OF CENTRAL CANADA PART I. 43 



Experiment 3. Dissolve a few particles of black oxide of copper in 

 phosphor-salt on platinum wire, so as to form a strongly-coloured glass. 

 (Or simply melt some of the salt in a loop of thin copper-wire.) To 

 this, add the test-substance, in powder, and expose the whole to the point 

 of the blue cone. 



This experiment serves directly for the detection of chlorides. 



a. The fused bead is surrounded by a bright azure-blue flame. 

 Note : The coloration is produced by the volatilization of chloride 

 of copper. It ceases therefore, after a time, but may be renewed by 

 more of the test-substance being fused into the bead. The rare 

 Bromides and Iodides can also be distinguished by this experiment. 

 The former produce a blue flame with green streaks and edges, the 

 latter a bright emerald-green coloration. 



Experiment 4- Moisten the substance, in powder, with a drop of sul- 

 phuric acid, and expose on platinum wire to the point of the blue flame. 



This experiment serves for the detection of Phosphates and Borates. 

 as these bodies impart, when thus treated, a clearly marked green 

 colour to the flame-border. The borates communicate also a green 

 colour after previous treatment with a few drops of sulphuric acid 

 to the flame of alcohol. The phosphates and borates of natural occur- 

 rence are without metallic aspect. All dissolve readily in borax and 

 phosphor-salt before the blowpipe. Many communicate a green 

 colour to the point of the flame when strongly ignited, per se. It 

 must not be forgotten, however, that certain other bodies, oxide of 

 copper, baryta, &c., also colour the flame green. Phosphates may 

 also be detected as follows : Melt some of the substance in fine 

 powder with about 3 vols. of carb. soda, on platinum wire, or in a 

 small platinum spoon. Treat the fused mass with a few drops of 

 boiling water (in a test-tube, or, better, in a small porcelain or plati- 

 num capsule, over the spirit lamp), decant the clear solution ftpm 

 the insoluble residuum, add some nitric acid, and place in the solution 

 a fragment of ammonium molybdate. This forms a canary-yellow 

 precipitate with solutions of phosphates. In most cases the mineral 

 may be treated directly (in powder) with nitric acid, and the diluted 

 solution tested with ammonium molybdate. The yellow precipitate 

 rapidly forms on the solution being warmed. It is readily soluble in 

 ammonia. 



