SCIOPTICON MANUAL. 



159 



shape for entering and clearing the flat mouth of the jet. 

 The wooden base-plate" .B, the bottom of which is shown at 

 Fig. 41, holds the nozzle n, which receives into its middle 

 aperture the current of oxygen gas from 0, and into its 

 side aperture either alcohol or hydrogen gas from H. The 

 lime Z/, in its holder P, is let down the open chimney of 

 the Sciopticon and held in place by the socket k, the elon- 

 gated top of which serves as a guide to the stem, a rest for 

 the lime cradle u, and a shield from the alcohol wick. The 

 base-plate of the socket is pushed under the screw-heads, 

 into contact with the nozzle n, and its angle and its height 

 are such as to bring the lime disk into proper position. 



Fig. 41. 



The lime disk is I of an inch thick, and 2 inches in diam- 

 eter. It lies loosely in its cradle u, so that lifting the back 

 with the thumb and finger half an inch or so, brings down 

 to the jet a new but hot place in the lime. This operation 

 is not hard on the fingers, because the move is so easily and 

 quickly made, and at a place in the non-conducting lime 

 most distant from the jet. The handle q, turned back from 

 the heated current, gives us control of the lime holder, so it 

 can be let down the Sciopticon chimney into its socket k, 

 Fig. 42. This height is convenient, but not essential in the 

 Lime-light Sciopticon, Fig. 43. For other lanterns the 

 handle is hinged lower, as 



