Mr. J. Taylor on Manganese Ore containing Silver, 279 



of Rutile to be imbedded in this plane, they will lie in direc- 

 tions perpendicular to its three edges and to the axis of the 

 rhomboid. 



The other case is the regular coating of some of the crystals 

 of felspar from Bavaria with cleavelandite. The coated planes 

 are the M, z, and /, of Hauy, or the M, Kl, and 2, of Phillips, 

 and the crystalline striae of cleavelandite lie in lines parallel 

 to the edge between M and L of Hauy, or M and Kl of 

 Phillips. 



In the first and third of these instances the crystallographic 

 axes of the combining bodies are parallel. In the second 

 they are perpendicular to each other, the primary form of 

 Rutile being a square prism. FT T R 



LVII. On Peroxide of Manganese containing Silver, from 

 Mexico, By John Taylor, Esq., F,R.S,y Treas, GeoL Soc, 



To the Editors of the Philosophical Magazine and Journal, 

 Gentlemen, ^ 



T AM not aware that any ore of manganese has been noticed 

 ■■- as containing silver, and I shall be glad to know whether 

 is combination is a new one or not. 



Some time since Captain Rule informed me that manganese 

 had been discovered in the Santa Ynez vein in Real del 

 Monte, and that it contained silver enough to be profitably 

 extracted by smelting. 



I requested him to send me some specimens, which I have 

 received ; they are similar in appearance to the common per- 

 oxide of manganese found in this country. 



By an assay made of an average sample by Mr. Percival 

 Johnson, it was found to contain silver at the rate of 12oz. 

 16dwts. 16grs. in the ton. 



By a more complete analysis of the mineral the same gen- 

 tleman found its composition to be as follows : 



Peroxide of manganese 30*6 



Oxide of Iron 12*5 



Silica 21-0 



Alumina 17*6 



Lime 1*2 



Water 16*7 



Silver and loss *4 



100- 

 Another mineral found in the same vein, which the Mexicans 



