346 CONTRIBUTIONS TO BLOWPIPE ANALYSIS. 



9. DETECTION OF MINUTE TRACES OF COPPER IN 

 IRON PYRITES AND OTHER BODIES.* 



Although an exceedingly small per-centage of copper may be de- 

 tected in blowpipe experiments, by'the reducing process, as well as by 

 the azure-blue coloration of the flame when the test-matter is moist- 

 ened with chlorhydric acid, these methods fail in certain extreme 

 cases to give satisfactory results. It often happens that veins of Iron 

 Pyrites lead at greater depths to Copper Pyrites. In this case, accord- 

 ing to the experience of the writer, the Iron Pyrites will almost in- 

 variably hold minute traces of copper. Hence the desirability, on ex- 

 ploring expeditions, more especially, of some ready test, by which, 

 without the necessity of employing acids or other bulky and difficultly 

 portable reagents, these traces of copper may be detected. f The fol- 

 lowing simple method will be found to answer the purpose : — The test- 

 substance, in powder, must first be roasted on charcoal, or, better, on 

 a fragment of porcelain, J in order to drive off the sulphur. A small 

 portion of the roasted ore is then to be fused on platinum wire with 

 phosphor-salt ; and some bisulphate of potash is to be added to the 

 glass (without this being removed from the wire) in two or three suc- 

 cessive portions, or until the glass becomes more or less saturated. 

 This effected, the bead is to be shaken off the platinum loop into a 

 small capsule, and treated with boiling water, by which either the 

 whole or the greater part will be dissolved ; and the solution is finally 



* This method has not been hitherto published ; but it is inserted here, as it 

 has been shown to various persons interested in blowpipe experiments. The 

 same remark applies to No, 1 1. 



t In Blowpipe Practice — as far, at least, as this is possible— the operator 

 should make it an essential aim to render himself independent of the use of 

 mineral acids and other liquid and inconvenient reagents of a similar character. 

 If these reagents cannot be dispensed with altogether, their use, by improved 

 processes, may be greatly limited. 



$ In the roasting of metallic sulphides, &c., the writer has employed, for some 

 years, small fragments of Berlin or Meissen porcelain, such as result from the 

 breakage of crucibles and other vessels of that material. The test-substance is 

 crushed to powder, moistened slightly, and spread over the surface of the porce- 

 lain ; and when the operation is finished, the powder is easily scraped off by the 

 point of a knife-blade or small steel-spatula. In roasting operations, rarely 

 more than a dull red heat is required ; but these porcelain fragments may be 

 rendered white-hot, if such be necessary, without risk of fracture. Canadian 

 Journal, September, 1 860. 



