THE ACTION OF HEAT, ALKALIES AND ACIDS 



267 



Experiments by Cross^^ gave the results tabulated below. In these 

 experiments neutrality refers to the indication afforded by litmus. 



Hence as the quantity of hme used in defecation increases, so does the 

 quantity of hme salts in solution. It was also demonstrated by Cross that the 

 action of sodium carbonate of phosphates in removing the lime salts is very 

 small. 



The Rise in Purity of Cane Juices due to the Combined Action of Heat and 

 Lime. — -A rise in purity in a cane juice can only be obtained by the removal 

 of non-sugar from solution. Removal of suspended solids does not mean 

 a rise in purity. In the experiment quoted above, the juice contained 

 16 "O per cent, of gravity soUds, and polarized 13 '12, being of polarization 

 gravity purity 82-00. With the addition of 0-052 grams of hme, the 

 gravity soUds become 16 • 048, and the precipitate being 0-310 gram there are 

 left in solution 15-738 gravity sohds. The polarization gravity purity must 

 now be 83-26. For other quantities of lime the calculated purity wiU be : — 



The weight of the material removed by filtration alone was determined for 

 this juice, with the result that the purity of the filtered juice was found to be 



