288 T.O'C. Sloane—Anaiysis of Bituminous Coal. 
it exacts more attention and trouble. The salt fusion, in two 
comparative determinations that I made, gave higher results on 
the same coal, 
Salt Fusion. Deflagration. 
2 US sae cane 1°70 p. ¢. 1°37 p. ©. 
S| eS ae 1°92 1°69 
The specific gravity cannot be satisfactorily determined with- 
out the specific gravity bottle. y weighing lumps in air 
and in water all sorts of results will be obtained. I break up 
a sample in an iron mortar and pass it through a No. 4 or 
6 sieve. I then shake it up in a finer, No. 15 or 20, sieve, so 
as to free it from the dust and fine particles. This seems a 
bad practice yet cannot well be avoided. The finely divided 
coal, if left in with the rest, will float on the surface of the 
water used in determining its specific gravity, and no amount 
of boiling will make it sink. 
e coal thus prepared I place in a small beaker with some 
distilled water, and boil it. I then put the coal and water 
into the specific gravity flask, fill up with recently boiled 
distilled water, and cool it to about the temperature of 
the room. The last cooling is done in a beaker of water 
which is stirred once or twice, during the cooling, to make the 
water of uniform temperature. When the bottle and contents 
have attained this temperature, the bottle is carefully filled, 
the stopper put in, and the whole dried and weighed. The 
coal is then thrown out, the bottle filled with recently boiled 
distilled water, brought to the same temperature as before, and 
weighed. This careful reduction to one temperature is very 
important; by paying attention to it very close duplicates can 
be obtained. 
The specific gravity of coal varies with the percentage of 
ash ; yet the correspondence is not so perfect as to make the 
determination of the specific gravity a substitute for that of 
the latter constituent. As the degree of correspondence is a 
"some interest, I give below a number of parallel 
determinations of ash and specific gravity. 
Specific gra Ash. SS) ¢ gravity. 
fi Sere 4°02 p. POCT. ce. 7°23 p. ¢ 
1300 22... 15406 108 cs 
1°286 222°. 24°14 Pose [sles 10°38 
11206 2. see 4°68 Sy Gee ee 13°98 
1906.25, 65,818 en eee es 16°22 
190420354. 5°78 
Tracing Cloth instead of Glazed Paper. 
For the purposes of sampling and pulverizing minerals, 
coals, fertilizers, &c., for analysis, glazed paper is generally 
