514 THE POPULAR SCIENCE MONTHLY. 



The acquisition of another kind of power by water under 

 such conditions was exemplified by the conversion of pine-wood 

 into a bright and hard black substance resembling anthracite, 

 and consisting simply of carbon associated with small quantities 

 of volatile substances. It was shown, by its granulation in small 

 globules, to have passed, in the water, through a kind of fusion. 

 The reactions from which these products resulted are all the more 

 interesting because they were obtained with a very small quantity 

 of water, hardly equal to a third of the weight of the metamor- 

 phosed glass. Furthermore, the new products crystallized at a 

 temperature considerably lower than their point of fusion. It is 

 thus proved that water highly superheated acquires an energy 

 that was unknown to belong to it. It destroys combinations that 

 were reputed to be stable, and in the presence of which it was re- 

 garded as inert; and it composes others, among which are the 

 anhydrous silicates. The production of these silicates in the crust 

 of the earth escapes our observation, because it requires a tem- 

 perature greatly superior to that of boiling water. But it must 

 be going on in the depths of the rocks, where there is no lack of 

 imprisoned water, nor of temperatures and pressures incompara- 

 bly higher than those of our most potent experiments. It is hardly 

 necessary to say more concerning the application of these syn- 

 thetic results to questions concerning the metamorphic transfor- 

 mation of entire regions. 



Other facts in nature are explained in these experiments. 

 First, they teach us the origin of quartz in the crust of the earth, 

 where it appears everywhere and in the most diverse bearings. 

 Have not the veinlets of this mineral, for example, which traverse 

 quartzites and phyllads in every direction, probably separated 

 themselves at the expense of the incasing rock, and in the pres- 

 ence of water and heat, just as the quartz was extracted from 

 glass ? An action of the same kind is recognizable in the metal- 

 liferous veins. Sometimes the temperature there is high enough 

 for the silicates also to be generated. The veins in which the 

 green emeralds of Peru are found associated with crystallized 

 quartz, calcite, and pyrites are evidently of aqueous formation. 



Thus, by going back to ancient periods, we have seen how nu- 

 merous species of minerals are produced concerning whose ori- 

 gin the observation of facts occurring to-day can not inform us. 

 These numerous minerals, whether metalliferous or stony, occur- 

 ring in various formations, are the final result of the work of 

 water, which is found in some way stereotyped in them. We 

 have thus succeeded in discovering the intimate operations of 

 that liquid in laboratories which it abandoned long ago, in fis- 

 sures of greater or less magnitude, and in blisters or the simple 

 pores of the rocks. We are instructed concerning the manner in 



