44 



slowly as the molecular weight of the combined acids is lower. It 

 is therefore not excluded that also when giycerides of fatty acids of 

 different molecular weight occur side by side, they will present here 

 a specific saponification velocity. Experiments of the same nature 

 as have been made by Thum and Stiepel are not mentioned by 



CONNSTEIN C. S. 



§ 7. In order to be able to form an opinion about the surface 

 tensions of fats in contact with different media, 

 I made the following experiments: 



With the aid of Donnan's pipette the number 

 of drops were counted which, when a definite 

 volume of different triglycerides flowed from a 

 thin walled capillary, mounted up in water and 

 some solutions, all this at 100° 0. The arrange- 

 ment of the experiments follows from fig. 1. 

 The pipette with the tube 6' which contained 

 he aqueous solution, was heated to 100° in a 

 large glass beaker with water. During the outflow 

 of the fat the beaker was not heated to avoid 

 shaking through the boiling of the water. The 

 filling took place by the fat being sucked up 

 into the bulb B. The mouth of the capillary 

 was then cleaned as well as possible with a 

 cloth, and the tube C was fastened with a rubber 

 stopper. The whole was now carefully heated in 

 the beaker till the fat just appeared from the 

 capillary mouth, then the solution (always a 

 same quantity) was poured into C along the wall. 

 When the whole had reached the temperature of 

 100°, then the level of the fat was reduced io a by opening of the 

 cock, and then the number of drops was counted which mounted 

 in the solution in C during tlie fall of the level of the fat from 

 a to b. The diameter of the capillary mouth was about 1 mm. 

 Trilaurine flowed out from a to /; in about 4 minutes. 



During the outflow of the fat every drop remains hanging at the 

 capillary mouth till the upward pressure exceeds the tension of the 

 surface. The greater, therefore, this surface tension is, the fewer 

 drops will get detached when a definite volume of the fat substance 

 flows out, and the smaller the number of drops that will mount in 

 the aqueous liquid. When we disregard the difference in specific 

 weight of the different triglycerides, the tension of the surface of 



Fig. 1. 



