185 



, 



176. CERIUM NITRATE. Ce2NO s . 



a. Crystallized. 



177. OXALATE. Ce C 3 O 4 , 3H 2 0. (Cerii Oxalas, D.P.) 



a. Powder. 



LANTHANIUM. La. 



178. SULPHATE. La S 4 , 3H 8 0. 



t a. Crystalline powder. 



DIDYMIUM. Di. 



179. SULPHATE. Di S 4 , 2H 2 0. 



t a. Crystalline Powder. 



MAGNESIUM. Mg. 



180. METALLIC. 



a. In the form of wire and ribbon. 



181. CARBONATE. (Mg C 3 ) 3 Mg 0, 5H 2 0. (B.P.) 



a. In powder. (Light Carbonate of Magnesia.') 



b. Ditto. (Heavy Carbonate of Magnesia.) 



c. lu cubes. 



d. In crystals, having the composition Mg C 3 , 3H 2 0. 

 Note. Specimen d consists of crystals deposited from a solution of the 



acid carbonate. For fig., see Per. Mat. Med., vol. L, p. 654. The com- 

 position of magnesic carbonate in powder is not constant. 



* e. Native, a fine specimen, presented by Messrs. Huskis- 



son & Co. 



Note. For analysis, etc., see Dana, Mineralogy, p. 685. For specimen* 

 of Dolomite (native calcic carbonate of magnesium), see the central case 

 containing minerals (Case No. 8). 



182. CHLORIDE. MgCl 2 . 



a. Anhydrous, as used for preparing magnesium. 



b. Crystallized, impure. 



c. Ditto, purified. 



d. Ditto, fused. 



183. LACTATE. Mg (C 3 H 5 3 ) 2 , 2H 3 0. 



a. In powder. 



184. OXIDE. MgO. 



a. In powder. (Light Magnesia, B.P., Light Calcined 



Magnesia.) 



b. Ditto. (Magnesia, B.P., Heavy Calcined Magnesia.) 



185. SILICATE. 



a. Native, prepared for use in trade. 



b. Ditto, in powder. 



Note. For native specimen of thi* substance, and otJier minerals contain- 

 imj magnesic silicate, see the central case containing minerals (Case No. 9). 



