234 Sir Frederick Abel [Marcli 13, 



has also been established by careful observations which Beilsteiu 

 has instituted, that some American oil which is specifically lighter 

 than the Baku oil is not so readily carried up to the flame as 

 the latter, by the capillary action of the wick. Mr. Boverton Eed- 

 wood has carried out some instructive exjDcriments, employing 

 different kinds of wick as siphons, and measuring the quantity of 

 different descriptions of oil drawn over in corresponding periods of 

 time by the different wicks. These showed that the Baku kerosine was 

 drawn over with decidedly greater rapidity than samples of American 

 petroleum of ordinary quality, but that on the other hand, a sample of 

 American kerosine of the highest quality exhibited a corresponding 

 superiority over the Baku oil experimented with. The nature and 

 behaviour of the wick plays a most important part in determining the 

 efficiency and also the safety of a mineral oil- or petroleum-lamp, as 

 will be presently pointed out. 



Ever since paraffin or petroleum oils, w^hich may be included 

 under the general designation of mineral oils, first assumed im- 

 portance as illuminating agents, accidents connected with their use 

 have continued to claim prominence among those casualties of a 

 domestic character, which tend to cast suspicion on the safety of the 

 material dealt with, or of the method of employing it, under the 

 ordinary conditions fulfilled by its careful use. 



The employment as an illuminant of the most volatile portions 

 of petroleum which are classed as spirit or naj)htha has been chiefly 

 limited to the wickless Holliday lamp, in which a small continuous 

 supply to a chamber heated by the lamp flame which surrounds it, 

 furnishes the vapour which maintains that flame, and to the small so- 

 called sj^onge lamps or benzoline lamps, of which the body is filled 

 with fragments of sponge, and which is intended to be charged only 

 with as much spirit as the sponge will hold thoroughly absorbed ; the 

 small flame at the toji of the wick-tube being fed by the gradual 

 abstraction of the liquid from the soaked sponge, by the wick of 

 sponge or asbestos which fills the tube. An ingenious application 

 of naphtha as an illuminant consists in filling a reservoir with 

 sponge fragments, kept soaked with the spirit, the vapour of which 

 descends by its own gravity through a narrow tube at the base of the 

 reservoir, and issues from a fish-tail burner under sufficient pressure 

 to produce a steady flame for some time. 



The only real danger which may attend the use of the little 

 sponge lamps arises from accidental spilling of spirit used for filling 

 them in the neighbourhood of a flame, or from carrying out the 

 operation of filling in the vicinity of a light. Indeed, such casualties 

 as have been attendant upon the use of petroleum spirit as an 

 illuminant have been mainly connected with the keeping and handling 

 of the supplies of this very volatile liquid, and are largely attributable 

 to want of caution or to forgetfulness. The salutary regulation pre- 

 scribed by law, that vessels containing the f2^^'^"i^ sliall bear a 

 conspicuous label indicating its dangerous character, lias undoubtedly 



