140 G. U. Shepard on Hermannolite. 



tained, and leave do room for doubt on the subject. The fol- 

 lowing is the evidence on this point thus far obtained. 



Measurements on four independent crystals gave for the 

 supplement angle made by the plane of the axes: 

 y j With e^ (§-5=203), 18° 9'; hence with basal plane, 25° 50', 

 ^' ] With 62(21=201), 45° 9'; '" " " " 25° 46'. 



ir. With 6a(f ?=205), 40° 65 ; " " " " 25° 59'. 



m. With i5(a= 100), es^-ro"; « " " « 20°-25°. 

 IV. With the basal plane, direct measurement, 25°. 



I have since made an optical examination of a crystal of the 

 third type. One single crystal of this type allowed of a stauro- 

 scopic examination. Only a small portion of it was transpar- 

 ent enough for use, but the circumstances allowed of a very 

 exact adjustment according to the method of Groth, and the 

 probable error cannot exceed one degree. The measurement 

 gave for the supplement angle between the base and the plane 

 of two of the axes of elasticity 7|°, a result which, like the cor- 

 responding one obtained for the second type, is at variance with 

 the supposed orthorhombic character of the species. The series 

 of measurements were made at different times with independent 

 adjustments, but no considerable variation was found in the 

 result, so that it may be considered as being above question. It 

 is remarkable that the coi-respondence between the two types 

 is not greater. In crystalline form the third type is between 

 the first and second. I have to regret that no satisfactory 

 material is at hand for the extension of these investigations to 

 the Vesuvian huraite. 



It may not be out of place to state here that, through the 



kindness of Mr. Cosgriff, the Yale College Cabinet has recently 



received some exceptionally large crystals of chondrodite from 



'illy-Foster Iron Mine. The crystals were quite perfect, 



and four inches or more in length. Like all the large crystals 

 they are partially altered, and have therefore little luster. They 

 are penetrated with serpentine and brucite derived from their 

 alteration. 



Art. XVII. — On Hermannolite, a new species o/ the ColumUum 

 group ; by Charles Upham Shepard, Sr., Mass. Professor 

 of Natural History in Amherst College. 



In vol. 1, p. 90, of this Journal (1870), I described as proba- 

 bly new, a Columbium mineral from Haddam, Connecticut, to 

 which in June last* I gave the name of Hermannolite, in honor 

 * See Popular Guide to the Museums of Amherst College, p. 71. 



