374 M. Berzelius's Bemarks on 



aiTived when a full description can be given of the phenomena 

 examined, and that it is therefore most natural we should con- 

 fine ourselves to the use of the facts which may enable us to 

 form the first steps to an elucidation, such as the facts may 

 be. without going into their remote causes.""* 



This first step towards the elucidation, Keilhau thinks can 

 be made by means of the known power of matter, by which 

 substances of a similar nature are attracted to each other, 

 somewhat in the same manner as in the roasting of .some of 

 the inferior copper-ores, the metal collects at certain points iu 

 the roasted mass ; and as some formless masses gradually obey 

 the power of crystallization, so that their parts approach and 

 give rise to crystals. In this manner he hopes to be 'able to 

 employ chemistry in explaining what occurred at the forma- 

 tion of the rocks, and thinl^s that, inasmuch as this science is 

 far from having reached the limits to which it may be carried, 

 it must be permitted to anticipate this extension of the science 

 by theor}', while, however, care must be taken that specula- 

 tion should assume nothing but what will probably be after- 

 wards confirmed by chemistry. Regarding these above-men- 

 tioned collecting and crystallizing powers, as princijial agents 

 in the formation of the crystallized minerals and rocks, Keil- 

 hau has sought long since to establish the following doctrine : 

 (Berzelius quotes the passage, which will be found at p. 353 of 

 this number, " that one of the hitherto known forms," &e.) 

 I shall now, in his own words, give his account of the rising 

 of granite into the transition-formation.-f* * * * ^ 



Keilhau supposes, moreover, that a similar crystallizing 

 power, at the locality Adhere the granite-forming process now 

 spoken of was developed, began to change transition-limestone 

 into marble, and his opinion as to the formation of gneiss and 

 mica-slate is, that these rocks were produced by peaceful trans- 

 forming processes, altogether analogical to that which pro- 

 duced granite and the other crystallized rocks, in which the 

 slaty or stratified structure was lost in the original materials. 



But Keilhau has not concealed from himself the difficulties 

 which present themselves in following out this theory ; one of 



* See this Journal, vol. xxv. p. 9?. 



t See tbi<5 Journal> ^t)1. xxv. p, 263 to the bottom. 



