238 NICOLAUS STENO 



water enclosed within crystals, since it is certain that air 

 together with water is contained therein, and that many crys- 

 tals are found which enclose air alone. But if the crystal had 

 indeed grown in an aqueous fluid, all the spaces enclosed on 

 every side would be filled with water, ^ since it is an undisputed 

 fact that water kept in that way never vanishes in any number 

 of centuries. 



The cavities of the rocks, formed in different ways, as has 

 been said above, afford this place for crystals, and the fact that 

 entire hills consist of earthy substance packed with crystals, is 

 no disproof, seeing that in the vicinity of the same hills are 

 found mountains of rock suited to the formation of crystals. 

 P. 39. And in those hills of earthy matter, large unburied rocks are 

 pulled out which have been rent from neighboring mountains, 

 and some of these show fissures filled with the material of 

 marble, precisely as the fissures of strata in mountains of rock 

 are filled. The same cause, moreover, which hurled upon the 

 hills the fragments of strata rent from the neighboring moun- 

 tains, can likewise have sown over them broadcast the crystals 

 which had been shaken out from cavities of the same strata. 



The following propositions will show what can be deter- 

 mined concerning the place of the crystal to which new crystal- 

 line matter is being added : 



I 



A crystal grows while new crystalline matter is being added 

 to the external planes of the crystal already formed. No room 

 at all is here left for the belief of those who affirm that crystals 

 grow, plantlike, by nourishment, and that they draw their 

 nourishment on the side where they are attached to the matrix, 

 and that the particles thus received from the fluid of the rock, 

 and transmitted into the fluid of the crystal, are inwardly added 

 to the particles of the crystal. 



II 



This new crystalline matter is not added to all the planes 

 but, for the most part, to the planes of the apex only, or to the 

 terminal planes, with the result : 



' This would not necessarily follow. 



