30 THE MICROSCOPE. 



bad and Bilin in Bohemia, much used as an 

 admirable polish for metals and jewels, is seen, 

 under the Microscope, to consist chiefly of the 

 silicious cases of Diatomacese. What an idea 

 may we form of the immensity of life dis- 

 covered by the Microscope, when we are told 

 that the size of some of these silicious crea- 

 tures is no greater than a^Veth f an mcn 

 that in the tripoli, or polishing slate from 

 Bilin, a cubic line contains, in round num- 

 bers, 23,000,000 (23 millions) of the Diatom 

 called Gaillonella distans ; and a cubic inch, 

 41,000,000,000 (41 thousand millions:) 1 that 

 in a single grain of this polishing slate there 

 are 187,000,000 (187 millions) of these indivi- 

 duals ; or that the silicious coat of one of them 

 weighs the 187,000,000th (187 millionth) part 

 of a grain, as Sir David Brewster calculates; 2 

 or as Sir Charles Lyell puts it, that at every 

 stroke we make with this polishing powder, 

 perhaps tens of millions of perfect fossils are 

 crushed to atoms ! 3 



1 Owen's Compar. Anat. vol. i. p. 48. 



2 Encycl. Brit. Art. Microscope, vol. xiv. p. 805. 



3 Ly ell's Elementary Geology, p. 25. 



