47 
USES. 
Though one of the most important uses of graphite is for 
the manufacture of refractory articles, there is very little used 
in Canada for this purpose. In the manufacturing of crucibles, 
retorts, etc., flake graphite of a number of sizes is used. It 
should be of slow combustion and good thermal conductivity; 
hut the amount, and chemical composition of the contained 
impurities are the main factors in determining the suitability 
°f any graphite to this purpose. The presence of fluxing im 
purities would tend to shorten the life of the finished article, if 
not render it unfit for use. 
Stove polishes consist essentially of finely ground graphite, 
usually 160 mesh, with which is mixed clay or some other material 
to act as a bond. Both the flake and amorphous varieties are 
used. Professor B. L. Miller says; 1 “If flake graphite is used a 
higher lustre is obtained which has a decidedly steel grey colour. 
This is owing to the flattening out of the flakes on the metal 
surface when rubbed by the brush, and to the fact that light 
reflected from the surface of the flakes produces a higher lustre 
than when the amorphous graphite is used. Not infrequently 
both amorphous and crystalline flake graphite are mixed to 
gether to produce the desired results. With the amorphous 
graphite alone it is difficult to obtain a lustrous polish, while 
the crystalline flakes alone produce too light a colour, but the 
eombination of the two varieties will yield a black polished sur- 
face with expenditure of little labour- The polish obtained 
^rith the flake graphite alone, or with the mixture of the two, 
lasts longer than the polish obtained with amorphous graphite 
alone.” For polish making purity is not of importance, from 
per cent to 80 per cent of carbon being usual. 
The finishing step of the manufacture of gunpowder con- 
sists of polishing the grains with graphite. The powder is 
Placed in a tumbling barrel with very fine flake graphite and 
thoroughly mixed and shaken for some time. The thin film of 
1 “ Graphite Deposits of Pennsylvania,” Topographic and Geologic Survey of } Permsyl- 
^ nSa * Report No. 6, 1912.