APPENDIX I 



THE MAKING OF LANTERN SLIDES 



THOUGH this is not strictly a "Laboratory Art," the science 

 teacher will find it a great convenience to be able to prepare his 

 own slides almost at a moment's notice, and the application of the 

 lantern to his teaching will be greatly extended. 



Lantern slides may be prepared in several ways, but roughly 

 these may be segregated into four main groups. 



1. Slides prepared by photography. 



2. Slides prepared by tracing or sketching on ground glass 



and subsequently " clearing " by various methods accord- 

 ing to the requirements of the case. 



3. Slides prepared by tracing or sketching upon ordinary 



plain glass with special ink. 



4. Slides consisting of mounted objects, such as crystals, 



leaves, etc., usually, however, more suitable for projection 

 with the aid of a lantern microscope. 



i. In some cases the "negative" may be suitable for the 

 making of a lantern slide without further trouble, and in many ways 

 the manufacture of lantern slides may be shortened according to 

 the purpose of the product, but the following method will give a 

 fairly complete outline of the full process, from which departures 

 may be made as the exigencies of time and material demand. 



The process of preparing the negative will vary according to 

 the object being photographed. Apparatus is difficult to photo- 

 graph owing to reflections in the glass parts, while books are 

 difficult because of the trouble of holding them in position during 

 photography, and at the same time efficiently lighting the page to 

 be copied. 



Apparatus should be set up on a bench out of the reach of 

 direct sunlight, but in a position of fair illumination if possible it 

 should not be placed facing a window. The more diffused the 



