THE CHROMOGRAPH. 749 



necessary to detail it. The layer of gelatine is made up as follows, and any 

 of the recipes will suffice. 



1. Gelatine 100 grammes, water 375 grammes, glycerine 375 

 grammes, kaolin 50 grammes. (Lebaiguee.) 



2. Gelatine 100 grammes, dextrine 100 grammes, glycerine 1000 

 grammes, sulphate of baryta q.s. (W. Wartha.) 



3. Gelatine 100 grammes, glycerine 1,200 grammes, bouillie de 

 sulphate de baryta, strained, 500 cubic centimetres/ (W. Wartha.) 



4. Gelatine I gramme, glycerine a 30 4 grammes, water 2 grammes. 

 (Kwaysser and Husak.) 



Fig. 876. The chromograph. 



The "mixture" is shaken until it cools to the point of thickening, and 

 then poured into a zinc vessel. The kaolin or the sulphate of baryta 

 makes the composition white. It can be treated again with gelatine and 

 molasses employed for printing rollers. When the proofs have been taken 

 from the frame the surface may be rubbed with a damp sponge, and then it 

 will be ready for use again immediately. The introduction of dextrine 

 facilitates the cleansing of the surface plate. 



THE CAMPYLOMETER.* 



This instrument, constructed by Lieutenant Gaumet, is very easily 

 * Kampulos, a curve ; mctron, measure. 



