670 THE POPULAR SCIENCE MONTHLY. 



geological and ethnograpliical collections, the geographical and mete- 

 orological observations, and other results of the expedition. 



Considering such material mainly as requisite means for investiga- 

 tion and for comparative study, Ehrenberg now applied himself with 

 unceasing zeal and diligence to his rich collections, assisted by eminent 

 scholars and artists, for the illustration of microscopical objects. The 

 results were published during the years 1828-1830, in a volume 

 entitled " Scientific Travels through Northern Africa and Western 

 Asia, by Ehrenberg and Hemprich," and in a series of elaborate, strictly 

 scientific works, written in the Latin language, with more than eighty 

 splendid illustrative plates, the principal ones being the following : 

 " Symbolae physica?, seu icones et descriptiones mammalium " (1828), 

 "Symbolfe physicse avium" (1828), " Symbolfe physicas insectorum " 

 (1829-1834), "Symbols physicjB animalium evertebratorum sepositis 

 insectis " (1829-1831). 



The continuation of these consummate researches and labors was 

 interrupted for about one year, when in 1829 Alexander von Humboldt, 

 Ehrenberg, and Gustav Rose, on invitation of the Russian Government, 

 undertook an expedition to the Ural and Altai regions, with the special 

 aim of exploring their mineral resources. After the return from this ex- 

 ploration, Ehrenberg entered upon the most fruitful epoch of his labors 

 and career : he accepted a professorship at the Berlin University, but 

 still continued his original researches with unceasing assiduity. His 

 first publications had already attracted the attention of the learned 

 throughout Europe, and secured for the young investigator a reputation 

 among the remarkable array of savants then in Berlin, \yhen that 

 severe critic, Cuvier, in 1830, presented Ehrenberg's first publications to 

 the " Institute of France," he accompanied them with these words : 

 " Ces decouvertes changent entierement les idees et renversent surtout 

 bien des systemes, elles sont du nombre de celles qui font epoque dans 

 les sciences." 



The continuous series of publications fomided on and recording his 

 discoveries and researches, had reference principally to such problems 

 and objects as the phosphorescence of the ocean, corals, fossil as well 

 as living deposits of minute organic remains in the strata of the earth's 

 crust, the minute organic life in the atmosphere, the phenomena of 

 blood rain and snow, dust-showers and the " Bleeding Host," which 

 latter one, during the middle ages, was the cause of the most barbarous 

 excesses of the Inquisition. All these investigations and works were 

 followed by his splendid exploration, beginning with 1840, of the 

 minute organic creation, and by the disclosure of the influence of that 

 " realm of httleness " in the development of the present condition of 

 the earth's crust, and on the whole organic life of nature. 



In consummate generalizations he laid down the results of his life- 

 long, profound, and comprehensive observations and researches in the 

 most famous of his many works, " Microgeology " (1854). Henceforth 



