THE BOOK OF THE LANTERN. 133 



glass plate, fix it on the pneumatic holder, hold it level, 

 and ponr a small pool of emulsion in its centre. By inclin- 

 ing the plate a little, the pool will run to the two further 

 corners, and can afterwards be guided across the whole 

 plate with the help of the glass rod. The plate is then 

 slid on to the slab, where it will speedily set, and the glass 

 rod goes back into the jug. Each plate is treated in the 

 same way until the slab is full, by which time its first 

 occupants will have set, and can be reared up to dry in 

 shelves, or a proper drying cupboard. The glass chosen 

 should be as thin and as free from bubbles as possible, and 

 can be of the standard lantern size, 3 J by 3J inches. But 

 as experience is gained the operator will find it more con- 

 venient and economical of time to coat plates 6 J by 6 \ inches, 

 which can afterwards be cut across twice with the dia- 

 mond, to form each four lantern slides. 



GELATINO-CHLORLDE PLATES. 



My own favourite process for lantern slide making is the 

 gelatine-chloride, which has many good points to recom- 

 mend it. It is suitable only for contact printing, there- 

 fore the negatives used must be small ones only. Capital 

 chloride plates can be purchased nowadays ; but for those 

 who prefer to make their own, I can confidently recom- 

 mend the following formula : Mix up the three solutions 

 A, B, and C. 



("Gelatine 



( Water (distilled) .. 



Silver Nitrate 



Water (distilled) .. 



Ammonium Chloride 



Water (distilled) .., 



300 grains. 



4 ounces. 

 240 grains. 



4 ounces. 

 100 grains. 



2 ounces. 



