his suc- 

 cess was due. In his laboratory he had many carefully chosen 

 collections of models, of crystals and of minerals, each de- 

 signed for particular purposes, and the arrangement of these 

 and of the apparatus was carried out with a system and a com- 

 pleteness for uses of instruction that always excited the admir- 

 ation of those qualified to judge of their character. In the 

 same way with great skill and ingenuity he constructed models 

 and apparatus for use in teaching crystallography and the opti- 

 cal properties of minerals to his classes and advanced students. 

 JSi or should there be forgotten in this connection the care and 

 labor he expended in preparing the new edition of Brush's 

 Manual of Determinative Mineralogy, the additions to which, 

 dictated by his experience in teaching, are of the greatest 

 value to students. 



It was in fact a question which Penfield ever had upon his 

 mind — how he could improve his methods and equipment for 

 instruction, and as a result thej attained to so high a degree of 

 completeness and practice that many teachers of mineralogy 

 who were not his pupils found a visit to his laboratories a 

 source of help and inspiration. 



It is a matter of satisfaction to his friends that, after the 

 first attack of illness, his life was spared long enough for him 

 to realize his cherished ambition in the completing of the new 

 laboratories he had planned in Kirtland Hall and in the 

 arrangement and perfecting of their equipment. In his new 

 quarters he passed, in spite of illness, two very happy years of 

 busy work, with his students and in investigations. 



Penfield's activities were not confined to his laboratory. 

 In the middle eighties he spent two summers as assistant in 

 geological work to Professor Iddings in the survey of the 

 Yellowstone Park, and later a number of summers were spent 

 by him in northern New York, in JSTorth Carolina and Colo- 



