689 



acid, liave heeii put logetlier in tig. 4. The liuge range of ooagu- 

 lation at acid-concentrations above 0.1 N (normal = 49 Gr. H, SO, 

 per Liter) has again t)een quite left out, and also the mixtures 

 with over 70 *, ,, latex, where coagulation constantly takes place 

 as soon as more than 0.01 N acid is added. On account of the 

 smaller number of observations, the course of the limits in fig. 4 

 seems to be somewhat irregular, yet the data are sulTicient to 



w 



Fig. 4. 



conclude, that the pappy and the liquid range, compared with 

 hydrochloric acid and nitric acid, have shrunk still more. Figures 

 of comparison are again found in ^ 7. 



We may still mention, that, starting from a mixture with 70 7, 

 latex, we get a distinct indication regarding the existence of the 

 , .irregular series", though all the mixtures coagulate; the mixture 

 with 0.04 N. acid gives a perceptibly softer coagulum than that 

 with 0.025 or 0.05 N. acid. 



^ 6. Acetic acid. 



For acetic acid — the general and usual means of coagulation 

 at rubber plantations — the course of the phenomena generally 

 speaking appears to be the same as in the previous cases, but the 

 proportions of the various ranges are quite ditferent ones. Whilst 

 with the three previous acids the whole range of the irregular series 

 lies in a narrow strip along the latex-water side, which in a re- 

 presentation like fig. 1 is hardly discernible, the irregular series 

 with acetic acid are extended to far higher acid concentrations, and 

 a triangle-figure like fig. 5 opens the best general aspect. Here 

 likewise the range of coagulation occupies by far the greater part, 

 viz. almost ', of the triangle; bul in the neighbourhood of the 



