SEVER PRINTING PROCHS SHS 161 
Add 500 cem (8 0z.) alcohol to the pyroxylin, and shake well ; 
then add the ether. 
Lithium chloride, cryst. 3g 23 gr. 
Citric acid 5g 38.5 gr. 
Water 5 ccm 38 min. 
Dissolve by the aid of heat, and add: 
Alcohol 30 ccm 230 min. 
Then add to the collodion gradually with continual shaking, 
so as not to precipitate any of the pyroxyline: 
Silver nitrate 24 ¢ 184 er. 
Water 30 ccm 230 min. 
Glycerine 7 ccm 54 min. 
Heat gently until the silver dissolves, and add: 
Alcohol So cen 270 min. 
If any silver is thrown out in crystals, gently heat until dis- 
solved, and add gradually while hot in small quantities to the 
salted collodion, shaking well after each addition. Allow to 
stand to ripen, and then coat. The longer the emulsion stands. 
the faster the printing and the softer the gradation of the 
prints. The following formulas are those of the leading 
experimenters and should be compounded on the above lines. 
Niederstadt.— 
Pyroxyline 28 g PANS) (oy 
Alcohol 630 ccm 10 oz. 
Ether 350 ccm 534 oz. 
Citric acid PA dUS) 16.5 gr. 
Lithium chloride, cryst. Zula, lorem: 
Glycerine 7 ccm 54 min. 
Silver nitrate 20 g 154 gr. 
Water 10 ccm 77 min. 
Geldmacher.— 
Pyroxyline 258 192 gr. 
Alcohol 590 ccm 9% oz. 
