CHAPTER IV 



THE MAGIC LANTERN WITH THE LIME LIGHT 

 AND ITS USE 



150. Apparatus and material for Chapter IV : 



Suitable room with screen (Ch. XII) ; Magic lantern with a suit- 

 able lamp-house and a lime-light burner (fig. 56-59) ; Cylinders 

 of compressed Oxygen and Hydrogen ( 154-155); Lime or other 

 refractory substance for giving the light ( 153, 157); Oxygen 

 generator and ether saturator ( 177-179); Objective shield (fig. 

 14, 62, 169); Tubes for making the connections ( 159, i59a); 

 Flash-light, screw drivers and pliers, asbestos-patch gloves (fig. 61) ; 

 lantern slides, etc.; Matches or gas lighters ( 160). 



151. For the discovery that oxygen and hydrogen burning 

 together give a very hot flame, and that dazzling light is produced 

 by directing the flame against lime, etc., and the application to the 

 magic lantern, see the Appendix. 



For works of reference see Chapter I, 2. 



THE LIME LIGHT FOR THE MAGIC LANTERN 



152. The Magic Lantern used with the lime light is in every 

 way like the standard magic lantern with the direct current arc 

 lamp with the single difference of the source of light. 



153. The lime light. This is one of the most brilliant avail- 

 able lights for projection purposes. It is produced by directing 

 the exceedingly hot flame of hydrogen burning in oxygen against a 

 piece of unslaked lime. The oxy -hydrogen flame in itself is not 

 brilliant, but the heated lime gives a light of dazzling brilliancy 

 from a very small area ; hence it is especially well adapted for pro- 

 jection with the magic lantern and the projection microscope. 



If the candle-power of a lime light is compared with the other 

 lights used for projection it will be seen that it stands third, sun- 

 light being first and the arc light second. 



Hydrogen is not always used, but illuminating gas, the vapor of 

 alcohol, ether or gasoline sometimes takes its place. 



Unslaked lime is not the only refractory substance which gives 

 great incandescence. Zirconium discs and discs made of the mix- 



