INTRODUCTION. Xlll 



How to Secure the Fullest Advantages of 



the Oil light and of the Lime Light, 



all at the Least Expense. 



The portion of the Gas Sciopticon shown above, includ- 

 ing the triple jet, is all that is necessary for one having 

 the Oil Sciopticon complete to have the Gas Sciopticon 

 also complete, for the condenser, objective and draw-front 

 are perfectly suited to either. The Lime light in the 

 Oil-light Sciopticon (see Manual, p. 160) is not at its 

 best, because it is somewhat inconvenient, and the clamp 

 and the automatic cut-off cannot be attached to it ; neither 

 is the Lime-light Sciopticon with a Sciopticon lamp and 

 flame chamber sliding into it a perfect arrangement. 

 But, with the Oil Sciopticon complete, and with the 

 Sciopticon and jet as shown above, either of them, with 

 the lenses and draw-front, is at its best, and the cost 

 of both is but seventy dollars, or sixty-five without the 

 automatic cut-off. 



