156 CYTOLOGY. 



place comes sulphur, and the sulphuretted ores originate, 

 e. g. the bisulplmrets of iron, blendes, glance-ores. 



741. Lastly, every combination or influence of the 

 other elements and mineral-classes vanishes ; acids, oxy- 

 gen and sulphur are no longer generated in the perfectly 

 dark depths, and the ore stands there in its entire iden- 

 tity, homogeneous, resplendent and heavy as the sterling 

 metal. The same results from sublimation. The heavier 

 metals remain below, the lighter ones and the sulphur 

 ascend. 



742. As the orders of earth are placed in the veins, 

 so also are the different metals themselves ; for the cause 

 of genesis is alike in both. 



743. The earth-like inetals, as iron, manganese, &c. 

 which occur constantly oxydized, are usually found upon 

 the surface of the planet ; the hydroid or water-like, as 

 lead, tin, lie usually deeper ; the aeroid or air-like, as 

 arsenic, zinc, exhibit pretty nearly the same relations as 

 the sulphur metals; lastly, the pyroid or fire-like, e. g. 

 the noble metals such as gold and silver occur frequently 

 in great depths and not unfrequently in granite ; the two 

 preceding metals generally occur in gneiss, but the first 

 even in younger or more recently formed rocks. 



744. As a certain regularity prevails in the arrange- 

 ments of ores and of metals in the veins, so also does 

 this hold good in respect to their distribution over the 

 planet. 



745. The more the polar earths are separated and de- 

 posited in the broad valleys exposed to light, by so much 

 the more in quantity and of greater purity is the ore 

 produced in its own valleys of darkness. The first ef- 

 fect, however, happens through the power of the sun ; 

 the more powerful therefore its influence, although in- 

 direct, so much the greater in quantity and purity is 

 ore produced in the depths. The greatest quantity 

 of ore and that of the noblest kind was inevitably 

 generated beneath the equator. There also more lime 

 as well as more salt are probably found upon the sur- 



