When fwimming in a B A S N of OIL, &c. 165 



an equilateral triangle, having its wick in the perpendicular 

 which bifedls any of the fides, either the vertex or fide will be- 

 come tYitJiern, and keep hindmoft, according as the wick is placed 

 neareft the one or the other. Lamps, fo conftrudled, are found 

 alfo to circulate upon their arrival at the fide of the veflel, when 

 the leading point turns away fronx the glafs, as it commonly 

 happens. 



Whatever be the caufe of the failing of the lamp diredlly 

 foreward, the perpetual circulation, after it arrives at the fide^ 

 feems to proceed from the force, which formerly impelled it, 

 ftill adling in the fame manner, but in a diredlion inclined to 

 that of the corpufcular attra(5lion, which foi-ms the vinculum ; 

 and it is evident, that this inclination will be greater or lefs, ac- 

 cording as the leading point is more or lefs averted from the 

 glafs. When it fo happens that the leading point and vinculum 

 coincide, it fliotild feem that both forces, jufl now mentioned, 

 muft urge the lamp in a diredlion perpendicular to the fide of 

 the glafs ; in which cafe it muft ftand ftill, agreeable to obfer- 

 vation. 



Th£ next thing which I had occafion to take notice of, when 

 the lamp failed in a dire(?l; courfe, was, a feemingly very acflive 

 repulfion between its ftern and the oil at the furface contiguous 

 to it. This became manifeft, when very fine charcoal duft was 

 lightly fcattered around the lamp. As it then proceeded in its 

 courfe, it marked out a fpreading or diverging wake behind it, 

 entirely clear of all duft, in confequence of the particles being 

 chaced backwards, and laterally with a motion much more than 

 merely relative. 



Desirous of learning how this difperfion of the duft would 

 take place when the lamp was ftationary, I conftrudled one of a 

 fine wafer, and with an excentric wick, confifting of a foft cot- 

 ton thread doubled ; and to prevent the wafer or bafe from 

 catching fire, 1 coated its upper furface with gold leaf. When 



thi^ 



