W. A. Davis 



15 



glutose formed has increased, the divergence is far greater between 

 the two sets of values, than in the earlier experiments (23 to 72 hours, 

 Table III). 



B. Ex'periments ivith Invert Sugar. 



Series IV. The following set of experiments was made by 

 Dr H. Limbosch. 



A 1 % solution of saccharose (solution A) was prepared by dissolving 

 5-000 grms. of the pure sugar in 500 c.c. of water. 



Rotation in 400 mm. tube, af = + 2-686°. 



100 c.c. of solution A were inverted by heating 10 minutes with 

 10 grms. of citric acid. The solution was exactly neutralised by sodium 

 hydroxide, and diluted to 200 c.c. = solution B. 



* The polarisation calculations were made by assuming that the change of rotation of a 1 % solution 

 of saccharose on inversion is 3-488° in a 400 mm. tube at 20°. 



The values given in Table VI show that even when the basic lead 

 acetate is left 10 minutes in contact with the invert sugar solution and 

 is then precipitated by sodium carbonate the loss of laevulose is less 

 than 1 % of the sugar present. After 60 minutes, however, the loss 

 of sugar becomes quite appreciable, whilst after 24 hours the loss 

 is considerable. It is noteworthy that in the above experiments the 

 polarisation values are slightly higher than the reduction figures. 



{Received February 15th, 1916.) 



