Genth.] 



388 



[Sep. 19, 



ginous and less pure ; it is associated with damourite and pattersonite. 

 It has small cavities through the whole mass. Its color is reddish. 



c. The third variety has frequently a chloritic mineral intermixed with 

 it. The lesleyite itself is fine fibrous columnar, sometimes divergent ; 

 its color is between grayish-greenish and brownish- white, and its lustre 

 between silky and vitreous. It is easily scratched by the knife, but is 

 harder than apatite. Some parts of it scratch quartz. 



Mr. Thos. M. Chatard and I analyzed the white variety a ; and Dr. 

 Koenig and I the varieties b and c ; to which, for comparison, are added 

 the analyses of S. P. Sharpless and J. L. Smith. 

 Ephesite : 



100.45 101.72 



The fusion with calcic carbonate with amnionic chloride gave me 

 10.26 per cent, of corundum. 



The oxygen ratios for RO : R 2 3 : Si0 2 : H,0 are : 

 Smith = 2.34 : 25.94 : 16.37 : 4.36 = 1 : 11.1 : 7 : 1.9 

 Genth = 2.22 : 26.20 : 16.72 : 4.55 = 1 : 11.8 : 7.5 : 2.0. 

 I have endeavored to calculate from these data the probable composi- 

 tion of this mixture, but failed. If we had any means to determine the 

 actual amount of free corundum, ichich I suppose will be between 15 and 

 20 per cent., we would propably have better success. 

 Lesleyite : 



101.38 



100.60 



100.73 



101.34 



100.76 



99.79 



