402 THE POPULAR SCIENCE MONTHLY. 



SKETCH OF FKIEDEICH MOHK. 



By FREDERICK HOFFMANN. 



ON September 28, 1879, the earthly career of a man closed at Bonn, 

 Germany, whose numerous' oi'iginal researches and contributions 

 to pharmacy, chemistry, chemical analysis, geology, and other branches 

 of the physical and applied sciences, have placed him in the foremost 

 ranks of scientific investigators. Karl Friedrich Mohr was born 

 November 4, 180G, at Coblentz, on the Rhine, where his father was an 

 apothecary. After having completed the full course of the gymnasium 

 of his native city, he entered, in 1823, his father's establishment as an 

 apprentice. In 1828 he went to the University of Heidelberg, where 

 he applied himself to the study of philosophy, the natural sciences, 

 and pharmacy, and where, by the influence and guidance of Leopold 

 Gmelin, his interest was particularly drawn to chemistry ; he sub- 

 sequently studied at the Universities of Berlin and Bonn, and in 

 1831 graduated as doctor of philosophy. After having passed the 

 state - examination as apothecary, in 1832, he returned to Coblentz, 

 and became the assistant, and, in 1840, the successor of his father, in 

 business. 



Mohr's first literary production was an essay on the nature of 

 caloric and the conservation of force, published in " Baumgaertner's 

 Journal," in 1837, in which the principle of the unity of natural forces 

 and the law of equilibrium, now generally adopted, were for the first 

 time exactly and fully defined, and, five years afterward, were estab- 

 lished on a firm mathematical basis by Robert Mayer, of Heilbronn, 

 and, still later and more fully, by the experimental researches of Joule, 

 in England.* 



His application to practical pharmacy led Mohr to again enter the 

 field of pharmaceutical and chemical research ; he undertook the com- 

 pletion of the comprehensive work " Pharmacopoeia Universalis," pro- 

 jected by Professor P. L. Geiger, who died in 1836, shortly after the 

 publication of the first part of that work, embracing the crude drugs 

 and simple chemicals. The second part, by Mohr, was published in 

 1845, and contained the formulary of pharmaceutical and chemical 

 preparations of the various European pharmacopoeias in use during the 

 preceding seventy-five to eighty years, and including, of American 

 works, the United States Pharmacopoeias of 1820 and 1830, Coxe's 

 " American Dispensatory," and Ellis's " Formulary." His application 

 to the details of practical pharmacy and of chemical operations, his 

 wonderful skill and inventive mind, resulted in the improvement and 

 completion of old, and in the construction of a large number of novel 



* "Popular Science Monthly," vol. xv., pp. 397-407; ibid., vol. v., pp. 103-107; "Ar- 

 chiv dcr Pharmacie," vol. 216 (1880). 



