﻿Canadian Record of Science. 



and in general tabular in form. Some of them, however, 

 were pyramidal in habit. The crystals were secured by 

 treating the mass for several days with acetic acid. The 

 faces of some of the crystals were plane and glancing, and 

 hence gave fairly good reflections for measuring the 

 angles on the reflecting goniometer. The measurements 

 were made with the " two-circle " goniometer in the 

 laboratory of Professor Dr. Victor Goldschmidt in 

 Heidelberg. The reflections were single, though faint in 

 some cases, but by using the magnifying apparatus in 

 connection with the instrument the faces, were determined 

 beyond doubt. 



The following forms were observed :- 



c= 



'I 0001 



r = 10 



{1011} 



m= ooO -j 1010 



s = 20 \ 2021 



1 



v-40 I 4041 1 



The basal plane is usually large and sometimes in 

 combination with the prism m alone. In other crystals 

 the basis c occurs in combination with the prism m and 

 pyramid s. Fig. 1 shows an ideal top view of the crystal, 

 and Fig. 2 shows the actual form of the distorted basal 

 plane and pyramids. Fig. 3 shows the crystal in 

 perspective. Owing to distortion the crystal has a 

 somewhat rhombic appearance, but the measurements 

 show that it belongs rather to the hexagonal system. 



Laboratory, School of Mining, 

 Kingston, Ont. 



