238 Sir Frederick Abel - [March 13, 



explosion, and the oil, becoming ignited, burnt portions of the table 

 on which it fell. 



A careful investigation of accidents of which the foregoing are 

 illustrations,* together with a critical examination of the construction 

 of various lamps, and the results of many experiments have, up to the 

 present time, led the lecturer and Mr. Eedwood to arrive at several 

 definite conclusions with respect to the immediate causes of lamp- 

 explosions and to certain circumstances which may tend to favour the 

 production of such exi^losions. 



If the lamp of which the reservoir is only partly full of oil, be 

 carried, or rapidly moved from one place to another, so as to agitate 

 the liquid, a mixture of vapour and air may make its escape from the 

 lamp in close vicinity to the flame, and, by becoming ignited, deter- 

 mine the exj^losion of the mixture existing in the reservoir. This 

 escajje may occur through the burner itself, if the wick does not fit 

 the holder properly, or through openings which exist in some lamps 

 in the metal work, close to the burner, of sufficient size to allow flame 

 to pass them readily. A sudden cooling of the lamp, by its exposure 

 to a draught or by its being blown upon, may give rise to an inrush 

 of air, thereby increasing the explosive j)roperties of the mixture of 

 vaj^our with a little air contained in the reservoir, and the flame 

 of the lamp may at the same time be drawn or forced into the air- 

 space filled with that mixture, especially if the flame has been turned 

 down, as the latter is thereby brought nearer to the reservoir. The 

 sudden cooling of the glass, if it had become heated by the burning 

 of the lamp, may also cause it to crack if it is not well annealed, 

 and this cracking, or fracture, which may allow the oil to escape, 

 may convey the idea that an explosion has taken place. If the 

 evidently common practice is resorted to of blowing down the 

 chimney with a view to extinguish the lam]), the efi'ects above in- 

 dicated as produceable by a sudden cooling may be combined with 

 the sudden forcing of the flame into the air-sj)ace, and an exj^losion 

 is thus pretty certain to ensue, especially if that air-space is con- 

 siderable. If the flashing point of the oil used be below the 

 minimum (73° Abel) fixed by law, and even if it be about that 

 point or a little above it, vapour will be given off comparatively freely 

 if the oil in the lamp be agitated, by carrying the latter or moving it 

 carelessly ; the escape of a mixture of vapour with a little air from 

 the lamp, and its ignition, will take place more readily, but on the 

 other hand it will probably be feebly explosive, because the air will 

 have been expelled in great measure by the generation of petroleum 

 vapour. If the flashing point of the oil be high, the vapour will be 

 less readily or copiously produced, under the conditions above in- 

 dicated, but, as a natural consequence, the mixture of vapour and 



* Mr. Alfred Spencer, of the Metropolitan Board of Works, has obligingly 

 furnished me with the official details of several of the accidents above referreil to. 

 — F. A. A. 



