CHAPTER III. 



TESTING MINERALS BY THE BLOWPIPE. 



Apparatus required. How to use the blowpipe. Nature of the 

 flames. Methods of testing in an open tube and a tube closed 

 at one end. On charcoal with carbonate of soda. With borax 

 and microcosmic salt on platinum wire. Tables of reactions with 

 borax and microcosmic salt. Testing with nitrate of cobalt. 

 General table (for the qualitative analysis of metallic sub- 

 stances). Confirmatory tests. To detect certain common sub- 

 stances associated with metals. Temporary blowpipe. 



APPAEATUS required consists of the following : Blowpipe. 

 Candle or lamp (fed with oil or melted tallow). Forceps 

 with platinum points. Charcoal. Steel forceps. Platinum 

 wire and foil. Magnet or magnetic needle or magnetic 

 knife blade. Knife. Mortar (agate is the best material) 

 and pestle. Borax, microcosmic salt, carbonate of soda in 

 small boxes. In addition to the above, a small bottle of 

 hydrochloric acid, and also some nitrate of cobalt solution, 

 will be most useful. A few small open glass tubes, and 

 glass tubes closed at one end. Many other articles might 

 be of great use, such as a small aluminium plate, some 

 nitric acid, sulphuric acid, zinc for confirmatory tests, and 

 also hyposulphite of soda ; at the same time, they are not 

 absolutely necessary. 



In testing the quality of a mineral by the blowpipe, a 

 small but well-chosen fragment about the size of a mustard- 

 seed is sufficient. 



In using the blowpipe, the principal thing to learn is to 

 blow and breathe at the same time without removing the 

 mouth from the instrument. This is effected by filling the 

 mouth with air and gently blowing, and at the same time 

 by breathing through the nostrils. 



A lamp with a large wick, and fed with olive oil or melted 

 tallow, affords a good flame, and so does an ordinary candle 

 with a broad wick. 



The blowpipe flame consists of two parts, the blue one 



