SUGAE. 



177 



to neutralize this will be nearly the same weight, and therefore 

 will form but 4 per cent, of the lime necessary for tempering in 

 the ordinary manner ; that is to say, 4 per cent, more lime will be 

 required by the sulphurous acid process than by the ordinary method 

 of defecation ; and this is probably little, if any, more than the syrup, 

 as it leaves the concentrators, will be able to retain in solution. The 

 lime required at Aba, if used in the same proportion to the juice as 

 at Bene Mazar, would be lbs. per clarifier, increased only to 

 Sy^Q- lbs. in neutralizing the sulphurous acid gas; it is therefore 

 expected that the deposit of sulphate of lime, which materially inter- 

 fered with the working of the concentrators last season, will be very 

 considerably reduced, if not completely removed, more especially 

 because they are not in a condition analogous to steam boilers out of 

 which only steam is taken ; on the contrary, from them at least 40 per 

 cent, of the entering fluid flows out again, and must carry a large 

 proportion of slightly soluble and suspended matters with it. The 

 rapidity of the process of getting the juice to the state of syrup, 

 when it is safe from fermentation, is best illustrated by comparison 

 with Bene Mazar. In that mill a particle of juice in travelling 

 through the apparatus remains two hours in the juice tank and 

 clarifiers, two hours in the charcoal filters, an hour and three- 

 quarters in the triple-action concentrators — in all, five hours and 

 three-quarters, while at Aba the same state is reached in less than 

 two hours, or in about one-third the time. 



" It is well known that sulphuric acid is a deadly enemy to crys- 

 tallizable sugar, and sulphurous acid being very nearly allied, it was 

 feared that its use might also be, to some extent, prejudicial. To 

 settle this point, samples of juice obtained from Egyptian cane were 

 carefully clarified in the ordinary manner with lime, and then filtered 

 through charcoal, and also by the sulphurous acid gas process ; the 

 resulting specimens of clarified juice were then analysed, and it was 

 found that the samples obtained from the latter process were to 

 a slight extent richer in crystallizable sugar ; the difference, however, 

 was very small, so that practically it became safe to assume that there 

 would be no loss of crystallized sugar through the use of sulphurous 

 acid. Inasmuch as the third boiling of molasses has to stand from 

 three months to six months before it can throw down all the crystal- 

 lizable sugar, a complete investigation into the yield of any process 

 is a very tedious business, and, in fact, can only be accurately done by 

 exact observation throughout the season's working, extending, with 

 the manufacture of all the produce, over at least seven months 

 or eight months. Nor is it possible to make any satisfactory estimate 

 of the yield of the third boiling, as it varies very much, depending 

 greatly on the state of the canes and the goodness of the original 

 clarification and concentration of the juice. I devoted one month to 

 watching the successive transformations of 164,345 gallons of raw 

 juice as far as the third boiling ; and, considering the immense 

 number of measurements taken, the corrections for temperature 

 necessary, and the circumstance that a large number of observers had 

 to be employed, the results of my investigations are surprisingly 

 accurate. 



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