OF CENTRAL CANADA PART I. 



35 



PHOSPHOR-SALT. 



The glasses produced by the fusion of constituent bodies with this reagent 

 are for the greater part identical with those obtained by the use of borax, 

 although somewhat less deeply coloured as a general rule. The principal ex- 

 ceptions are the glasses formed in a reducing flame with compounds of Molyb- 

 denum, Tungstenum, and Titanium, respectively. The molybdenum glass 

 presents, when cold, a fine green colour, and the tungstenum glass becomes 

 greenish-blue. If the latter contain iron, the colour of the glass is changed to 

 blood-red or brownish red. Titanium in the presence of iron gives a similar 

 reaction ; but when free from iron, the glass is yellow whilst hot, and violet- 

 coloured when cold. Phosphor salt is an important reagent for the detection 

 of silica in silicates, as the silica remains for the greater part undissolved in 

 the glass, in the form of a translucent flocculent mass technically known as a 

 "silica skeleton," the associated constituents being gradually taken up by the 

 flux. A small amount of silica is also generally dissolved, but this is precipi- 

 tated as the bead cools, rendering it semi-transparent or opaline. Phosphor- 

 salt is likewise employed for the detection of chlorine, &c. (See Experiment 

 3, page 43. 



CARBONATE OF SODA. 



This reagent is principally used to promote the reduction of oxidized and 

 other bodies to the metallic state, as explained under the description of that 

 process. (Operation 6, below. ) It is also of frequent employment as a test for 

 sulphur in sulphides and oxidized bodies. (See under Reactions.) It is rarely 

 used, on the other hand, for the formation of glasses on platinum wire, except 

 as a test for the presence of manganese ; although when employed, in this man- 

 ner, it serves to distinguish salts of the alkalies, and those of strontia and 

 baryta from all other salts : the alkalies, with baryta and strontia, dissolv- 

 ing completely and rapidly in the bead, whereas lime, magnesia, alumina, and 



