OF CENTRAL CANADA PART I. 39 



over the spirit-lamp or by the blowpipe flame. The spoon is then 

 placed on the blowpipe anvil, and, whilst the smooth or unused end 

 of the agate pestle (or other similar object, a glass button cemented 

 to a cork, for example) is pressed firmly on the surface of the bone- 

 ash, the handle of the spoon is moved three or four times from side 

 to side. The surface of the cupel thus formed is then exposed for a 

 few moments to the point of the flame, so as to render the bone-ash 

 thoroughly dry ; and if its smooth condition be in any way affected 

 by this treatment, the pressure with the pestle is repeated. Another 

 equally good, if not better support consists of a cylindrical piece of 

 pumice or well-baked clay with a small saucer-shaped depression for 

 the bone-ash at its transverse end. The substance to be cupelled 

 must be in the metallic state ; if not in this condition, therefore, it 

 must first be subjected to the reducing process described above. In 

 actual assaying or quantitative operations, this process is modified in 

 various ways, but in the present work, in which merely a brief out- 

 line of the use of the blowpipe is attempted, it would be out of place 

 to enter into these details. The piece of test-metal, which may weigh 

 about a couple of grains (or from 100 to 200 milligrammes) is wrapped 

 in a piece of pure lead-foil of three or four times its weight, and the 

 whole is exposed on the surface of the cupel to the extreme point of 

 a clear oxidating flame. If the substance consist of argentiferous 

 lead, as obtained from galena, <fec., the addition of the lead-foil is of 

 course unnecessary.* Six or seven grains (or from 400 to 500 milli- 

 grammes) may be taken for the experiment : a beginner, at least, will 

 not find it advisable to operate on a larger quantity at one time. As 



* " In reducing galena, with a view to test the reduced lead for silver by cupellation, the reduc- 

 tion may be conveniently performed as follows : a small portion of the galena, crushed to powder, 

 is mixed with about twice its volume of carb. soda to which a little borax has been added. 

 This is made into a stiff paste by the moistened knife -blade or blowpipe spatula, and a short 

 piece of thin iron wire is stuck through it. The whole is then placed in a tolerably deep cavity 

 scooped in a good piece of charcoal, and is exposed for a couple of minutes to the action of a 

 reducing flame. By a little management, the minute globules of lead, which first result, can 

 easily be made to run into a single globule. The iron assists in taking up sulphur from the 

 galena. When sufficiently cool the fused mass is removed by a sharp knife-point, and flattened 

 (under a strip of paper) on the anvil. The disc of reduced lead, thus separated from the slag, 

 is then ready for cupellation." CHAPMAN'S BLOWPIPE PRACTICE. 



In the case of ordinary ores or matters suspected to contain gold or silver, tha roasted test- 

 substance must be mixed with about an equal quantity pf pure litharge or granulated lead and 

 a proper amount of flux, aud subjected to fusion in a charcoal cavity. The lead or reduced 

 litharge takes up any gold oa silver that may be in the ore, and this is set free by subsequent 

 cupellation as described above. 



