181 



SILVER NITRATE. 



t /' Fused, in sticks. 



Note. The crystals much resemble those of potassic chlorate in 

 appearance, bat are more transparent and heavier. 



134. OXIDE. Ag 2 0. (Argentic Oxide, Monoxide of Silver.) 



f a. Brown powder. 



DYAD METALS. 

 BARIUM. Ba. 



135. CARBONATE. Ba C 3 . 



a-. Native. (Witherite.) 



b. In powder, impure, precipitated by soda. 



c. Ditto, purified, precipitated by ammonia. 



136. CHLORATE. Ba2C10 3 ,H 2 O. 



a. Crystallized. 



137. CHLORIDE. BaCl 2 , 2H 2 0. 



a. Crystallized, impure. 



b. Ditto, purified. 



138. FERRATE. BaFeO 4 . 



a. In powder of a purplish red colour. 

 Note. This specimen was prepared by Professor Redwood. 



139. NITRATE. Ba 2N O 3 , 5H 3 0. (Nitrate of Baryta.) 



a. Crystallized, impure. 



b. Ditto, purified. 



140. OXIDE. Ba 0. (Monoxide of Barium.) 



a. Anhydrous, in powder. 



b. Hydrated in crystals, BaH 2 2 . (Hydrate of Baryta.) 



141. PEROXIDE. Ba 2 . (Dioxide of Barium.) 



a. In powder. , 



142. SULPHATE. Ba S 4 . 



a. Native. (Heavy Spar, Barytes.) 



b. Precipitated. (Blanc Fixe.) 



Note. Specimen 6 represents the form in which sulphate of barium i 

 used as a substitute for white lead in paint. 



STRONTIUM. Sr. 



143. CARBONATE. SrCO 8 . 



a. Native, in crystallized masses. (Strontianite.) 



b. In powder, precipitated by ammonia. 



144. CHLORIDE. Sr C1 2 . (Muriate of Strontia.) 



a. Crystallized. 



145. NITRATE. Sr2NO s ,5H 2 0. 



a. Crystallized. 



b. Exsiccated, as used by pyrotechnists. 



