288 On the Crystalline Forms of Artificial Salts. [April, 



parallel to P is very easy, and the planes 

 bright; that parallel to M and M' is less 

 determined, although sufficiently apparent. 



P on M, or M' 90° 0' 



Pone, ore' 137 48 



MonM' 90 



M on c 132 12 



Acetate of Slronfia. 



The crystals I have obtained of this salt from a solution of the 

 carbonate in acetic acid are very small, with rather imperfect 

 planes, and have not afforded distinct cleavages parallel to any 

 of these. There is, however, an appearance of cleavage parallel 

 to the plane M of the annexed figure. 

 From the general character of the crystals 

 and from measurement, a right oblique- 

 angled prism may be regarded as their pri- 

 mary form. The crystals are very efflores- 

 cent. 



M on T 96° 



/ 



M on d, 

 Mon/ 



107 

 129 



M on e 153 



T on e 122 



d on d' 124 



10' 

 33 

 20 

 12 



58 

 54 



>t 



Nitrate of Strontia. — Anhydrous. 



The primary form is a regular octahedron. The crystals gene- 

 rally resembling those of nitrate of lead, given in the number of 

 the Annals for January last. 



Hydrous. 



A very efflorescent salt, and not affording any distinct cleav- 

 age that I have been enabled to discover. We may assume an 

 oblique rhombic prism as its primary form. The crystals are 

 sometimes considerably lengthened, and 

 present only those planes which are marked 

 as the primary. 



