SCIOPTICON MANUAL. 31 



der, so as not to be anywhere in contact with it. The ring shuts 

 over the end of the cylinder like the cover of a tin pail. To re- 

 move the condenser, the extension front is drawn off, and the stage 

 o is lifted out of its place. 



s Lamp cup for kerosene oil. It holds three gills, or enough to 

 last about 4 hours. "When it has to be moved about much, it is 

 better not to fill it more than two-thirds full, for if any oil gets out- 

 side, it gives off its offensive smell ; while if there is no oil outside 

 there is no smell from it in the least. "When packed for transpor- 

 tation, the oil should be thoroughly drained off. 



t Nozzle to admit the oil. It is large, so that if a wick is care- 

 lessly turned down into the cup, it can be fished out with a bent 

 wire. 



u Side of one of the two tubes, showing how the conduction of 

 heat downwards is counteracted by breaking the connection in the 

 metal. It is made of tin, for the reason that it is a slower conductor 

 than brass. 



v v Tops of the two tubes. They carry No. 8 wicks, which are 

 an inch and a half wide. The lamp being taken out, the wicks are 

 pushed down the tubes till they are caught by the ratchet-wheels 

 and drawn down. Should a loose thread of the wick get clogged 

 in the wheels it must be drawn out and cut off. The ratchet-wheels 

 could be made to bear tighter on the wicks by pounding gently 

 along the bottom of the tubes, but such a necessity is not likely to 

 happen. 



w w Buttons for adjusting the wicks; both are turned inward 

 to raise the wicks, arid outward to draw them down. 



x Spring for holding the lamp. 



z Stop, preventing the lamp from sliding in too far. 



A B Portions of the cylinder not cut- away, seen beyond the 

 condenser and flame-chamber. 



C Portion of the cylinder turned up, to give free ventilation all 

 about the flame-chamber. 



D Portion of the cylinder turned down and supported by the 

 wooden frame. 



E E' E" Bottom of the flame-chamber. It is not supported by 

 contact with the lamp, thus avoiding the conduction of heut down- 

 wards. The slot through which the flame ascends is two inches 

 long by half an inch wide. E f answers to the deflecting cap of a 



