156 CHLORITOID FROM KrNCARDINESHIRE. [May 1 898, 



Lieut.-Gen. McMahon congratulated the Author and also the 

 Society on the paper just read. The chemical analyses of minerals 

 in days before the systematic application of the microscope to 

 geology had often led to erroneous results, because minerals very 

 commonly enclosed endo-minerals differing materially in chemical 

 composition from themselves, the resulting analyses being thus 

 vitiated. The future of chemical mineralogy depended on chemists 

 making sure, by preliminary microscopical and optical tests, that they 

 were really dealing with a homogeneous and pure mineral. The 

 correct definition of mineral species depended on the combination of 

 the petrological and chemical methods. These methods the Author 

 appeared to have combined in his own person. 



The President and Mr, Teajll als^ spoke, and the Author 

 replied. 



