94 W.P. Headden — Columbite and Tantalite. 



analysis of one crystal, not even an approximate estimate can 

 be made of the composition of an adjacent one. 



Of the following analyses, I— VIII, were of specimens from 

 the Etta mine. 



Some notes about the individual specimens analyzed are 

 here added : 



I- VIII. Etta Mine. — I. The original large piece of rock, 

 from which this specimen was broken, is now in the cabinet of 

 the University of Xew York, and this, which is an older analysis, 

 is given here because it is the only specimen having so low a 

 specific gravity which I have found at this locality. The 

 tantalic and columbic acid were separated in this analysis by 

 fusing with caustic soda and subsequently treating the solution 

 with carbon dioxide. IV. This was one of the group of 

 three crystals weighing 30J lbs. V. A large individual crystal 

 weighing 14 lbs., for which I am indebted to Dr. F. P. Carpen- 

 ter. Via and h. These are not duplicate analyses of the same 

 piece, but of what I supposed to be distinct specimens. One 

 analysis was made a year subsequent to the other. Vila. 

 Crystal weighing about a pound, the smallest of the crystals 

 forming the group, weighing 30J lbs. It seems to be inter- 

 grown with the other crystals at the base. YITb. Specimen 

 found in the collection of the late Prof. Jansen, a fragment of a 

 large crystal, showing the characteristics of the Etta mineral. 

 VIII. The third crystal in the group of three before mentioned, 

 shows but two pinacoids, 010 and 100. The upper portion of 

 the crystal is broken off. For analysis of the other crystal see 

 analysis Xos IV and Vila. 



IX. Peerless Mine. — Fragments of a crystal from a mass of 

 crystals found on the surface ; occurrence similar to that at 

 the Bob Ingersoll Mine. 



X. Cora Mine. (?) — A large massive piece, free from rock 

 having the appearance of having been broken out of a larger 

 piece. It was obtained from Mrs. Wm. Franklyn. While 

 this specimen is from another locality, and has different physi- 

 cal properties from the preceding it has the same molecular 

 ratio. 



XL Peerless Mine. — Part of the second mass found in the 

 mine, analysis No. IX was of the first piece found. They 

 resemble one another more in composition than in physical 

 properties. 



XII. Bob Ingersoll Mine. — From the mass originally de- 

 scribed by Professor W. P. Blake. The fragments show that 

 this was a large aggregate of crystals ; one piece showed a 

 crystal with fair terminal surfaces. 



XIII. Sarah Mine. — From the large mass described on 

 page 90. This and the specimen from the Cora are the 



