356 Samuel Lewis Penfield. 



the beginning of the fall term in 1881, having the title of 

 Instructor in Mineralogy, and from that time until his death 

 he was actively engaged in teaching and in extended researches 

 in this subject. Feeling the need of more advanced training 

 in certain ways, especially in methods of optical and micro- 

 scopical research, in 1884 he again went to Germany and 

 spent the summer semester at Heidelberg under Professor 

 Rosenbusch and with great benefit to his future work. In 

 1886 he assumed entire charge of the instruction in mineral- 

 ogy, he was appointed an assistant professor in 1888 and in 

 1893 was promoted to a full professorship and became a 

 member of the Governing Board of the Sheffield Scientific 

 School. 



That which Penfield accomplished during his life divides 

 naturally into two parts, the results of his investigations and 

 his work as a teacher of mineralogy. In regard to the first 

 the bibliography appended to this notice speaks far more elo- 

 quently to those acquainted with the history of mineralogical 

 science during the last quarter of a century than could the 

 efforts of any pen. Yet out of this great volume of important 

 results of work which issued from his laboratory during the 

 twenty-five active years of his life — results which have been 

 equalled in scope and value by but few men during a much 

 longer w r orking period — certain salient facts may well be men- 

 tioned to indicate his achievements. He published over 80 

 papers relating to Mineralogy and Crystallography, either 

 under his own name or in collaboration with others, besides 

 the large number which came from the assistants and students 

 in his laboratory and which were directly due to his inspira- 

 tion and oversight. Moreover this does not include a great 

 number of notes, representing crystallographic and chemical 

 work, scattered through the literature as published in the papers 

 of other workers, for Penfield was ever most generous of his 

 time and skill in helping others and he had long come to be 

 regarded in America as an ever present aid and final source 

 of appeal in problems relating to mineralogy by workers in 

 the geological sciences. 



The mere statement of the volume of his work would, how- , 

 ever, mean little unless it were taken in connection with its 



