132 LANTERN WITH ALCOHOL LAMP AND MANTLE ICn. V 



(3) When the torch is in place and wet with alcohol, open the 

 stop-cock from the supply tank (fig. 73 R), and then light the 

 torch. The alcohol flame will heat the burner and stand-pipe, and 

 the alcohol in the stand-pipe will be vaporized and pass over 

 through the small pipe to the burner where it will catch fire and 

 burn. Open the air intake partly. In using the lamp this air 

 intake must be regulated as for a Bunsen burner, the more pressure 

 the more the valve must be opened. 



Soon the mantle should begin to glow brightly from the burning 

 vapor in the burner. When this occurs commence to put pressure 

 on the alcohol tank (fig. 73 W). This is done by connecting the 

 pressure apparatus by means of the rubber tube to the alcohol 

 tank, at T, (fig. 73), and squeezing the bulb. 



In case the first burning off of the torch does not start the lamp 

 one must burn it off again, but do not add the alcohol until the 

 torch or heater is out, and then use a pipette. Relight the heater 

 and it will almost surely start the lamp. 



Do not connect the pressure apparatus until the mantle com- 

 mences to glow. If pressure were on the alcohol tank at first the 

 liquid alcohol would be forced over from the stand-pipe into the 

 burner and would run down on the torch and upon the table. 

 Remember that alcohol is very inflammable and also very unman- 

 ageable \vhen it is on fire, so be exceedingly careful. 



(4) As soon as the mantle begins to glow brilliantly consider- 

 able pressure can be put on the alcohol tank. The greater the 

 pressure the wider must the air-intake at the burner be opened and 

 the more brilliant will be the light; but as the pressure increases 

 the lamp roars more loudly until, when the pressure is considerable, 

 it roars like a young blast furnace. By watching the results one 

 can avoid the excessive noise, and still get a brilliant light. 



217. Management of the exhibition. This is in general like 

 any other magic lantern, but as the light depends largely on the 

 pressure regulation, one must be careful to keep up the proper 

 amount of pressure during the entire time. Do not expect too 

 much of this light. It gives fairly good lantern-slide images for a 

 screen from two to three meters (six to nine ft.) square. As the 



