no MANAGEMENT OF THE LIME LIGHT [Cn. IV 



lessened, and one must move the lime a little so that a new surface 

 may be acted upon. 



In practically all the modern burners there is a screw mechanism 

 for rotating the limes and for raising and lowering them (fig. 59 S). 

 With a little experience one learns by the looks of the screen 

 light when to turn the lime. If the limes must be handled, use 

 tongs or asbestos-patch gloves (fig. 61). 



165. Turning out the light. Always turn off the oxygen first, 

 then the hydrogen. Never turn off the hydrogen until after the 

 oxygen is turned off. 



Perhaps it will help to remember the order by keeping in mind 

 that (i) the Hydrogen is the first to come and the last to go. (2) 

 And the Oxygen, like the best in human nature, is last to come and 

 first to go. 



MANAGEMENT OF THE LIME LIGHT MAGIC LANTERN FOR AN 

 EXHIBITION OR DEMONSTRATION 



166. Preparation for an Exhibition. Before the exhibition 

 the operator should see that everything is in perfect order and 

 readiness. The gas cylinders should be connected with the burner, 

 and a perfect, fresh lime should be in position in the burner. The 

 box of limes should also be at hand in case anything goes wrong 

 with the one in the burner. 



167. To start the light. It takes much longer than for the 

 arc lamp. It is usually about half a minute before the brightest 

 light possible is produced, and one must not forget the precaution 

 to warm the lime before subjecting one spot to the full power of the 

 O-H jet. 



Light up as directed above ( 160). 



If there is a snap and the light goes out, turn off the oxygen, and 

 relight the hydrogen. Turn on the oxygen slowly until the best 

 light is obtained ( 160). 



168. To put out the light. Turn off the oxygen first, then the 

 hydrogen ( 165). 



