1894 THE MICROSCOPE. 16Y 



of space tend to resolve themselves into clustering groups 

 of stars. The more we increase the power of our micro- 

 scopes, the more and more does the indefinite dust of 

 our quartz grains tend to body itself forth into definite 

 crystalline forms with individualities as strongly marked 

 as the starry worlds of space. 



The evidence of the presence of quartz grains derived 

 from Benrinnes granite is particularly convincing. That 

 the three first groups of acicular grains should be found 

 side by side in the sandstones, and in the granite is proof 

 of identity beyond the possibility of dispute. The evi- 

 dence of the presence of Ardclach granite is not so strong, 

 though it is still considerable. With regard to Kins- 

 teary, the whole case has not been stated. Let us study 

 for a little the structure of this remarkable granite, 

 which, in some respects, is very peculiar indeed. Here 

 is a section of Kinsteary granite (figure 10). The first 

 peculiarity of it is to be found in these grains which I 

 have called " cleaved grains." These I believe to have 

 been at first felspars — the original felspars of the gran- 

 ite, but at some period of its history the granite under- 

 went a process of re-cooking, when new felspars began 

 to crystallize round other centres, and in the process 

 they robbed this earlier set of their basic constituents, 

 and left them with the cleavage of felspars, but chiefly 

 composed of quartz. Then, by the pressure of these 

 young and growing felspars, their cleavage, while they 

 w^ere still in a plastic condition, was deformed and thrown 

 into irregular wavy lines (figure 11). Now, similar 

 grains occur in the sandstones from Newton upwards 

 and, as if to make assurance doubly sure, a crystal of 

 this ruby mineral, a cube of black magnetite, or a fine 

 needle, as here, is added. 



Again, as has been hinted, the felspars of Kinsteary 

 are peculiar (figure 12). They show a dark nucleus of- 

 ten containing grains of magnetite w^ith a clear margin 



