Geology and Mineralogy. 63 
and fluid bodies must be ascribed to the samé cause, and are in 
conformity with the fact that in flint glass the increase of the 
with heating when great wave lengths are employed, and in- 
creases when small wave lengths are used. The author discusses 
10. Aurora Borealis.—In a recent paper read before the Royal 
Society, Mr. Warren pe 1A Rue and Mr. Hueco W, Mirier 
stated their conviction that at the height of 37°67 miles above 
9 
Il. GroLtogy AND MINERALOGY. 
1. Report on the Geology of the High Plateaus of Utah, with 
Atlas; by C. E. Durron, Captain of Ordnance, U. 8. A., U. S. 
