H94 



concentration we so sliarply get with llio llnee iiioi'gaiiic acids the 

 phenomenon liquid-rapid coagnlation-liqnid, described in ^ 3. Tiiere- 

 fore, for the same mixture of latex, we once more delermined these 

 limits for all four acids separately, in order to get absolutely com- 

 parable figures (which figures therefore do not fully correspond with 

 those in ^^ 3 — 6, as we explained in ^ 1 and intend to discuss 

 more in detail still in ^ 8). 



The figures weie for the acid-concentration in normality : 



The lower limit of the range of coagulation is exactly the same 

 with the three strong inorganic acids, and here it is qnile clearly 

 demonstrated, tli;it, at least in this range of strongly diluled laiices, 

 the phenomenon is ruled by the positive H ions ; (he action of 

 acetic acid is somewhat weaker. 



With hydrochloric acid and nitric acid the upper limit again is 

 exactly the same; also the strips of transition (which are very 

 narrow with these strongly diluled latices) show exactly the same 

 phenomena if the same quantity of acid is added ; so the action of 

 hydrochloric acid and nitric acid in the lower range of coagulation 

 is exactly the same, whilst the limit of the upper range of coagu- 

 lation, as we have seen just now, is considerably lower with nitric 

 acid. With sulphuric acid the upper limit of the first range of coa- 

 gulation is a little higher; the difference is not important, but for 

 all that, with this exclusively <;omparative experiment, il could be 

 stated clearly, also because corresponding differences were noticed 

 in the strip of transition I3 ing above the range of coagulation. With 

 acetic acid the upper limit is much higher (at abo.ut 0.05 and Ü. 026 N, 

 see table 2) and has not been delermined again in this experiment. 



A determination of the hydrogen-ions concentration in these various 

 liquids, which would be necessary for a correct interpretation of 

 the phenomena, could not as yet take place; we only wish to draw 

 the attention to the fact, that the subsequency of the four acids at 



