11 



been done the Sciopticon, not only by bungling imitations 

 and second-hand sales of old forms of it, but by saddling it 

 with poor slides. 



To extend the use of the Sciopticon, particularly as a 

 "home influence, worthy of all praise (See Introduction, 

 page xix), we will gladly furnish good, clear slides, of our 

 selection from this class, at extremely low prices. 



IMPROVEMENTS IN APPARATUS. 



Having an inventor's pride in the Sciopticon, with its 

 accessories, I naturally strive to improve it in every particu- 

 lar possible. New features, however, are not pushed into 

 notice till thoroughly tried and found worthy of approval. 

 Of course, many promising theories fail of giving satisfac- 

 tion when reduced to practice. For example, my early 

 three-wick theory, coeval with my first patent, failed to 

 meet my expectations. Wider wicks gave more candle 

 power and more heat, but not more illumination on the 

 screen. Oxygen, supplied between the flames, brightened 

 them beautifully, but the wicks soon burned away, and the 

 adjacent parts became overheated. My efforts to advan- 

 tageously substitute Hydrocarbon vapor in Burner No. 1 

 have not yet proved fully successful, though hope still 

 survives. But space would not allow a full enumeration of 

 the many experiments involved in reaching a few well- 

 assured improvements. 



The following settled modifications, not previously de- 

 scribed, are here explained, not only for the purpose of 

 calling attention to them, but of showing the operator how 

 to use them. 



