British Mineralogy. 339 



to the principal gold-localities of Wales for the express purpose 

 of obtaining information connected with the mineralogical and 

 geological relations of the appearance of this metal in the rocks 

 of the Principality*. m 



Gold from the Clog ait Quartz Lode No. 2. 



This specimen was taken from the stamps, and was the result 

 of quartz mined from the backs of the lode, almost on the sur- 

 face, and was in the form of minute flattened grains, nearly free 

 from any mineral admixture, and of a fine yellow colour. 



The specific gravity, taken with 34*08 grains free from any 

 visible impurity, was found to be 17*26 at the temperature of 

 60° P. 



The chemical analysis was conducted as follows : — A weighed 

 amount of the gold was dissolved as far as possible in nitrohy- 

 drochloric acid and evaporated nearly to dryness in a water-bath, 

 then redissolved in water slightly acidulated with hydrochloric 

 acid, and filtered from the chloride of silver and insoluble quartz, 

 which were determined conjointly and afterwards treated with 

 ammonia, which by dissolving out the chloride of silver, left the 

 quartz behind for estimation. 



From the filtrate, after being heated to nearly boiling, the 

 gold in its metallic state, along with any copper present (in the 

 form of oxalate), was precipitated by the addition of a strong so- 

 lution of oxalic acid. The metallic gold was then collected on 

 a filter and washed, first with water and then with weak solu- 

 tion of ammonia, in order to dissolve out any oxalate of copper 

 which might be present; these last washings, with ammonia were 

 collected separately and tested for copper. 



The first filtrate and washings, which would contain any iron 

 present in the gold, were now evaporated to dryness and the iron 

 subsequently determined as usual. 



34*08 grs. of gold afforded 4*19 grs. chloride of silver and 

 0*1 1 gr. of insoluble quartz along with 30*69 grs. of precipitated 

 gold. These results tabulated will give the composition as fol- 

 lows : — 



* The author would here express his obligations to Mr. Arthur Dean, 

 the Director of the Vigra and Clogau gold mines, for the facilities afforded 

 him in his examination, and for the valuable information which that gentle- 

 man's long practical experience in the district enabled him to communicate. 

 The development of gold-mining in Wales may be entirely ascribed to the 

 perseverance and exertions of Mr. Dean ; and the author would also add 

 his belief that, had the large amount of capital already invested in Welsh 

 gold-mining companies been but legitimately and judiciously expended upon 

 the mines themselves, several more of these undertakings would still be in 

 existence. 



