November i, 1884.] THE TROPICAL AGRICULTURIST 



413 



cornea part detached; arid if a well-ordered land and sugar 

 company could be framed <>u these or similar lines, the 

 moneyed man might reasonably hope to find profit in aid- 

 ing the readjustment of the mechanism for its new work. 

 The numerous little sugar estates that are in Jamaica 

 would naturally group around and co-operate with diffu- 

 sion works placed conveniently near them. On some of 

 these estates cattle .mills are still in use; on others, 

 where water or steam is the power employed, the ordin- 

 ary roller presses are wanting in capacity. For these small 

 properties to incur the expense of new or enlarged 

 machinery, in order to obtain better results in sugar 

 making would be economically less to their advantage than 

 to spend the money in improved and useful agricultural 

 instruments. As to raise the percentage of sugar in the 

 juice would be more for the common good than if they 

 were to increase the percentage of juice expressed. A suc- 

 cessful grower of canes might, by selling to the adjoining 

 diffusion works, lay his account to reap all the farming 

 profit, and by taking a prospective interest in the sugar 

 made, participate in the profit of manufacture also. 



As regards keeping the canes for later use, when cropped, 

 there are two things to be noted; the great liability of 

 the juice, as an aqueous solution of sugar, to ferment on 

 exposure to the air, and the influence of heat to turn it 

 sour. The tendency of ad vegetables upon reaching maturity 

 is to fade and spoil. Sound ripe canes, however, deteriorate 

 but little if the skin is unbroken and the sugar cells are 

 not ruptured. The juice is produced separately in each 

 joint, and the plant ripens from the bottom upwards. Cut 

 canes have been known to keep for days without harm, 

 and even with positive advantage the ripening of the top 

 joints continuing to form sugar. Fermentation is said only 

 to take place in a solution of sugar and water when suffici- 

 ently dilute, with less than four parts water to one part 

 sugar it takes place imperfectly, if at all. As, therefore, 

 the proportion of 18 sugar to 90 juice is just 1 to 4, the 

 natural drying up of the cut eanes should help to pre- 

 serve them. In these circumstances it might be possible, 

 if there was available space, to stack and keep the upper 

 part of the stalk, whilst using the lower part that has 

 ripened, and thus to lengthen out the time for working 

 in the sugar-house. The means employed to lower the 

 temperature and prevent the heating of hay in the rick, 

 would probably answer with the cane, and by facilitating 

 evaporation accelerate the reduction of the water in the 

 juice to a safe point. Were tin experiment successful, and 

 the practice of storing canes to come into use, sugar works 

 would be able to maintain a permanent gang of skilled 

 workmen, and to carry oa operations with a smaller outlay 

 for machinery. But the drier the canes became, the less 

 amenable they would be to pressure, and for the liberation 

 of the juice it might be needful to have recourse to a 

 solvent iike the water of diffusion or maceration. 



These processes, maceration and diffusion are the oppo: 

 sites of one another. Diffusion is applied to, and acts 

 upon, the close cell of the plant; maceration on the open 

 cell. And the advantage is with diffusion, which, applied 

 to the beet, has surpassed maceration in success. By crush- 

 ing the canes, the cell walls are burst open, and with the 

 admission of air to the juice. Eermentation begins. _ The 

 juice gets also mixed with bit; of broken fibre mucilage, 

 and other parts of the substance of the substance of the 

 cane, which are washed out with it in the act of macer- 

 ation. Impurities are left behind, or not meddled with in 

 the course of diffusion, as in slicing the canes a certain 

 number only of the cells are cut open. The cells appear 

 to act as clarifiers, the sugar passing through the cell wall, 

 to change places with the water outside, whilst the albu- 

 men remains inert. The diffusion process, as improved by 

 Julius Robert, dates from 1864-5, and was first applied to 

 the cane at the Aska works, in the year 1866. From tin- 

 reports of good success in the use of it by this company, 

 its introduction into Louisiana followed in 1873. Twenty 

 years before, in 1845, in Guadelope, attention had been 

 directed to a plan of putting sliced eanes, in baskets, into 

 copper vessels with water. But nowhere in the British 

 possessions, excepting at Aska, does there appear to have 

 been any endeavour made to prove the capabilities of the 

 system for working up our cane crops. In Louisiana. an 

 apparatus used before for beet was brought over from 

 Europe and set up ; on trial, however, it was found to he 



unfitted for manipulating sugar-cane, ami two new and 

 complete machines were constructed for use on separate 

 plantations. Upon one of them, where the common kettles 

 or open pans, used for making brown sugar were employed, 

 the diffusion juice failed to granulate so readily as the 

 juice from the mill. On the other plantation, where an 

 exact test was made between the mill, an ordinary three- 

 roller mill, and diffusion, a vacuum pan being in use the 

 result demonstrated a considerable gain by the diffusion 

 process. Disagreement, however, arose between the parties 

 concerned in the affair, which prevented further experi- 

 ments from taking place. The next year the two diffusion 

 machines wen- removed and setup on another plantation, 

 and canes were purchased for working. But the season 

 was most unfavourable, the canes did not ripen well, the 

 transport arrangements were bad, there was no pecuniary 

 benefit, and thus the enterprise failed. The apparatus was 

 worked two or three years after this by the people who 

 bought it, but only on a small scale, and finally they took 

 it down and re-erected the mill. With more judicious 

 management it is very possible the process might have been 

 made a success, as the gain in saccharine matter was great. 

 At Aska, also, the working of the diffusion process was 

 said not to have been continued, a sure sign it was no 

 success. But so far is this from being the fact, that the 

 process is still in successful practice, and has been yearly 

 for seventeen years. At the works they now cut up during 

 the season 1,000 tons of canes a week, and are so satisfied 

 with the results, that they have ordered out a complete 

 apparatus of the newest construction. 



In Germany, 12± cwt. of sugar beets were formerly 

 assessed to make 1 cwt. of crystallised or grain sugar, 

 equal to a yield of 8 per cent. But now, owing to im- 

 proved cultivation and mauufacuture, it is believed that 

 in good years, 1 cwt. of sugar is obtained from 11 cwt. 

 of roots, being a return of 9 per cent. In France, not 

 mori than 5| per cent of grain sugar is made from beets 

 containing 10 per cent of saccharine matter. About 2 

 per cent is procured in the form of molasses, and of what 

 remains, rather more than ; '3 per cent is given up in 

 the pulp to the farmers. The losses in manufacture will 

 account for the rest. In Demerara, 12 cwt. of canes with 

 an assumed extraction of 66J per cent of juice, make 1 

 per cent of grain sugar, equal to a yield of 8$ per cent. 

 In Jamaica, the exports, on an average ot the five years 

 before mentioned, with the sugar made by the small settlers, 

 which is mostly consumed on the island, show a production 

 of less than one ton of sugar per acre, or a yield of 5 

 per cent. But on many of the estates, it may be noted 

 a large proportion of rum is made, Jamaica rum fetching 

 more money than the rum of other places. In Martinique, 

 13 cwt. of canes, with an extraction of 65 per cent of 

 juice, arc taken to make 1 cwt. of sugar, giving a return 

 of 7 <;-' per cent. The yield, however, at one of °he usines, 

 as the works are called, with an extraction of 77 ill per 

 cent, is stated to have been ,y!>l per cent of grain sugar 

 In other words, llj cwt. of canes made 1 cwt. of sugar] 

 a result as good as it is perhaps exceptional to have 

 accomplished. The theoretic out-turn gives, nevertheless, 

 a greater yield. For instance, taking the sugar in the canes' 

 to be IS pei cent and the juice 90 pi i cent of their weight, 

 the amount of sugar in the juice is found to be 20 per 

 cent. Then 11$ x $, = 2£ cwt,, of which an extraction 

 of ,7:>l per cent is If cwt, And this, allowing for the 

 change of a fourth of the sugar into molassi -'. shows a 

 loss ot one-third of a cwt. in every cwt. manufactured. 

 No account is made of the juice abandoned in the megass 

 from inability to gel it, or the loss would appear con- 

 siderably more. Bui take the exponent 1 to ia as a 

 better index of the proportionate production of sugar to 

 cane in good mills. Then 13 x , 2 ° as before 2 do cwt.. 

 the full contents. And if 85 per cent of juice be ex- 

 tracted, we get 2-21 cwt. of sugar and molasses. A result 

 that is tantamount to a loss by the ordinary mode of 

 manufacture of cwt. per cwt. In such a case it becomes 

 a pertinent question, bow to avoid this loss. In practice 

 there must of course be some waste, and unripe and damaged 

 canes will also cause a destructii .. of sugar. Vet as it 

 is possible to gel the Bugar in the beet with a discount 

 of little more than 1 per cent, it cannot be thought 

 a thing impossible to obtain it from the cane without (he 

 forfeiture of as much almost as is made. And it is evident 



