336 EXPLOSIBILITY OF COAL OILS. 



a burning lamp containing a little kerosene oil of the ordinary temper- 

 ature, without producing any perceptible explosive effect. In this 

 state it was also filled safely. To test the effect of increasing the 

 heat of the coal oil higher than 80°, the lamp, whilst still burning, 

 was placed in a basin of water, the temperature of which was gradu- 

 ally raised to the boiling point. During the progressive increase of 

 temperature burning matches were continally inserted into the orifice 

 of the lamp without perceptible effect in kindling vapor, until the 

 heat became increased to nearly the temperature at which the oil had 

 been found susceptible of being kindled in an open cup. The only 

 mode of producing a slight explosive puff on inserting a burning match 

 Avas by violently shaking the lamp to increase the evaporation and 

 mix the gaseous vapor more thoroughly with the atmospheric air. 

 But Avhen the temperature of the coal oil became further increased 

 to about 160°, the rising gaseous vapor entirely filled the chamber 

 of the lamp and expelled the atmospheric air so completely as to cause 

 lighted matches to be extinguished within the chamber, whilst the 

 ascending gas continued to blaze with a slight flame above the open 

 orifice. Indeed, with the sample of oil which did not emit sufficient 

 gaseous vapor to become kindled at a temperature below 125°, it re- 

 quired dexterous manipulation to so apportion the gaseous vapor and 

 the atmospheric air as to exhibit the faintest action of an explosive 

 character. 



Continuing the experiment with the kerosene at a still higher tem- 

 perature than 212°, by pouring it into an iron ladle over a hot fire, 

 the gaseous vapor arose therefrom still more rapidly, until it became 

 a visible smoke ascending regularly in a column from the ladle even 

 whilst heated red-hot, without becoming kindled into flame until a 

 lighted taper wag brought into contact with it ; then the gaseous 

 vapors became resolved into a bright column of steady flame without 

 any evidence of an explosive tendency. 



Whale oil, tallow, rosin, and pine sawdust were similarly exposed 

 in the same heated ladle with precisely similar results, showing that the 

 kerosene was no more explosive than either of these substances, and 

 that they all alike became decomposed at a high temperature into 

 their constituent elements of carbon and hydrogen, or carburetted 

 hydrogen gas. One measure of this inflammable gas is found to form a 

 new chemical combination with about three measures of atmospheric 

 air when kindled, and to exhibit the phenomenon of an elongated 

 flame whilst the combination is taking place between the ascending 

 particles of the surface of the gas and the particles of air in immedi- 

 ate contact therewith. This result is manifested in the form of the 

 flame of a lamp or gas-burner. But if one measure of carburetted 

 hydrogen be thoroughly mixed with four or five of atmospheric air, 

 so that the particles be all brought into intimate contact with each 

 other, then the combinatien takes place simultaneously throughout, 

 producing the sudden and violent expansive action denominated an 

 " explosion." In order, therefore, to produce an explosion of a lamp 

 or of any other vessel, it is only necessary to mix the gases of de- 



