Miscellan eous. 115 



oiir ideas, and especially upsets many systems ; it is one of those 

 which constitute epochs in the sciences." This memoir was followed 

 by contributions which were continued until the year 1835, In 

 1838 appeared the great work ' Die Infusionsthierchen als vollen- 

 dete Organismen,' with 64 plates, for which and for his geological 

 researches the Geological Society conferred upon Ehrenberg the 

 Wollaston medal as a special distinction. As early as 1836, Ehren- 

 berg had discovered that the polishing-powder known as tripoli 

 abounded in fossil organisms, and that the polishing-slate of Bilin, 

 near TepHtz, contained innumerable siliceous shells of similar crea- 

 tures. The same result was obtained by the microscopic exami- 

 nation of the so-called " edible earths " from various localities. 

 This occurrence of fossil organisms was soon afterwards demonstrated 

 by Ehrenberg in older formations, as is evidenced by his memoirs 

 ' Die Bildung des europaischen, libyschen und uralischen Krei- 

 defelsens und Kreidemergels aus mikroskopischen Organismen ' 

 (1839), and ' Ueber noch jetzt zahlreich lebenden Thierarten der 

 Kreidebildung und den Organismus der Polythalamien.' In the. 

 year 1841 he demonstrated the presence of organisms in the peat-beds 

 in various parts of Berlin (Museum, Eriedrichsstrasse, and Karls- 

 strasse), and gave an impulse to the technical employment of these, 

 and of the Infusorial earth of Ebstorf in the Limeburger Haide, as, 

 according to the reports of old writers, an earth serving for polishing- 

 purposes could be used for the manufacture of light building- stones, 

 capable of floating upon the water, and the dome of the mosque of 

 Saint Sophia, the celebrated structure of the Emperor Justinian, is 

 composed of such stones. With the hearty cooperation of the then 

 director of the Royal Porcelain Factory, the Mining Privy Councillor 

 Frick, Ehrenberg had stones manufactured from the Berlin material, 

 which proved from their porous nature to be very useful, and were 

 employed by the architect Hoffmann in the construction of the 

 cupola of the museum. 



In 1845, at the request of the Mining Department, Ehrenberg 

 made investigations on the diffusion of the infusorial tuffs in the 

 Eifel ; in 1847 he published his " Beobachtungen iiber Passatstaub 

 und Blutregen," in the Memoirs of the Academy of Berlin ; and this 

 was followed by a long series of papers in the ' Monatsberichte.' In 

 1840 he had prepared his ' Microgeologie,' which appeared in 1854, 

 with 41 copperplates. The first part of a continuation of this work, 

 relating specially to America, appeared in 1856. 



A new field is opened by his works on the Greensand and the illus- 

 trations of its organic life (1855), and his communications on the 

 gradually advancing knowledge of immense quantities of microscopic 

 organic forms in the lowest Silurian deposits near Saint Petersburg 

 (1852-62). His attention also was vividly excited by the recent 

 investigations of the sea-bottom ; so that, by the receipt of samples of 

 soundings from the most different regions, he was enabled to inves- 

 tigate thoroughly the microscopic organisms of the depths of the sea. 

 In 1872 he published a revision of these, illustrated with 12 plates, 

 which was followed in 1875 by a work on " die fossilen Erd- ixnd 



8* 



