This last is poured into a flat-bottom capsule,
and allowed to cool slowly. The temperature may with advantage be
carried below freezing-point. The cooled cake is pressed between folds
of linen, and the paraffin scale detached and weighed.
The results may be reported thus:--
Naphtha, sp. g. ----
Light oil, sp. g. ----
Heavy oil, sp. g. ----
Paraffin scale ----
Coke, &c. ----
The results are calculated in per cents. on the oil taken. Some workers
take their fractions at each rise of 50° C. The composition of average
shale, as given by Mills, is as follows:--Specific gravity, 1.877;
moisture, 2.54.
Gas }
Volatile matter, water, ammonia } 23.53
Oil }
Fixed carbon 12.69
Ash 63.74
_____
99.96
The ash is made up of silica, 55.6; ferric oxide, 12.2; alumina, 22.14;
lime, 1.5; sulphur, 0.9; soluble salts (containing 0.92 per cent.
sulphuric oxide), 8.3.
Total sulphur in shale 1.8 per cent.
" " in ash 1.3 "
For further information on these assays, and for the assay of
petroleums, bitumens, &c., the student is referred to Allen's
"Commercial Organic Analysis," Vol.
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