4 The American Geologist. January, 1592 
and pure minded man to the charge of lack of tenacity, but those 
whose cause he refused to espouse although he thought it just, gave 
him credit for a higher motive for his action. As an instance of 
the extreme delicacy of his vision, by a single glance through a 
glass case in one of the great University museums of this country 
he detected as imitations a number of specimens of so-called quartz 
which had been purchased, examined, and mounted by the pro- 
fessor of mineralogy as genuine. When these specimens were 
removed from the case and carefully tested it was found that those 
and only those which he had indicated were artificial. 
He has told us of the prosecution of his study of Rhizopods 
when he expected an Ameeba-like mass to break into two, or an 
enveloped diatom to be extruded, and the patience and endurance 
required to keep the eye at the instrument for hours waiting fora 
change that would occupy but a few seconds. He would wait and 
would see the phenomenon while a student with much more time 
at his disposal would have grown tired and missed it. 
In the Brazilian department of the Centennial Exposition were 
many valuable tourmalines, diamonds, topazes and beryls together 
with a large amount of nearly worthless material. This was put 
into the hands of the writer for determination and arrangement. 
He well remembers the glance of Dr. Leidy at a large mass labeled 
beryl and his suggestion that it be more closely examined to de- 
termine if it were not a white topaz. The size of the specimen as 
well as its color had deceived the American geologist who had 
shipped it from Brazil,and the writer. But subsequent investigation 
proved it to be in fact a white topaz and the largest then known. 
Dr. Leidy was a rare example of a simplicity of character 
which neither adulation nor adversity could tarnish. 
In his very early life a less sincerely devoted student of science 
would have had his head turned by his rapid promotion, by the 
unusual confidence and liking of his superiors, and most of all by 
the extraordinarily flattering attention of the social world, but he 
was not spoiled. Tle probably noted his sensations on those oc- 
‘asions as so many psychological experiences. 
Scientific men in all countries, very generally despise conven- 
tionalisms of dress, conversation, and carriage and there is a cer- 
tain external resemblance between them all. Dr. Leidy was one of 
the best American representatives of the scientific class in all these 
respects. A splendid head with kind expression, set upon broad 
stooping shoulders, a deep chest to which an arm generally pressed 
