420 



acid series, that are soltihlc in water. The alcohols of fattj acids 

 behave in a remarkably uniform way')- With all of them the charge 

 of the solutions, if there is any, is positive. With ethyl- and propyl- 

 alcohol it begins in stronger concentrations than with butyl- and 

 amyl-alcohol ^), as was established before in the physiological labo- 

 ratory when studying the charges of homologous series; all these 

 charges are raised by sodium-chloride, the more so as the concen- 

 tration of NaCl was taken higher. 



The fatty acids present quite a different electrical phenomenon. 

 Leaving formic acid, which gives only a very low charge, out of 

 consideration, we find that acetic acid always gives a positive charge 

 in all the concentrations in which it gives any charge at all. Pro- 

 |)ionic acid, butyric acid, valerianic acid, caproic acid on the con- 

 trary have a negative sign in those weaker concentrations, in which 

 they produce a charge, as will be seen in fig. 3. 



The lowest negative charge occurs with caproic acid ; with valerianic 

 acid the curve is less deep, with butyric acid still less, while with 

 propionic aci(t it is extremely level. The behaviour of the latter 

 acid is very strange indeed ; its negative bend keeps very close to 

 the zero-line and proceeds over a considerable distance, the positive 

 line rises suddenly- up to a maximum. So the curve of this acid 

 also runs between those of acetic acid and butyric acid ; its positive 

 zone is much stee|)er than that of i)utyric acid '), whereas its nega- 

 tive zone is much less deep than that of butyric acid and accounts 

 for the absence of a riegative zone with acetic acid. All this may 

 be seen in Fig. 8, without further description. With none of these 

 acids, except with acetic acid, could we find the descending portion 

 of the positive line, because their solubility was less than that of 

 acetic acid. 



Taking them all together these various acids present the whole 

 negative and positive phase, with this restriction that practically 

 pai't of it comes to nothing; of the positive phase with the higher 

 terms of the group on account of too little solubility ; of the negative 

 phase with the lower terms for reasons of which we are entirely 

 ignorant. 



II. In the second place') we watched the influence on the charge 



1) We must perhaps except methylalcohol on account of a probable complication. 

 ») With ethyl- and propylalcohol in 0.01 n. ; with butyl-alcohol in 002 n. ; 

 with amyl-alkohol in 0.0005 n. 



») Tiiis is not noticeable on the (logarithmic) curve. 

 4) These Proc. Vol. XX, p. 1272. 



