When fwimming In a B A S N of OIL, Sec. 171 



handling it ; and, after the wick is touched v/ith a drop of oil, 

 it is ready for being lighted. For this purpofe, a bit of pack 

 thread, which has been fteeped in oil, is a cleanly and conve- 

 nient match, and Iheds no impurities on the oil, as a candle or 

 wax taper would do. 



When you want the lamps to circulate, the oil muft be very 

 pure, and brought into full conta6l with the lides of the glafs. 

 The oil, and the bafon or falver, fliould all be allowed to come 

 to the fame temperature, between ^^° and 60° of Fahrenheit. 

 For if any part of the brim be much hotter than the reft, the 

 lamp, on arriving there, will leave the fide, by the current ifTu- 

 ing from the heated part forcing it away. 



Sometimes the lamp, when failing, veers a little into a diffe- 

 rent diredlion, by the bafe altering or warping by the fcorching 

 heat of the flame, which determines the flream to flow out moft 

 copioufly at a different part of the bafe. 



In the melted greafe which lies round the wick of a common 

 candle when lighted, there are fometimes obferved atoms, which 

 have been left by the fnuffers, moving to and from the flame 

 continually. Thefe motions have been conceived by fome as 

 occafioned by attra(5lions and" repulfions, in confequence of an 

 eledlrical quality imputed to the flame. It fliould feem, how* 

 ever, that they depend merely upon oppofite currents at the flir- 

 face, and immediately below the furfacc of the melted greafe, 

 according to the principle above explained. 



X 2 VIL 



