lb'b' Mr Johnston on the Vanadiate of Lead. 



with which we are familiar in nature, may be produced by slow 

 cooling or other processes according to the above theory, may 

 we not look to it also, to account for the crystallization of the 

 gem ? 



This conjecture rests upon the truth or fallacy of Sir James 

 HalPs theory, or on a modification of it, and when this theory 

 is considered as the result of long and patient experiment, and 

 the high reputation of its author is taken into account, it will 

 require something more than limited observation, or ordinary 

 ability, to answer its objections ; my part, however, is merely 

 the suggestion of a traveller, and I therefore conclude my pa- 

 per by expressing a hope, that this important mineral may meet 

 with more able investigation. 



Art. XIX — On the Discovery of Vanadium in Scotland, and 

 on the Vanadiate of Lead, a new Mineral species. By James 

 F. W. Johxston, A. M. Sec. &c- Communicated by the 

 Author. 

 It is a remarkable circumstance, and illustrative at once of 

 the wide diffusion of chemical knowledge, and of the progress 

 of scientific chemistry, that the new metal Vanadium has been 

 discovered in three different countries nearly at the same time, 

 and without any communication between the several indivi- 

 duals by whom it has been observed and detected. First in 

 order of time, Professor del Rio, of the School of Mines of 

 Mexico, detected a new- metallic substance in the brown lead- 

 ore of Zimapan, to which, probably from its forming red salts, 

 he gave the name of Erythronium. His results were not pub- 

 lished, however, M. Collet Descotils, to whom specimens 

 were ti'ansmitted, having pronounced it to be an impure chro- 

 mium. Meantime Proftssor Sefstrom, of the School of Mines 

 at Fahlun in Sweden, detected in an ore of iron a simple me- 

 tallic body, which he named Vanadium, and of which he an- 

 nounced some of the properties about the end of the past year. 

 The metal of del Rio, it now appears, is the same with that 

 of Sefstrom. 



In the course of last winter my attention was directed to a 

 mineral from Wauloeklicad, which I obtained from Mr Rose 



