721 



was shaken with previously warmed (cooled) condnctivit}^ water 

 and then fdtered ra[»idly into the resistance vessel. 



As O-point was taken the moment that tlie irregular initial reaction 

 was over and tlie bridge readings could take place accurately. 



Subjoined are found some of these measurements. (See p. 720). 



In this manner the following constants were obtained for different 

 acid anhydrides. 



Hydratation-constants of the fatty anhydrides. 



This table contains a resume of the constants obtained at an 

 anhydride concentration of 0.01 —0.02 normal. We chose this small 

 concentration, because it had been noticed by Sidgwick and his 

 coadjutors') that the constant decreases when a much greater con- 

 centration is taken and also because the higher fatty acids were 

 soluble to the extent of about 0.03 normal only. 



Only under these conditions could the constants obtained be com- 

 pared mutually. 



a. From these data it follows in the first place that the intluence 

 of the temperature is about the same for the fatty acids mutually : 



— for acetic acid = 5.0 ^l 



propionic „ =5.3 

 n. butjTic ,, := 5.2 

 isobutyric ,, =5.0, 



and differs considerably from that found previously for the cyclic 

 anhydrides. ') 



1) See. 97, 732 (1910), 101, 1708 (1912) and 103, 1959 (1913). 



2) This has been deduced from the above measurements in connexion with those 

 of RiVETT and SmcwicK (I.e.) and Orton and Jones. Soc. 101, 17Ü8 (1912). 



3) Recueil 31, 80 (1912). 



