conflicting— all the more so as they do not agree on opposite 

 sides of the crystal, being invariably much higher on the 

 one side than on the other. A mean of the results obtained 

 gives the angle between this face and the a pinacoid as 73° 

 46' on one side and 78° 33' on the other, which are closest to 

 A (103) and D (101) respectively. 



The Clinodomes are represented by /, f and p which are 

 present on all the crystals examined. I is smooth, narrow 

 and rectangular in shape, f is always larger than / and in 

 general is six sided and strongly striated, owing to oscil- 

 latory combination with /. p always occurs as small 

 triangular faces. 



Of the prism faces m is always very large and gives 

 excellent readings, w occurs only in a few cases and is 

 small and four sided. Of positive hemipyramids h is by far 

 the more important. It occurs as large four or six sided 

 faces, while s is very much smaller and in general rectan- 

 gular. The negative hemipyramids are represented by 

 if, k and R, they are all small faces, u being invariably 

 triangular, but sometimes four sided, while k and R are 

 four sided— k being much broader than R. 

 Type III. 



This crystal is of different order of size to Types land II, 

 measuring approximately 8 x 25 x 9 mm. in the direction 

 of the a, b and c axes respectively. In habit it is very 

 similar to Type II, inasmuch as it is elongated in the direc- 

 tion of the b axis and is prismatic. It is, however, charac- 

 terised by the presence of a large negative hemipyramid A 

 (2'18*3), and also of a very large negative orthodome D(l0J); 

 other forms present are a </> <r c r { v I f pm h s P (223). 



Figs. 5 and 6 represent a clinographic and orthographic 

 projection respectively with the b axis vertical, and the a 

 axis running right and left, a is again the largest face 

 and is very much striated. 



