682 



('(11111(1 wiili inixdiies lie\oiid 50°/,, ialex, to lie lairly coiislant al 

 (•.012 N. We should beai' in miiui, ihat iliis means tlie acidity of 



X X XX 



Fig. 2. 



ilie lijdrocliioric' acid added, which lias to be increased with the 

 oriSfinal acidity of the latex, recaicnlaled on the final mixlnre. For 

 mixtures, containing less than 50 ° „ lalex, this hotlom-iimil ol 

 coagulation is regularly lower. Because of reasons inenlioned above, 

 the observations could not be made so sharply that ihe relation 

 between rnbber-concentiation and limit of acidity a|)peared quite 

 clearly, but especially with (he lower concen(ra(ions the small 

 irregularities may be considered to be due to observation errors, 

 and we may assume that the lowering of this limit is inversely 

 proportional to the latex concentration. 



With mixtures containing over 807o latex to which more acid is 

 added we always get a strong coaguhim, and so from the beginning 

 we are in the range of coagulation, which fairly occupies the whole 

 triangle of P^ig. 1. At 757o la'ex we get the first indications (hat 

 another phenomenon is about to appear, because the coagulum at 

 first is hard, with more acid (about 0.05 N) soft or even like pap, 

 and only with a still larger quantity of acid hard again. A distinctly 

 liquid range only appears with mixtures with 65'/„ latex and less. 



The strip of coagulation between both liquid ranges, Ihe lower 

 range of coagulation, regularly decreases in latitude at lower latex- 

 concentrations, but still remains distinctly perceptible even at the 

 lowest concentrations (1° , latex). In (hose very diluted liquids (he 



