168 
POPULAR SCIENCE REYIEW. 
can oil, and these gave me explosions in an experimental lamp. 
The American oils could be rendered non-explosive j ust as easily 
as Young’s, but it is against the interest of f the trade ’ to do 
this. It is true there is an Act of Parliament, which came into 
operation in October, 1862, forbidding the warehousing of much 
more than one barrel of American oil, unless proof is forth- 
coming that it gives off no inflammable vapour, below 100 
degrees; but merchants, brokers, and dealers in the oil con- 
sider these words to mean that the oil itself shall not ignite 
under 100 degrees, when a lighted match is dipped into it, 
which is really a very different thing. For oil that will not 
take fire under 100 degrees will readily give off inflammable 
vapour at 80 degrees or 90 degrees, and hence always give rise 
to an explosive mixture of vapour and air in the reservoir of 
the lamp in which it is burnt. Until the letter of the Act is 
enforced, therefore, there will always be danger in burning 
paraffin oil in the lamps commonly used. 
Fortunately the chances against the explosive mixture of 
vapour and air catching light in a paraffin lamp are very great. 
There is, however, one little hole in the upper part of every oil 
lamp, an aperture necessary to the steady burning of the lamp, 
and it is this which, doubtless, forms the touch-hole, by which 
fire has at times been conveyed from the flame of the lamp 
to the mixed vapour and air in the reservoir. But in paraffin 
lamps there is always a strong current of air passing over the 
external part of this orifice, in its passage upwards to support 
the combustion of the flame, and hence the successive portions 
of the inflammable mixture which escape through the aperture 
are at once so largely diluted with air as to be harmless. Should 
this current of air be arrested, as when a lamp is extinguished 
by placing a cap over the top of the glass chimney, or when the 
flame is put out by blowing down the chimney, or when the 
wick is being turned down and the chimney simultaneously 
removed by a cloth placed round the lower part of the chimney 
to protect the hands, or by other occasional circumstances, then 
the liability of the explosive mixture to ignition is greatly 
increased. Paraffin oil is an excellent and cheap illuminating 
agent, and if traders would only take a little more pains in 
refining it, so as to remove as much as possible of the un- 
pleasant odour it possesses, and render it as safe as the old 
vegetable oils, which could be done with perfect ease, its present 
large sale would doubtless be immensely increased. 
