various parts of Scotland. ASS 



constitute them, and that the language of Nature is often as in- 

 telligibly ppoken in the minute space of an inch, as in the immensity 

 of a mountain. It is scarcely necessary to add, that the other prevail- 

 ing theory, that of aqueous formation, supposes the substances which 

 constitute this rock to have been crystallized from a watery solution, 

 and j:hat the fundamental objection to the igneous explanation, is 

 the apparently chemical impossibility, that of a rock compounded 

 of two crystallized substances, the one which is fusible at the lowest 

 temperature, and therefore would be the last to crystallize, should 

 by crystallizing first, have made its impression on the other. An 

 analogy has, I know, been offered in explanation of this difficulty, 

 but it will immediately be seen that it is at least incompetent to 

 explain the particular case under review. 



The first specimen which I have to describe is a detached crystal 

 of a flattened and irregular figure. It has been broken into four 

 parts, by transverse fractures, which have again united without the 

 intervention of any intermediate substance. Previous to this re- 

 union however, they have all been slightly shifted, in such a way 

 that the several parts of the fractures project, and the whole crystal 

 has undergone a slight deviation from its original straight line. If 

 it be alledged that this appearance could arise from a disturbed 

 crystalfization, the next specimens will remove any doubt on this 

 head. 



In these, the crystals have not only been fractured in the same 

 way, across their axes, but the fractures are filled by the quartz and 

 felspar which constitute the body of the rock. The granite veins 

 of Arran do not show more clearly the ramification of a central 

 substance through the fractures of the neighbouring rock, than 

 the^.e specimens show the veins of quartz proceeding from the 

 mass, and penetrating every fissure which had been formed in the 



Vol. II. 3 i 



