"k^nnedy?] PHYSICAL PROPERTIES OF THE OIL. 147 
Mexico « _ _ . 874- . 970 
Beaumont * .004- .925 
Wyoming « .912- .945 
California < . 920- . 983 
Saratoga (Hooks No. 1)^. _ . 937 
Sour Lake ' . 945- . 963 
Brazoria County, Tex.'' .965 
Borneo « .965 
PLASH AND BURNING POINT. 
A roughly approximate ratio exists between the specific gravity of 
any petroleum and its flashing- point, and as a general rule a low 
specific gravity accompanies a low flashing point, and while the 
burning point of an oil is usually from 10° to 15° higher than the 
flashing point, this is not always the case. An oil having a high 
flashing point always has a high burning point, but, on the other hand, 
a high burning point may be accompanied by a low flashing point. 
The flashing test of an oil is made for the purpose of determining 
the lowest temperature at which it gives off an inflammable vapor, 
and is the most important test which can be applied to any petroleum, 
since it is to the inflammable vapor evolved at ordinary temperatures 
that most of the accidents are due. This point is quite independent 
of the burning point and depends altogether upon the character and 
amount of the volatile constituents, while the burning point depends 
upon the character and composition of the oil as a whole. 
The presence of the lighter hydrocarbons lowers the flashing point, 
since these volatilize more readily than the heavier hydrocarbons. 
The effect of benzine in varying proportions in lowering the flashing 
point, as determined by Wilson/ is shown in the following table: 
Effect of mixture of benzine on flashing point. 
Flashing 
point. 
Burning 
point. 
\ 
.,. 
°F. 
Oil alone . 
118 
135 
i Mixed with— 
1 per cent benzine 65° B 
112 
129 
3 per cent benzine 65° B 
103 
123 
5 per cent benzine 65° B 
96 
116 
10 tier cent benzine 65° B 
* 
83 
102 
1 per cent benzine 72° B 
m 
133 
5 per cent benzine 72° B 
" 
105 
a Redwood, Petroleum and its Products, 188(>, Vol. I, p. ITS. 
''Jour. Soc. Chem. Industry, Vol. XX, p. 691 et seq, 
''Watts, Oil and gas: Bull. Cal. State Mining Bureau No. lit. p. 204. 
<t Worrell, analyst, Texas Mineral Survey. 
e Jour. Soc. Chem. Industry, Vol. XIX, p. 132. 
/Crewe, Practical Treatise on Petroleum, 1887, p. 359. 
