SKETCH OF ISAAC LEA. 409 



to the microscopic examination of quartz-crystals, with drawings and 

 descriptions of the inclusions and markings of each, so that Professor 

 H. Rosenbusch, in his work on the subject, mentioned him as having 

 been the first in America to enter into microscopic mineralogy. He 

 had engaged, since his return from Europe, in other branches of nat- 

 ural history than conchology. The elephant folio edition of the ac- 

 count of the fossil foot-marks near Pottsville elicited warm commenda- 

 tion for the beauty of its execution and illustration. In 1858 appeai'ed 

 a memoir on the embryology of the Unionidw, giving descriptions 

 and figures of thirty-eight species. In all of his papers he described 

 eighteen hundred and seventy -two species of mollusks of various kinds, 

 most of which were from the United States. The series was embodied 

 in a private edition of thirteen volumes, with three indexes, which the 

 author distributed among men of science and learned societies. Richard 

 Owen, acknowledging the receipt of one of the volumes, said, "They 

 represent a kind or class of labors the most genuine and important 

 and lasting, in the hard endeavor to gain a knowledge of Nature." 

 Professor Haidinger, of Vienna, said, on a similar occasion, that his 

 work would " last as long as natural science shall be cultivated by 

 mankind. The more it is compared and studied, the more appears 

 your power of observation, your efforts in pursuing your object, your 

 steadiness and perseverance." M. A. Boivin wrote, "You render a 

 great service to science in devoting your time to the classification and 

 description of the Undo." About ten thousand individuals were dis- 

 played in Dr. Lea's cabinet of Unionidw, so arranged that each could 

 be separately examined, and, in many instances, with a sequence from 

 the youngest to the oldest, so as to exhibit the aspects of growth. His 

 other cabinets contained nearly a thousand specimens of quartz-crys- 

 tals, nearly five hundred of corundum, thirty-five drawers of the mica 

 group, and several hundred sections of lamina prepared for the micro- 

 scope. 



In his ninety-fourth year Dr. Lea continued in good health, with 

 his mental and physical faculties unimpaired ; and in 1884 he was 

 able to receive and entertain about two hundred members of the Brit- 

 ish Association at his cottage at Long Branch. He was President of 

 the Academy of Natural Sciences in Philadelphia from 1853 to 1858, 

 and was President of the American Association in 1860. The list 

 given in his "Bibliography" of the society honors conferred upon 

 him numbers twenty-eight titles, and concludes with an etc. A corre- 

 spondent who maintained most intimate and confidential relations with 

 Dr. Lea for more than twenty years, furnishes a sketch of his personal 

 character and social life, from w r hich we quote the following words : 



" Possessing a mind of great vigor and culture, he was a most 

 genial companion to those whose tastes and sympathies accorded with 

 his own. He was an ardent admirer of the works of Nature ; and his 

 cultivated mind enabled him to perceive many qualities and properties 



