Harvesting.— Cane has about eight months to produce sugar in this country, while in Hawaii, Cuba and other tropical countries its growth may extend over one year or 18 months before being harvested. The harvesting period in this country is from October to January, in those, from January to mid-summer. Cane is usually cut by hand, though cane-cutting ma chines have been in operation of recent years, These, however, have not been perfectly satis factory. The instrument used for cutting cane is a large steel knife, with a blade about five inches wide, 18 long and provided with a lit tle hook on the back. The cane is cut at or near the surface of the ground, the leaves stripped off with the hook, the top cut off at the last matured joint and the cane put into piles along the rows. From here it is taken up, either by hand or machinery, put into carts and laid across large ropes, or put into cars, and transported to the factory. Here the cane is taken out by hand or machinery and if the latter, it is accomplished by a derrick which lifts the entire load by means of the rope on which the cane has been laid. These large bundles are piled up around the factory and when the cane is to be crushed, it is taken un by the same machine, elevated to an incline, dropped on it and slides down to the cane carrier and thence to the mill.
Extraction.— There are in practice two methods of extracting the sugar from cane. namely, milling and diffusion. The older and more generally used is milling, the diffusion being confined almost entirely to manufacture of sugar from beets. A mill may consist of two or three rollers, usually placed horizontally, and vary in length from 18 inches to 72 inches. and in diameter from 12 to 32 inches. If the mill is to be operated by oxen or by horses the rollers are set in an upright position. The most primitive mill was the wooden roller. This has been used in a small way in some of the Southern States since the Civil War, but there is at this writing, perhaps, not one in existence in this country. In most large factories there are two of these three-roller mills and in some, three. The rollers are so arranged that two are placed on a level and geared to move in the same direction while the third moves in the opposite direction. If a factory operates two mills the rollers of the first are further apart than those of the second, and if three mills, the third has its rollers closer together than the second. These rollers revolve very slowly (one and one-half to two and one-half revolu tions per minute) and are operated under great hydraulic pressure. To relieve the strain upon the mill, a cane crusher or shredder has come into general use. The cane enters one of these as it leaves the cane carrier and is either crushed or shredded into small pieces before reaching the mill. This not only relieves the mill of the work of crushing the whole cane, but increases its capacity. The capacity of
mills will vary from 200 to 1,400 tons of cane per day and the extraction is 70 to 80 per cent on the weight of cane and 90 to 95 per cent of the sugar in the cane. Between the first and second mill the juice receives a spray, through a perforated pipe, of either hot or cold water, the object being to dilute the sugar so a larger percentage will be crushed out by the second mill. This addition of water is termed maceration and the quantity of water added may vary from 5 to 15 per cent of the weight of the cane and in some cases as much as 20 per cent, the quantity depending somewhat upon the value of fuel and the capacity of the evaporating outfit. In some instances the di luted juice from the third mill is returned and used for macerating the crushed cane between the first and second mill, and water is used between the second and third. The value of maceration may be seen from the following estimate taken from practice: It has been esti mated that maceration increases the extraction from four to six pounds of sugar per ton of cane. A factory crushing 500 tons daily and operating for 90 days, would crush a total of 45,000 tons. An increase of five pounds per ton would yield to this factory 225,000 pounds of sugar. This quantity at 3.5 cents per pound (the price paid for 96 test last season in Louisiana) would amount to $7,825. Supposing that 10 per cent of water on weight of cane was used, then for every ton of cane there would have been 200 pounds of water or approximately 25 gal lons. It is estimated that one pound of coal will evaporate about eight pounds or one gal lon of water. Then the 25 gallons of water would require 25 pounds of coal. Coal being valued at $4 per ton or 20 cents per 100 pounds, 25 pounds would be worth five cents, this dr ducted from 17.5 cents, the value of five pounds of sugar, leaves 12.5 cents as the net value gained per ton of cane and the 45,000 tons wculd be worth $5,625.
Diffusion.— Extraction by diffusion is treated under beet sugar and it is necessary here to give only a brief statement with reference to diffusion as applied to sugarcane. Diffusion has been practised at several factories in Louisiana and some other countries, but it has not yet met with very great favor. The diffusion proc ess in Louisiana has been abandoned. There are claimed for diffusion the advantages of a purer juice and a higher percentage of extraction. In a battery used for sugarcane, the juice will vary in sucrose from .3 per cent in the last of a series of 12 to 14 cells, to 16 per cent in one freshly filled. The disadvan tages of this process are, large amount of water to evaporate, more skilled workmen required and the chips are not so good fuel even after running through a press, which causes ad ditional expense.