34 THE EYE 



stances. Innumerable examples of the kind could be 

 furnished. 



Still more striking is the importance of the microscope 

 in mineralogy and geognosy. Here it affords us an entirely 

 different and more accurate acquaintance with the peculiar 

 nature of whole systems of rocks, of vast formations, or 

 individual mineral substances an acquaintance such as 

 these sciences could not hitherto give us. Formerly, in 

 the mountain-chains which stretch along Western Asia, 

 girdle the north of Germany and France, and again appear 

 in the Grecian Archipelago, we only saw a shelly mass of 

 carbonate of lime which, from its peculiar condition, we 

 called chalk ; in the tripoli, mountain-meal, &c., finely- 

 divided silex ; in dysodil, only a mixture of silex and 

 bitumen ; and in most opals and flints, only denser, glass- 

 like silex; but Ehrenberg's microscopic researches have 

 laid open to us a wholly new world, full of life. We find 

 the origin of no inconsiderable portion of the firm crust of 

 our planet dependant, in the most remarkable manner, for 

 its peculiar form, on the life of animals so small that they 

 are invisible to the naked eye, which, by their almost 

 miraculous rapidity of multiplication, make up through 

 absolute number and the indestructibility of their remains, 

 what they want in magnitude. 



Certain of the Infusoria consist wholly of a gelatinous 

 animal substance ; but besides these, there are other kinds 

 which, like snails and cockles, are enclosed in firm shells of 

 the most elegant forms, which are composed either of car- 

 bonate of lime or silex. The dead animal itself soon decays, 

 but the dwelling which it had built itself, the shell, remains, 

 and in circumstances favourable to the life of the animals, 

 these shells accumulate to such an extent, that whole 



