Genth and Vom Rath.] dOO * [April IT, 



Deducting the admixtures the pure mineral contains : 



Atomic ratio. 

 CI = 2.18 = 0.061 = 1 



AsA = 10.73 = 0.047 1^0 090 _14g 

 VA =7.94 =z 0.043 i 



PbO = 79.15 = 0.355 = 5.82 



100.00 



The small excess of lead is evidently owing to an admixture of cerussite. 

 and the mineral is a combination of one molecule of mimetite with one 

 molecule of vanadinite = PbiClCAsO^la + PbjClCVOJj, corresponding 

 to which is the following : 



100.00 



The name has been suggested by Mr. N. H. Muhlenberg in honor of 

 Dr. F. M. Endlich, Superintendent of the Sierra Mines at Lake Valley, 

 N. M. 



Since the above has been written Mr. Muhlenberg sent a new supply ot 

 endlichite which was diflferent in appearance from that previously sepn. 

 It consisted of groups of crystals of a columnar structure, some radiating 

 from a centre and also forming sheaflike aggregations. In many of them 

 the hexagonal form could be distinctly seen, especially towards the diverg- 

 ing ends which show the basal plane and pyramid very distinctly. They 

 are all strongly ^riated. The individual crystals are white and yellowish- 

 white or s'traw-yellow, towards their terminations often changing to yellow 

 and in a few groups to a deep orange red. The largest groups were 10™" 

 in length. 



The whitest gave a spec. grav. of 6.864 and contained : 



= 0.336 



100.77 

 From this the ratio of the constituents appears to be about the same as 



