380 
PHAiniACEUTICAL MEETING. 
and probably did mean, that the petroleum itself should not ignite under 100 
degrees when heated by a flame or a water-bath in an open saucer or small 
bowl,—a most fallacious test, first, because the time employed in the operation, 
the amount of stirring practised, the form of the vessel, its arrangement over 
the source of heat, the quantity of liquid used, and the distance of the test- 
flame from the surface of the petroleum, all influenced the result to the extent 
of causing two observations to vary from 4 to 40 degrees from each other; and, 
second, because the experiment thus performed invariably gave the iguiting- 
point many degrees higlier than the temperature at which inflammable vapour 
was evolved,—than the temperature, therefore, at which the oil was dangerous. 
Shippers, merchants, brokers, adopted this fallacious mode of testing; oil 
changed ownership under a warrant that it would not ignite under 100 degrees, 
not, however, without occasional litigation caused by the uncertainty of the 
test, and hence the market was and is supplied with oil which emits inflammable 
vapour in most cases below 90 and often below 80 degrees. 
The remedy is plain. Let those who sell and those who buy discountenance 
the sale and use of those qualities of mineral oil which generate inflammable 
vapour at temperatures below 100 (better 110) degrees, when examined in a 
test-tube in the manner already indicated. Such tubes may be purchased for a 
few pence of any chemical apparatus maker, naked thermometers can be obtained 
at the same places, or these articles, together with an instrument for ascertain¬ 
ing the power of the oil to ascend a wick, a spirit lamp, test-flame jet, directions 
for use, etc., all enclosed in a neat pocket case under the name of the Petroleo- 
meter^ are now kept in stock by IMr. Casella, Hatton Garden, London. Oils which 
stand this test may be considered safe, and such oils can be supplied by refiners 
as easily as unsafe ones,—it is only a matter of carrying the reflning operation a 
little further. Indeed, safe oils are even now occasionally met with. At a shop 
in Drur}’’ Lane I purchased petroleum at 4(7. and at 4^(7. per pint; the former 
yielded inflammable vapour at 86 degrees, and gave me an explosion the first hour 
it was burnt in a lamp; the latter only emitted vapour at 114 degrees, and gave 
no explosive mixture in a lamp, even after seven hours’ burning. The use of safe 
oils will be the chief means of avoiding explosions. But the lamps themselves 
are not altogether faultless. The air-hole which allows of air entering the lamp 
and taking the place of escaping oil is usually within about half an inch of the 
flame, it might very well be placed at some other part of the lamp; for it is this 
aperture which forms the touch-hole by which fire is conveyed from the flame 
to the explosive mixture within. Fortunately there is always a strong draught 
of air in the opposite direction, so that the chances are perhaps five hundred 
against, to one in favour of an accident, even though an explosive mixture be 
constantly in the reservoir. Were this not so, explosions with the petroleum now 
in commerce would be the rule rather than exception. 'Blowing down the 
chimney of a lamp neutralizes this current, and doubless increases the chances 
of the flame reaching what I have already termed the touch-hole. Then this 
channel of communication might be packed with wires after the principle of the 
oxyhydrogen safety-jet. Again, the portion of the brasswork facing the interior 
of the lamp should be covered with bone, glass, or some other material, having 
bad cojiducting powers for heat, so that the gateway, as I have before called it, 
through which all the oil has to pass in ascending from the reservoir to the 
flame shall be cool instead of hot. B}'" these means, and especially by demand¬ 
ing that all mineral oils shall comply with the letter instead of what is said to 
be the spirit of the Petroleum Act of 1862, explosions in lamps will seldom or 
never be heard of. 
A few words in conclusion. I have pointed out the cause and tlie remedy; with 
whom will begin the adoption of the means of prevention of these explosions?- 
It is useless to say the refiner ought to do this; the refiner at New York and 
