SALTER DUPARER 195 
A casein paper can be made as follows: 
Ammonium chloride 4g Slee 
Sodium citrate, neutral 40g 310 gr. 
Water 400 ccm 6¥4 oz. 
Dissolve, and add: 
Casein 40 ¢g 310 gr. 
Ammonia  )S0i 384 min. 
Water | 350 ccm . SY oz. 
Warm this until dissolved, then add: 
Silver nitrate 70g 538 gr. 
Water to 1000 ccm 16 oz. 
This paper will not keep well, but can be made more stable 
by immersion in 3 per cent solution of citric acid. 
SENSITISING LEATHER, Fasrics, ETc. (Cobenzl).— 
Ammonium chloride 20 g 154 gr. 
Gelatine 5¢g 38 gr. 
Water 800 ccm 13 oz. 
Soak the gelatine in the water, add the chloride, melt with 
heat, and add to: 
Soluble starch 20 g 154 gr. 
Water 200 ccm 5) Ore, 
The material should be immersed in this until thoroughly 
soaked, then hung up to dry; if the fabric is thick and soaks 
up much of the liquid, more water should be added. When 
dry, it is silvered on: 
Silver nitrate 205.8 302 134 on, 
Citric acid 103 g 791 gr. 
Water 1000 ccm 16 oz. 
The fabric should be laid on the bottom of a large dish, a 
glass rod placed on the top, the liquid poured over, and the 
rod rolled to and fro; this saturates the cloth without the 
necessity of touching it with the fingers. Artificial light 
should be used, and the drying should be as rapid as possible. 
