Crystalline Silicide Bocks. lib 



injurious Icind, in which, unfortunately, distinguished investi- 

 gators are involved, will then be removed ; and no one, how- 

 ever great may be his name, will allow himself dictatorially 

 to stamp as ** hypotheses" or " false explanations," historico- 

 geological/ad* of the first rank. 



occurred in the cmst of the globe ; the demands might be so great that geologists 

 would not be able to satisfy them ; but in this case it is to be remarked, that, 

 after such 9i full elucidation of what had taken place, there would not be much 

 question as to an explanation, for, in this elucidation, the series of chemical 

 events would also form an element. Should, however, only reasonable require- 

 ments be made as to a history of this kind, then it is my opinion, as has already 

 been seen, that this can be accomplished, but that chemistry will be found defi- 

 cient in a greater or less degree, and especially if it will not admit of any other 

 illustrations but those obtained in the usual manner by experiment. 



The following, for example, is a fragment of geological history — pure and un- 

 disguised history — in regard to which I venture to think, that it is in all its parts 

 perfectly to be relied on. At some period or other after the strata constituting 

 our so-termed primitive gneiss-formation had been brought into their present up- 

 right position, a series of strata were deposited at the transitive epoch, which 

 afterwards were variously transmuted in a gradual manner, and at the ordinary 

 temperature. We see most of them now as clay-slates, but other portions exhibit 

 more or less crystalline masses, which occur as well in the slaty form as in the state 

 of unstratified rocks. These were developed, not quite irregularly, according to 

 their diflFerent kinds, in the transition district ; thus, in the neighbourhood of 

 Christiania, it is quite evident that always only a particular part of the masses 

 of this formation, viz. solely some of the beds which lie next the fundamental 

 rock, have been converted into a peculiar kind of porphyry ; in consequence of 

 which this porphyry is quite generally met with in the form of beds, either direct- 

 ly on the fundamental rock, or at least near it, (Gaea Norvegica, i., plate ii., fig. 

 6, 7, 8). — Now, must not the chemist, before whom this account is placed, with 

 the request that he will give an exact explanation of the act of formation of these 

 beds of porphyry, confess that the problem is beyond his powers ? But this he 

 must confess with respect to many much less important cases. Chemistry is not 

 yet in a position to explain the change produced on glass by long lying, observ- 

 ed by Brewster, and mentioned at p 172 ; a change which, it may be remarked 

 in passing, is undoubtedly analogous to that of the conversion of a more or 

 less homogeneous rock into porphyry, diorite, &c. Let it then be assumed 

 that, although the chemist be forced to make this confession, he is by no means 

 absolutely unwilling to admit as true the above historical report ; but that, on the 

 contrary, he is inclined to investigate the subject more closely, in combination 

 with the geologist ; then his reasoning will be as follows : Many things are pos- 

 sible in nature, which are not so in laboratories ; in the former case, enormous 

 masses are in operation for enormous periods of time ; in the instance before us, 

 we have to take into account that enormous apparatus which is produced by the 

 different mutual position of the beds of the two formations meeting each other ; 



