456 Dr. A. Schrauf on Molyldates and Vanadates of Lead. [May 4, 



eosite than in chromate of lead. The streaks of the Ruskberg crystals and 

 of those from Berezowsk are quite identical ; the powder of the Phenixville 

 crystals is light orange, verging into sulphur-yellow. 



The Ruskberg and Phenixville chromo-wulfenites, treated with hydro- 

 chloric acid in the way above described, both leave a deep-blue precipitate 

 with a yellowish-green margin. Fused with bisulphate of potash in a 

 platinum spoon, they both give a saline compound, becoming very faintly 

 yellowish green after cooling. In the beginning of fusion a brownish- 

 purple tint appeared, especially on the Phenixville crystals. This circum- 

 stance, not remarked in eosite or vanadate of lead, confirms the fact ascer- 

 tained by Prof. Rose, of chromium being a prevailing component of the red 

 wulfenites of the Banat, with which, according to my observations, I rank 

 also the yellowesh-red wulfenites from Phenixville. According to Mr. 

 Smith, these last contain vanadium ; however, the specimen before me, 

 when fused with bisulphate of potash, would certainly have manifested the 

 presence of this metal had it been a prevailing constituent, as chromium 

 really is. At all events, the red wulfenites may possibly contain a certain 

 proportion of vanadium, as may be expected with regard to nearly all wulfe- 

 nites in consequence of Prof. Wohler's statements. 



§ 4. Chemical properties of the Vanadates of Lead (Dechenite, Descloizite, 



and Vanadinite)* 



Eosite, as containing vanadic acid, stands next to the just-mentioned 

 vanadates of lead. Dechenite was first found in 1851 by M. Krantz, 

 near Schlettenbach ; and M. Rergemann, neglecting a notable proportion 

 of zinc * contained in this mineral, has stated for it the chemical formula 

 V0 3 PbO. Yanadinite, first found at Kappel (Carinthia), received its spe- 

 cific name by the late Prof. Zippe, and is, according to M. Tschermak, 

 PbOV0 3 . Descloizite was stated by Mr. Damour (1854) to correspond 

 to the formula 2PbO, V0 3 . I have, as early as 1861 f, expressed the 

 opinion that these three species, concordant in a great number of properties, 

 maybe considered as being specifically identical. M. Czudnowicz (I. c), in 

 his paper on vanadinite, has offered several arguments against the vana- 

 dium supposed to enter into the composition of these minerals, so near re- 

 lated to each other that they must be submitted altogether to comparative 

 investigation. The Peruvian descloizite is of so rare occurrence, that I 



* See Czudnowicz in Poggend. Ann. vol. cxx. 



*f* See Schrauf, in Poggend. Ann. vol. cxvi. I must here remark expressly, in order 

 to avoid misunderstandings, that in the course of this paper I have purposely quoted 

 the formulas of preceding authors with the (older) symbols used by them to express 

 vanadic acid. I do not intend to discuss the results of former analyses, because Pro- 

 fessor Roscoe, in the course of his ingenious researches concerning vanadium, has ex- 

 pressly (see Proceedings of Royal Society, vol. xvi. p. 226) said, " It is the author's inten- 

 tion to investigate the composition of the vanadates at a future time." 



