20 ON THE REDUCTION OF LIMAILLE. 



reasonably be expected to afford results equally 

 satisfactory. 



I would remark, that the silver whicli has been 

 dissolved by the nitric acid may be recovered, by 

 precipitating it with a little chloride of sodium, 

 and afterwards treating the precipitate with zinc 

 and diluted sulphuric acid, a process no doubt 

 well known to every one accustomed to working 

 with precious metals. 



I would refer also to the importance of having at 

 hand large evaporating dishes, or vessels of some 

 kind, to receive the washings during the process, 

 especially if carried on in a hurry, so that the 

 particles of gold, which are liable to escape with the 

 water, may be allowed to settle, and be collected 

 afterwards. I need scarcely observe that separate 

 vessels will be requisite during the process of wash- 

 ing with water. 



It may be thought objectionable, in a sanatory 

 point of view, to employ bichloride of mercury. 

 The decomposition of the materials, through the 

 agency of the fire is, I believe, so complete, that the 

 escaping gases, during the process in the furnace, 

 are rendered as innocuous as need be. 



I have, however, substituted a like quantity of 

 chlorate of potass instead of the bichloride of mer- 

 cury. The only difference in the result was, that the 

 gathering of the gold was not quite so thoroughly 

 effected, although the quality of the product was 

 slightly improved by its adoption. 



