28 MM. Gcuthcr and Forsberg on Artificial Tungstates. 



bases crystallized exactly in the forms in which they occur in 

 Scheelite ; and Geuther and Forsberg* have obtained a series of 

 tungstates by the same method. They found that the addition 

 of common salt is necessary in order to obtain large crystals. 

 They have prepared the tungstates of baryta, magnesia, zinc, and 

 cadmium, and find that these bodies are isomorphous with the 

 lime and lead salts. They also prepared the tungstates of iron 

 and manganese, as well as some of their double salts. These 

 latter bodies crystallize in rhombic forms, like the native tung- 

 sten. By using different quantities of the chlorides of manga- 

 nese and iron, the various natural tungstens may be obtained in 

 beautiful large crystals. 



The preparation was effected by placing a mixture of the salts 

 in a covered porcelain crucible, which stood in a Hessian crucible 

 half-filled with magnesia. This was heated in a wind-furnace, 

 and allowed to cool slowly ; when the fused mass was extracted 

 with water, the crystals were left undissolved. 



Of the various double tungstates of iron and manganese pre- 

 pared, the compound 7(MnO WoO 3 ) +FeO WoO 3 was obtained 

 in small brown crystals. It probably corresponds to a Wolfram 

 from Schlackenwalde analysed by Rammelsberg. The compound 

 2(MnO, WoO 3 ) +3(FeO WoO 3 ) was obtained in crystals 5 to 6 

 millims. in length. It corresponds to no natural compound. 

 The compound MnO Wo0 3 + 4(FeO WoO 3 ) corresponds to a 

 Wolframite from Ehrenfriedensdorf ; and another, with the com- 

 position MnO WoO 3 + 7FeO WoO 3 , to a Wolfram from Neudorf, 

 analysed by Bammelsberg. A compound was obtained in lamel- 

 lar crystals which had the formula MnO WoO 3 + 3 FeO WoO 3 ; 

 it corresponds to the Wolfram of Limoges, and to a specimen, 

 from Cumberland analysed by Berzelius. Attempts were made, 

 but without success, tp obtain crystallized tungstate of chrome 

 and tungstate of silver. 



In an investigation of the higher degrees of oxidation of 

 bismuth, Schraderf has arrived at the following results : — 



In the cold, hypochlorite of potash exercises no oxidizing 

 action on oxide of bismuth. 



If hydrated oxide of bismuth be boiled with an alkaline hypo- 

 chlorite, substances richer or poorer in oxygen are obtained, 

 according as potash is present in greater or less excess. 



The bodies obtained by treatment with dilute alkalies are 

 soluble in concentrated nitric acid; treated with dilute acid, 

 brown anhydrous bodies are formed which correspond to the 

 formula BiO 4 . 



When boiled with concentrated alkali of the specific gravity 



* Liebig's Annalen, December 1861. f Ibid. February 1862. 



