Prof. Chapman's Mineralogical Notes. 



115 



Table II. — Showing the potentials in two equal spherical con- 

 ductors, and the mutual force between them, when charged 

 with quantities D and E of electricity respectively. 



XVII. Mineralogical Notes : — Second Series. By E. J. Chapman, 

 Professor of Mineralogy and Geology in University College, 

 Toronto, Canada West; late Professor of Mineralogy in Univer- 

 sity College y London*. 



1 . QTA UROLITE.—The angle of the rhombic prism in stau- 



rolite is generally stated to be equal to 129° 20'. In a 



small crystal of the common configuration, from St. Gothard, I 



have found the angle D : L (oo P : oo P oo, Naumann), fig. 1 = 

 115° 44', which gives for D:D 128° 32'. Three of the 



* Communicated by the Author. 

 12 



