Allen and Clement — Role of Water in Tremolite. 115 



Diopside from Ham Island, Alaska. — This mineral was 

 intergrown with the tremolite from the same locality, and like 

 it was very pure. A specimen finely ground for analysis had 

 the composition : 



Cal. for CaSi0 3 MgSi0 3 



Si0 o :._ 54-65 55-6 



Fe o 3 -13 



CaO .___ -_ 25-27 25-9 



Mo-0 18-78 18-5 



K 2 0._. -07 



Ka,0 -03 



H 2 3-45 



100-38 1000 



This material being exhausted, another hand specimen of 

 the same lot was crushed to lfi mesh, separated from a little 

 tremolite and calcite by methylene iodide and benzene, and 

 dried at 105°. On blasting it lost 1*01 per cent. The dehy- 

 drated mineral was entirely homogeneous and the optical prop- 

 erties remained almost unchanged. The formation of bubbles 

 was evident, but they were less numerous than in tremolite. 

 The curve of loss to 800° was as follows : 





Table VIII. 





Time 



Charge, 3 grams 

 Temperature 



Total loss in mg. 



lOf hours 



400 



3-7 



39| " 



600 



18-3 



12 " 



800 



24-9 



The water lost was thus 82 per cent of the total water. 



Beryl from Alexander Go., JV. C. — An analysis of this 

 specimen was not made. The material for experiment was 

 taken from a single transparent crystal which contained a 

 little muscovite, but hardly more than traces. The beryl was 

 crushed to 100 mesh because it was anticipated the dehydra- 

 tion would be slow and the smaller grains would facilitate its 

 escape. The loss in weight on blasting was found to be 2*54: 

 per cent. By absorption with calcium chloride, the water 

 being liberated by fusion with soda, the quantity found was 

 2*67 per cent. The mineral after it had been blasted was 

 microscopically examined and found to possess all the proper- 

 ties of beryl. The bubbles formed were numerous and con- 

 spicuous. After the mineral had been heated a comparatively 

 short time at 400° it reached constant weight, the loss being 

 3*l mg . At 800° the loss continued over a long period without 

 showing any signs of ceasing. The results follow : 



