316 THEORIES OF ORE DISPOSITION HISTORICALLY CONSIDERED. 



with some open spaces, which being afterwards filled, would form 

 mineral veins. "" Where a vein has been cut or deranged by a visible 

 rent," he remarks, " it is again to be met with by following the 

 direction of this last." 



Charpentier was a careful observer and a very cautious theorizer. 

 He says, " Natural history will always gain more from true and 

 accurate descriptions of her phenomena than from many and yet too- 

 early explanations otfered for them '' — a most excellent principle 

 which he admirably carries out in his own work. He presents many 

 arguments derived from his own extensive observations in mines 

 against the prevalent theory that veins were once open cracks formed 

 by contraction, and that they had been filled by material flowing ill 

 from the surrounding rocks and hardening in them. Some of his 

 objections were : 



That contraction could not have made the kind of fissures that the 

 veins are found to fill. 



Open or empty spaces could not have existed under the conditions 

 present when they were formed ; pressure would have closed them. 



The fragments of country rock as foinid in veins could not thus be 

 accounted for. If they had simply fallen into an open crack, they 

 would have accumulated at its bottom. 



The comparatively uniform arrangement of ore in the vein, the 

 enrichment caused by the crossing of one vein by another, the tran- 

 sition from vein material to country rock, etc., could not be explained 

 on the contraction theory. 



Having given his reasons why he believes that veins are not the 

 filling of w4de open spaces in the rocks, he says his readers will natu- 

 rally ask how he supposes them to have been formed, and although he 

 is not anxious to j^resent a theory, he says he can not see from his 

 observation of the workings of nature any other method for the for- 

 mation of veins or other ore deposits than by an actual transforma- 

 tion of the rock material. Nature's processes have created innumer- 

 able small cracks and fissures in the rocks, and when a great num- 

 ber of such cracks lie together and in a conmion direction they might 

 give rise to a considerable vein deposit. Vapors bringing in mineral 

 solutions might penetrate these small cracks, as the sap rises in capil- 

 lary tubes in organic bodies. If thereby the intermediate rock mass 

 became changed into vein material, a vein deposit might be created 

 without the necessity of wide emi)ty spaces for its reception. 



Rather more than usual space has been given here to Charpentier's 

 work because of the striking contrast of his mental attitude with that 

 of his great successor, Werner, whose reputation so completely over- 

 shadowed him that he has received less notice from later writers than 

 seems to be his due. 



