ON THE IGNITING-POINT OF PETROLEUM. 
323 
“ gives off an inflammable vapour at a temperature of less than one hundred 
degrees of Fahrenheit’s thermometer,” the law has not yet had the effect an¬ 
ticipated, namely, the exclusion from retail trade of that quality of petroleum 
which is so badly refined as to have dangerous, because unsuspected, properties. 
TABLE OF GRAVITIES AND IGNITING-POINTS OF COMMERCIAL PETROLEUM. 
Igniting-point of vapour in degrees Fahrenheit. 
Name, Brand, or Distinc¬ 
tive Mark. 
Specific Gravity 
In open bowl. 
In bottle. 
1 T T Cirl-'V/X — 'XW V 1 • 
Without agita¬ 
tion. 
With violent 
agitation. 
“Woodville” , . . 
796 
80 
76 
70 
A. 
797 
98 
83 
78 
^‘Standard” .... 
798 
96 
95 
85 
“ Caynga ” .... 
798 
81 
80 
70 
B. 
799 
101 
87 
71 
“ Denmark ” . . . . 
799 
94 
86 
85 
“ Hutchinson ”... 
800 
90 
86 
84 
“Lucifer” .... 
801 
91 
81 
78 
“ American Paraffin Oil ” 
801 
92 
80 
68 
“ Commercial ”... 
803 
104 
81 
79 
“American Petroleum,” 
No. 1. 
804 
134 
134 
111* 
„ „ No. 2. 
805 
93 
90 
74 
,, ,, No. 3. 
806 
83 
76 
66 
“CommonParaffin Oil” 
806 
105 
90 
83 
“Brilliant” .... 
808 
83 
74 
72 
“ Young’s Paraffin Oil ” 
(not a Petroleum) . 
819 
116 
97 
91 
And now, with regard to a method of taking the igniting-point of petroleum- 
vapour, which shall be reliable and constant in the results of its application. 
As petroleum is not a definite chemical compound, but a varying mixture of 
several hydrocarbons; as, in short, it has no constant chemical or physical pro¬ 
perty of which advantage might be taken in devising a ready method of taking 
igniting-points, it follows that the method selected must be more or less arbi¬ 
trary, empirical, conventional. It is true, that their volatility is a constant 
physical property, and MM. Salleron and Urbain in France, have, it is said, 
contrived an apparatus for taking the tension of the vapour of mineral oils, 
which is obviously proportional to their volatility, adopting 64 millimetres of 
water at, apparently, 35° C. as the limit of safety ; but only an abstract of their 
paper was published, in the ‘ Comptes Rendus’ of January 2, 1866 ; their full 
paper does not seem to have been printed, so that I am unable to judge of the 
merits of the method. It has not the recommendation of being a direct process. 
The only feasible plan would seem to be, select a direct method, simple in prin- 
* This is an interesting specimen. Its light coloui’, hoth when pnrchased and after being 
exposed to the light for some time, and its specific gravity, indicate that it really is a petro¬ 
leum, and not a paraffin oil. It was pnrchased a retail shop in Drury Lane, London, as “our 
best, A\d. per pint.” Another quality, sold at the same shop at 4t^. per pint, had a higher 
specific gravity, 806, hut much lower igniting-point. Tried in the manner recommended at 
the end of the paper, the “best” gave ofi' inflammable vapour at 114°, the other at-86°. The 
properties of this sample prove, or at least indicate (for I could not get at the history of the 
bulk) that it is easy to supply the public with a perfectly safe petroleum at a reasonable price, 
a petroleum so low in specific gravity as to readily ascend a wick, and so high in igniting- 
point as not to be dangerous under ordinary circumstances. 
