SCIOPTICONMANUAL. 83 



and pasted on the glass. Glass may be smoked or cov- 

 ered with opaque paint, and diagrams scratched upon it 

 with a needle-point or sharp knife; the light passing- 

 through these lines appearing on the screen as a white 

 chalk diagram on a blackboard. Still another way of 

 preparing diagrams is to dissolve gelatine, such as is 

 used in cooking ; strain, and pour it over the glass, form- 

 ing a thin film on its surface. When this is dry, the dia- 

 gram is scratched on as before, and soft lead rubbed over 

 the lines. Mottoes may be photographed on glass, and 

 then colored, or the designs drawn with the pen or 

 brush, and colored. 



The Sciopticon is extremely well adapted for experi- 

 ments and amusements, as its front lens can be drawn 

 out, giving ample space for the introduction of figures 

 and such like. Small china and wooden dolls, with but 

 slight tissue-paper dress, may be made to twirl or move 

 about in many curious ways; those with perfect faces 

 are the best. They of course must be suspended by a 

 silk or wire attached to the feet ; but a hint is sufficient. 

 Lizards, fish, and insects in the tank are always pleasing 

 because they move. When one has but few slides, the 

 entertainment may be varied by introducing some of 

 the home-made objects, thus affording much amusement, 

 with but slight expense and trouble. 



CHAPTEE VII. 



CHEMICAL EXPERIMENTS. 



CONTRIBUTED BY PROF. HENRY MORTON, Ph. D. 



President of the Stevens Institute of Technology, Hoboken, N. J. 



IN addition to the use of the magic lantern in its 

 original office of exhibiting pictures, it will admit of a 

 great variety of applications which enable the operator 



