Vol. X. No. 231. 



THE AGRICULTURAL NEWS. 



67 



economical in construction, as they enclose the greatest 

 area with the smallest provision of material, and where 

 it is necessary continually to remove produce from 

 one part of the building to another, as in places where 

 stock is fed, economy is effected in the shorter distance 

 which such produce has to be conveyed. In the West 

 Indies, round buildings have a particular advantage m 

 that they most readily resist high windsand hurricaui s. 



The subject maj' be extended alinust indefinitely, 

 among other matters that have a more obvious con- 

 nexion with it being economical methods of keejiing 

 manures; the constant provision of good drainage, 

 especially for increasing the available moisture in the 

 soil; the provision of wind-breaks* for making plants 

 grow better, preventing the falling of fruit, and con- 

 serving the soil moisture: and the utilization of waste 

 products from the estate. Though these and others 

 equally important cannot be dealt with here, it is hoped 

 that what ha.s been said may suggest useful lines of 

 thought in connexion with the practice of economy im 

 estates. 



SUGAR FROM SHREDDED CANE. 



Much interest has been evinced lately in the process by 

 which sugar-cane is shredded and dried, and exported from 

 its country of origin to factories where the sugar is extracted. 

 The results of the trials have been eagerly awaited, and it 

 may be said at present that success for the process appears 

 to be indicated. 



A statement to this effect occurs in tlie American Sugar 

 Indiistri/ and Beet Sugar Gaxatte for January 1911, which 

 quotes from the Madisou Journal (Wiscoiisui) for December 

 20, 1910. More information is given, however, in the Louis- 

 iana F/anter for .Tiiniiary 21. 1911, where an anonymous 

 article is presented, from which the following facts are taken. 



The experiments are described as constituting an attempt 

 to procure white sugar directly from the sugar-cane without 

 the use of bone-black filters. They have been carried out at 

 the factory of the United States Sugar Company at Jladi- 

 son (Wisconsin). As is well known, the shredded and dried 

 cane was prepared at Nipe Bay, Cuba; this was done by lirst 

 of all subjecting the cane to the acticm of two closely 

 placed sets of circular saws, on shafts revolving in o[ipy!-ite 

 directions, which cut the cane into shreds about the size of 

 a toothpick. The cane was then snnt on to a drying oven, 

 through which it was carried by travelling belts, remaining 

 there until all the moisture, except 6 or 7 per cent., was 

 removed. The dried cane finally passed over screens, which 

 separated the ' pith' from the ' fibre', the two products then 

 being baled separately. 



When the shredded cane arrived at the factory, two 

 kinds of attempts were made to deal with it. In the first, 

 the diffusion process was employed, but was found to be too 

 slow to be of practical use, apparently liecause the water 

 pressure in the cells packed the cane so tightly that circula- 

 tion could not take place. The remedy was tried of reveising 

 the direction of the water pressure, without success. In these 



*See Agricultural Neus, Vol. X, p. 1. 



trials, the pith alone was used: but as the fibre is less likely 

 to pack together and stop the flow of the diffusion water, it 

 is thought that the method may be employed successfully for 

 this, and trials are to be made. 



Great success is said to have been obtained with the sec- 

 ond method, in which the sugar was extracted fiom the dried 

 cane by means of centrifugals. The first part of the process 

 consisted in shredding the baled cane again by subjecting it 

 to the action of saws, on to which it was fed from an endless 

 moving platform. The effect was to tear the cane into 

 shreds, which were sucked up into a wide tube and fell into 

 a mixing vat: here the first cane is mixed with water, while 

 later, it is treated with the last water that has been used for 

 the exhausted cane. 



The next stage in the process was the extraction of the 

 sugar. For this, the mixture was fed into centrifugals where 

 the sugar is extracted with such speed that in less than two 

 minutes the amount in the pith is reduced from 55 or 60 per 

 cent, to '01 per cent, or less. The similar reduction for the 

 fibre takes place in about three minutes. A useful feature of 

 this method of treatment i.s that it leaves the residue of 

 megass dry enough to be packed for shipment to the paper 

 mill.s. 



The juice coming from the centrifugals has a dark brown 

 colour and is very dirty, testing between 11° and 14° Brix; 

 its purity should be about 89-3 per cent., but was found to 

 be actually 72'5 to 744 per cent. 



The first stage in the purification of the juice, which is 

 known as raw juice, is to mix it with 2 to 3 per cent, of 

 lime, added in the form of milk of lime of about 25° or 30* 

 Beaume. After the mixture has been subjected to the action 

 of carbon dioxide, the juice is pumped through filter presses 

 in which it loses the calcium carbonate that has been 

 formed, as well as a large proportion of the impurities. The 

 juice passing from the first filter possesses an alkalinity of 

 about 7 per cent., a purity of about 7I'l to 75'9 per cent., 

 while the Brix has been reduced to about 7° or 8". A second 

 carbonatation is now carried out, making the characteristics 

 of the juice as follows: alkalinity 2 to 0'3 per cent., purity 

 74'6 to 76'5, Brix between 6' and 7' (on account of the 

 addition of water containing sugar, from the filter presses), 

 colour light yellow. 



The juice is now sulphured, with the result that it is 

 bleached and its purity is increased, the alkalinity becoming 

 01 to '02 per cent and the purity 75 to 76'8. The final 

 result is to produce a juice having a Brix of 5° to 6'5°, in 

 which state it runs into the evaporators. 



In the evaporators, the density becomes about 60° Brix; 

 the juice from them is passed through thick juice filters and 

 sand filters of the kind used in beet sugar manufacture. It 

 has now the following qualities: purity 767 to 77'5 (esti- 

 mated at 95 per cent, for normal cane), and alkalinity less 

 than 002 per cent. Such juice produced a massecuite having 

 a light lirown colour, a Brix of about 92'8°, and a purity of 

 74'5 (estimated at 922 to 92'8 for normal cane). 



The sugar obtained in this way possessed a very light 

 canary-yellow colour; it was reboiled and formed a very white 

 sugar w hen separated from the mother licpior in the centrifu- 

 gals. It is a matter of importance that this sugar is hard, 

 with a high lustre and a grain suitable for marketing purposes. 



Future work will include the enlargement of the drying 

 plant at Xipe Bay, and the installation of continuous centrifu- 

 gals at Madison in the place of the sugar centrifug.ils that 

 have been used so far. In this way, the capacity of the plant 

 will become 100 tons of dried, or 300 tons of standing, cane 

 per day of twenty-four hours. The first actual manufacturing 

 season will commence at some time during this month. 



