OF SULPHATE OF STRONTIAN. 



301 



beg leave therefore, to offer to the Academy a more 

 accurate description of these crystals. 



Fig. 3. 



Fig. 1. 



E 



/ 



p 



/ 





A 



M 



M 



/ 





/ 



Fig. 2. 



Primitive Form. A straight prism, with rhom- 

 boidal base, of which the angles are 104° 48' and 

 75° 12' fig. 1. 



Sulphate of Strontian, trapezienne , p 



^g. 2. the inclination upon the faces are of o upon P 

 128° 31' ; of o upon o 77° 2'; of o upon the return- 

 ing face 102° 58' ; of d upon d 101° 32'. 



Sulphate of Strontian, epointee »• , p 



fig. 3. The former variety having the solid angles 

 deeply truncated, forming faces parallel to the sides 

 of the primitive rhomboidal prism. The inclination 

 of M upon M is 104° 48' ; that of the other faces co- 

 incides with the incli nations of the trapezienne. 



