124 



MAGIC LANTERN WITH PETROLEUM LAMP [Cn. V 



Light the wicks and turn them up moderately and allow them to 

 burn for five or ten minutes before the exhibition. This is to get 

 the apparatus warmed up. One cannot get the best light from a 

 petroleum lamp instantly, but only after it has become warm. 

 Finally turn up each wick as high as possible without having it 

 smoke. The central wicks can usually be turned higher than the 

 marginal ones. When the wicks are at their full height the chim- 

 ney, if adjustable, must also be at its full height to give the best 

 draught. 



After the exhibition is over the lamp-wicks are turned down, the 

 small flames blown out, and then the unused oil poured into a con- 

 tainer, the wicks taken out and carefully dried between blotting 



FIG. 67. NEWTON'S FOUR-WICKED, PETROLEUM LAMP KOR THE MAGIC 



LANTERN. 



(From Catalogue No. 4 of Newton r Co.}. 



The chimney is in two segments. For the maximum light after the lamp is 

 warmed up, the top segment is added. 



