CHEMISTRY OF SUGAR. 23 



glucose is obtained, together with dextro-glueose, in the fermentation 

 of cane sugar, which, under the action of the ferment, splits up into 

 equal parts of dextro and laevo-glucose. And, since the left-handed 

 rotation of the latter is greater than the right-handed rotation of the 

 former, the solution of cane sugar — which, at first, was right-handed 

 in its rotation of the plane of polarized light — after fermentation is found 

 to be left-handed, or (as it is termed) inverted; and hence the name 

 " inverted sugar," which is a mixture of these two forms of glucose. 



The formula which represents the final results in this process of fer- 

 mentation is, in 



Cane sugar -}- water. Dextro glucose. Laevo-glucose. 

 C12H22O11 + H2O = CgHigOe + CgHigOg. 



One molecule of cane sugar uniting with one molecule of water, and 

 then breaking up into one molecule of dextro- and one molecule of 

 laevo-glucose. 



This change in cane sugar is readily brought about, also, by the ac- 

 tion of dilute acids. If, to a dilute solution of cane sugar, a few drops 

 of sulphuric or hydrochloric acid be added, and the solution be heated 

 at a temperature of 90°C. (194°F.) for half an hour, it will be f nind 

 that the cane sugar will have entirely disappeared from the solution, 

 and, in its place, will be found its equivalent of inverted sugar. This 

 is the method pursued in the determination, by analysis, of tlie cane 

 sugar in juices of sugar producing plants. (See chapter on Methods of 

 Analysis.) 



It is, however, to be remembered, that this change is eflTected by 

 the heat in the presence of an acid, and very speedily in such circum- 

 stances: but heat alone effects this change very slowly, indeed, if at 

 all ; although the contrary opinion is very generally entertained by 

 those who have never subjected the matter to the test of experiment. 



A series of experiments are given in the Journal Fabr. Sucre, byM. 

 Pellet, showing the amount of inversion of solutions of cane sugar at dif- 

 erent temperatures and degrees of concentration. The experiments 

 were, in each case, continued for four days (96 hours) : 



Sugar in 100 c.c. At25°C. At 50^ C. At 75=' C. 



10 grams. .5975 grams. .3.0216 grams. 8.8100 grams. 



30 grams. .-5275 grams. 2.9200 grams. 7.1825 grams. 



60 grams. .1025 grams. .6450 grams. 5.4900 grams. 



90 grams. trace. .1-500 grams. ' 3 977.6 grams. 



It wiU be seen, that the extent of inversion was dependent upon tem- 

 perature and concentration of the solution ; and that a solution contain- 

 ing 60 grams, of sugar in 100 cubic centimeters of solution (about tlie 

 consistency of a syrup), even after four days' heating at a temperature 



