608 



SUGAR-CANE 



SUGAR-CANE 



the mill in wooden flumes carrying a stream several 

 inches deep, the distant flumes being V-shaped and 

 of two boards, the mill flumes larger and of three 

 boards. 



Machine loaders are coming into use for trans- 

 ferring the bundles of cane from the primary car- 

 riers to those on the permanent ways. Chains or 

 wire cords of the requisite length are provided, 

 and these are fastened about the bundles of cane 

 as they are assembled on the primary carriers. 

 When these latter reach the permanent-way car- 

 riers, mechanical loaders attach their tackle to the 

 bundles and lift them to the trucks, trolleys, or 

 punts, as the case may be. These loaders are usu- 

 ally portable derricks. Where plantation railways 

 are in use, they often have portable derricks 

 attached to trucks. These are run on to sidings 

 and from thence the trucks of the main train are 

 loaded in succession. Naturally, all the mechanical 

 contrivances are in use just in proportion to the 

 price of eflicient labor. Where labor is high they 

 are in more common use than where it is cheap. 

 In some countries that produce much sugar the 

 modern labor-saving machines and implements are 

 almost unknown. That they will be further per- 

 fected and come into wider use is certain. 



There are more patterns of unloaders than of 

 loaders, as might be expected from the fact that the 

 problem is simpler. One of the commonest unloaders 

 is a series of sprocket chains arranged on a frame 

 and carrying at intervals perpendicular steel fingers 

 a foot in length. The moving chains are lowered 

 over the truck of cane and the motion of the steel 

 fingers slides the cane off on to the mill carriers. 

 As these fingers can be raised or lowered at will, 

 the cane can be unloaded to accommodate the speed 

 of the crushers. Another unloader consists of a fif- 

 teen-foot mechanical finger with a universal move- 

 ment. The end is forked and hooked downward, 

 so that the cane can be raked oit the truck on to 

 the mill carrier. 



Manufacture of cane-sugar. 



To produce sugar from sugar-cane it is necessary 

 to extract the juice, purify it, and then evaporate 



Fig. 835. Sugar-cane loading-derrick in action. 



it until the sugar will crystallize. Formerly these 

 operations were conducted with very simple 

 apparatus, and even now such crude methods are 

 in use in the less progressive countries. The most 



primitive wooden or stone rollers driven by direct 

 animal power, will express much. of the juice from 

 good ripe cane, and it may be concentrated without 

 purification in simple open pans. The result is a 

 poor sugar, much molasses, and the extraction of 

 only a part of the sugar, much of it remaining in 

 the bagasse and going to waste. The most perfect 



Fig. 836. Loading cane into cars. 



Hawaii. 



mills are only improvements of this simple process. 

 The use of more powerful rollers was the first 

 improvement; then came the multiplication of the 

 rollers, not only because the repeated pressings 

 would remove more juice from the already pressed 

 fiber, but because between the crushings the fiber 

 could be treated with hot liquids, that on being 

 removed by the next set of rollers left the su- 

 crose in a more dilute solution in the bagasse. 

 The amount of moisture that is left in the ba- 

 gasse is determined by the pressure; the amount 

 of sugar is determined, however, by the con- 

 centration of the solution of sucrose in that 

 moisture. 



Shredding and crushing. — Endless carriers, 

 several feet wide, receive the stalks and elevate 

 them twelve to fifteen feet and dump them into a 

 shredding machine or its equivalent. Here the 

 cane-stalks are torn into fragments by revolving 

 cylinders that somewhat resemble a peg-drum 

 threshing machine in their action. The cane frag- 

 ments pass without further alteration to the first 

 set of rollers. These three corrugated steel rollers 

 are set to press out about three-fourths of the 

 sucrose, an operation easily possible with the best 

 mills. The fiber or bagasse from these rollers is 

 macerated during about two minutes, as it passes 

 on carriers to the second rollers, the macerating 

 liquid being the heated juice from the final set 

 of rollers used at about 150° Pahr., and sprayed 

 at the rate of about six cubic feet per minute. 

 About 10 per cent more of the sucrose is pressed 

 from the macerated bagasse as it passes through 

 the second set of rollers, which are like the first in 

 action. These operations are repeated between the 

 second and third sets of rollers, except that the 

 macerating liquid is hot water in this case. The 

 third rollers extract another 3 to 4 per cent of 

 sucrose. 



The bagasse from the third rollers is carried to 

 the furnaces and is mechanically dumped into 

 them at a rate that can be regulated, so that the 



