FORMATION OF PRIMITIVE MOUNTAINS. 337 



The importance of such attempts shew the value of 

 any experiments that go to prove the formation of mi- 

 nerals by artificial means ; and Mitscherlich has been very 

 successful in detecting several mineral species formed ar- 

 tificially. 



Berzelius has shown, in his Chemical System of Mine- 

 ralogy, that the greater part of the chemical combina- 

 tions of which our Earth is composed, and especially the 

 primitive mountains, are analogous to salts and double 

 salts; and that, in these combinations, the silica, car- 

 bonic acid, and oxide of iron, act the part of acids ; the 

 silica combines with the alumina, lime, magnesia, prot- 

 oxide and peroxide of iron, protoxide of manganese, 

 potash and soda, forming, with these bases, either simple 

 salts, or double salts, in proportions determined by the 

 different degrees of saturation ; the carbonic acid is com- 

 bined with the lime and manganese, and the peroxide of 

 iron with the protoxide. 



The object which should be proposed in these at- 

 tempts, of which we speak, is to investigate the relation 

 of these bases to the three acids. We find ourselves 

 fortunately seconded in this attempt by a branch of na- 

 tional industry ; for the complete extraction of the 

 greater number of metals depends upon the relation of 

 the silica to the above-mentioned bases, the degrees of 

 saturation in which the silica may occur with them, the 

 greater or less degree of affinity with which these bases 

 combine with the silica, and, lastly, the chemical quali- 

 ties of the combination formed. It is necessary for the 

 metallurgist that he endeavour, in order to attain his 

 object completely, to produce, in proportion as the mi- 

 nerals differ, different chemical combinations of the sub- 



Y 



