480 BOARD OF AGRICULTURE. 



So far, nothing has been found that will answer our purpose so well as these 

 sulphur bleachers ; hence I will pass over the others in silence. 



As I wish to be understood by the unlearned as well as by the student, I shall 

 not only go back to the ABC, but use tf rms not strictly scientific. If you burn a 

 piece of suljihur, a penetrating odor is produced. This odor is due to the gas 

 formed by the sulphur uniting with the oxygen of the air. This combination is 

 known as sulphurous acid gas. This gas is commonly produced by burning sul- 

 phur in air, hence called sulphur fumes. Sulphurous acid is water charged with 

 sulphurous acid gas. Pure water will take up sixty-nine times its volume of gas; 

 that is, one gallon of water, under the most favorable circurustances, will absorb 

 sixty-nine gallons of this gas. Bisulphate of lime differs from sulphurous acid 

 only in that the water contains a solution of lime. You will readily see that the 

 value of all sulphur bleachers is due to sulphurous acid gas. You will ask, then, 

 what is the use of the two last ? Why not use sulphur fumes and get this gas di- 

 rect ? Many do. But there are some objections. Sulphur fumes contain more 

 than sulphurous acid gas, and you may get things into the juice you do not, want. 

 Among these is sulphuric acid, which is not only deleterious to the products for 

 which we labor, but by union with the iron of our pans or implements, forms cop- 

 peras, which is a poison. I believe (but have not demonstrated) that sulphur 

 fumes convey coloring matter to the juice. I have never seen a syrup made by 

 fumes that would compare in color with that made by other bleachers. But the 

 great objection is that fumes can not be applied to the juice with such exactness as 

 the other two. Guess work will not give us success in this business. For these and 

 other reasons sulphurous acid and bisulphate of lime have been used. Of these 

 two, preference has been given to bisulphate of lime, since it can be made in a con- 

 centrated form, saving freight as well as evaporation. Sulphurous acid quickly 

 becomes sulphuric acid, which is very objectionable, as has been explained. 

 Another reason might be given to the sugar maker. All acids are destructive to 

 crystalization. But sulphurous acid in the presence of a base is inert. Lime is a 

 base ; hence the sulphurous acid of the bisulphate of lime can be safely used. 

 These reasons have led many to adopt this as a bleacher par excellence. Add to this 

 the fact that its antiseptic powers are superior to that of any other bleacher known, 

 and it will be easy to understand why it stands in high favor. An eminent chem- 

 ist says of bisulphate of lime : 



1. It prevents all fermentation of the cane juice. 



2. It combines so very readily with oxygen that it prevents the latter from ex- 

 erting its deleterious action on the cane juice. 



3. It is a defecating agent, clarifying the juice at about 212 deg^ F., by depriv- 

 ing it of nearly all the albuminoid and coagulable matters contained in it. 



4. It acts as a decolorizer, and prevents the formation of coloring matter 

 during the operation. 



5. It neutralizes the acids which transform crystallizable sugar into glucose. 



6. It substitutes for these acids sulphurous acid, which is inert in the presence 

 of bases. 



Whether the bleacher or lime should be put into the juice first is a disputed 

 point. I use the bleacher first, since it should be put in as soon as possible, t© pre- 



