96 



The World's Commercial Products 



nowadays are principally used for refining purposes, and for table use whiter sugars are pre- 

 ferred. To obtain these the juice has to be bleached, and this is usually done by submitting i1 

 to the action of sulphurous acid, generated by roasting sulphur and passing the fumes intc 

 a tank containing the juice which may or may not have been already defecated. In eithei 

 case the sulphuring is additional to and not in place of the defecation process. 



Boiling. The clarified and filtered juice is now ready to be boiled down into syrup of suffi- 

 cient concentration to allow sugar crystals to be obtained from it. The dilute liquor is firsl 

 evaporated down to a syrup ; this is further concentrated to the pasty masse-cuite consisting 

 of crystals embedded in the thick syrupy liquor, and from the masse-cuite the crystalline suga] 

 and the uncrystallisable molasses are separated. 



In no portion of the process of sugar manufacture have such improvements been effectec 

 during recent years as in the mode of boiling, and in all up-to-date factories, the open boiling 



INTERIOR OF A SUGAR FACTORY 



pans have been replaced by modern " triple effects " and vacuum pans. The old-fashione< 

 open boiling, still employed for special reasons on some estates in the West Indies, in India 

 and elsewhere, was conducted in this way. Some four or five large hemispherical coppe 

 pans were arranged in a line above a flue so that they were all heated by a fire generated a 

 one end, directly under one of the pans. Frequently the pans or " tayches " were of differen 

 sizes, the smallest being placed immediately over the lire and the largest at the greates 

 distance. When the set is in working order all are boiling at once and fresh supplie 

 of clarified juice are introduced into the largest tayche as required, whilst each of th 

 other tayches is kept full by ladling liquor into it from the one farther away from th 

 fire. The result is a series of pans containing liquors of various degrees of concentration 

 because as the juice in No. 1 begins to concentrate it is ladled on to No. 2, from No. ! 

 to No. 3, and so on until it reaches the last pan, the smallest one, placed directly over th 

 fire. The scene in a sugar-boiling house, with the row of huge bubbling cauldrons of syrup 

 which is continually being stirred and transferred from one cauldron to another by mean 

 of long ladles, is very interesting, however much it may fall short of modern ideas. I: 

 the last tayche evaporation is continued until the mass is ready to crystallise out on cooling 

 As soon as this point is reached it is ladled out into the coolers, shallow, rectangular ston 



