286 Scientific Intelligence. 



exceedingly pure, and the specific gravity of the transparent 

 crystals is 4-709 at 21° C. 



The perfection of the crystals, with their transparency and 

 color, make this occurrence of zircon one of the most beautiful 

 known. 



In a paper which we hope may appear in this Journal within 

 :i short time, we shall describe several minerals of the cryolite 

 group which occur in connection with a quartz vein in the 

 neighborhood of the zircon locality. Most of these fluorides 

 are identical with thos yolite in Greenland. 



The body of mineral found is of small extent, but yields a 

 large number of species. 



There are also several interesting species more or less closely 

 associated with the zin-on. in the study of which we are now 

 engaged. The results we hope to communicate in a future 

 number of this Journal. 

 Denver, Colorado, August 3, 1882. 



SCIENTIFIC INTELLIGENCE. 



I. Chemistry and Physics. 



!. The pmtlwttoii of electricity reyorded m the equivalence of 

 Thomson lias lately shown hy careful measurements that the 



as it becomes a general one, and shows that in certain 

 combinations all the chemical heat is not changed 

 fricity, hut only a portion, which he terms useful elect 



trical currents ] 

 zation free galv 



