3IAJVUAL FOR SUGAR GROWERS. 



103 



The last column gives the quantity of glucose in 

 the syrup for every one hundred parts of cane sugar, 

 or what is known as the glucose ratio. 



In the case of the vacuum pan, about to be de- 

 scribed, the inversion is but very slight. These re- 

 sults are expressed graphically in the diagram, 

 curves representing the work of the vacuum pan 

 and the concretor being added for comparison. 



o 



10 20 30 40 50 00 70 80 90 100 



Total sugar in eyrup. 



Fig, 15.— Curves illustrating the increase of glucose with increasing concen- 

 tration in various processes of sugar-manufacture. 



It is necessary here to say a few words on the 

 theory of boiling. It is well known that the tem- 

 perature at which a liquid boils depends entirely 

 on the pressure to which it is subjected. The 

 pressure to which liquids in open vessels are sub- 

 jected is the pressure of the atmosphere, and this 

 under ordinary conditions is a pressure of nearly 



