12 



blades continue in full vigor after such ripening of the seeds, they are no crite- 

 rion by which to judge the ripeness of the cane juices. When the leaves hegin 

 to turn red is the only true standard for determining the ripeness of the juices. 

 When, therefore, the canes are perfectly grown we see that there are far less 

 gum, dextrine, and acid, and much more sugar in them. 



2. But still there will be salts and enough of gums and acids to interfere 

 with the granulation, and they must be destroyed during the boiling process. 

 How can this best be done ? 



PROPER MODE OF MAKING SUGAR. 



The great question is, how can sugar best be made from the northern cane ? 

 The chemist of the Department has investigated this question pretty fully, and 

 we take an extract from that part of his report which refers to sugar-making by 

 the masses : 



'^Defecation, or clarification. — Several modes have been adopted or proposed 

 at different times for effecting defecation. That usually employed is lime, The 

 temp(!rature of the juice is raised, milk of lime (whitewash) is added until the 

 reaction is faintly alkaline to litmus paper, and the juice is then boiled for a 

 short time. Th(; heat is then shut off, Avhen clarification rapidly takes place. 

 A thick green scum rests on the top of the pan, whilst heavy matters sink to 

 the bottom. This treatment separates all matter capable of precipitation by 

 lime at the boiling temperature. The lime protects the cane sugar, but decom- 

 poses a portion of the uucrystallizable sugar if it is present. This treatment 

 does not remove all of the nitrogenized matter, so injurious to crystallization, all 

 of tlit^ gum, nor all of the salts. 



" The juice is then filtered through animal charcoal. This removes a portion 

 of the lime, all of its coloring matters, and certain of the salts, without mate- 

 rially lessening the amount of the sugar. Of course all of its solid matters in 

 suspension are removed by the filter. 



" The juice is then again subjected to a boiling temperature, care being taken 

 that it contains enough lime to react faintly alkaline. Its Avater is, of course, 

 driven off, and the lime acts upon the nitrogenized substances, at the boiling 

 temj)erature, so as to decompose them, which is shown by the ammonia given 

 off at this stage of the process. Other substances are at the same time scpa 

 rated as a scum, M'hich is removed. It is very important to observe that when 

 grape sugar is present the lime decomposes it, and that this action is stronger 

 the higher the temperature of the boiling liquid. Brown compounds of lime 

 with the products of decomjjosition of the grape sugar are formed. I bcilieve 

 that this is the source of the difficulty which farmers have had with the sorghum 

 iuice when lime has been used for defecation. 



"The juices operated upon have been abundant in grape sugar. If no lime 

 has been used, the nitrogenized substances are not sufficiently separated, while, 

 if lime has been used, it has acted upon the grape sugar to produce an abun- 

 dance of deleterious substances. In either case there are present at the close 

 of the process substances which stand in the way of crystallization. The remedy 

 against this last evil consists in obtaining a cane which produces a juice as free 

 from grape sugar as possible." 



After the juice is boiled down just so low as to permit it to flow freely through 

 the animal-charcoal filter, it should be filtered a second time. " This second 

 filtration," says the chemist, " removes coloring matter, a large portion of the 

 lime, nitrogenized matters, and small quantities of certain salts, and leaves in 

 the juice some organic matter (gum?) and certain mineral salts. It is not sub- 

 jected to any further purification, but is rapidly boiled down to the point of 

 crystallization." 



