140 CASEIN. 



and adding glycerine, syrup, molasses, fats or oils, alone or in 

 conjunction, the whole being well mixed. The quantity so 

 added depends on the degree of suppleness desired, and is 

 preferably about one-half of the mass obtained by the afore- 

 said precipitation. 



The resulting mass for the first coating can be applied 

 to paper or fabric before it has set, and forms a very flex- 

 ible, insoluble coating resembling caoutchouc. To make the 

 paper keep better it may be at once mounted on fabric by 

 pressure, or pressed between two similarly treated sheets or 

 roll lengths of paper. Of course the fabric may have been 

 impregnated beforehand, or else the joined paper and fabric 

 may be treated afterwards. 



To improve the waterproofing qualities and impart a fine 

 gloss, a second coating is applied of any convenient water- 

 proof varnish or lacquer. Colouring matters can be incor- 

 porated with the first or second coating, according to choice. 



CASEIN SOLUTION FOR COATING PAPER. 



A casein solution, suitable for coating paper and for 

 other purpose^, can be prepared, according to W. A. Hall's 

 English patent, by mixing casein (precipitated with hydro- 

 chloric acid) with 10 to 15 per cent, of its weight of sodium 

 phosphate, preferably trisodium phosphate, and 1 to 3 parts 

 of water to each 1 part of casein. 



HORN'S CLEAR SOLUTION OF CASEIN. 



A clear solution of casein, free from fatty bodies, is 

 obtained by treating a 10 to 20 per cent, solution of casein 

 with 7 to 8 per cent, of caustic potash (according to the 

 amount of dry matter), the whole being shaken up with 

 ether for a short time and run into a settling vat. The clear 

 solution of casein subsides and can be drawn oft'. 



