4.  “To drain and dry the sugar perfectly, and to save all the molasses.”

The advantages to be anticipated from these improvements, superadded to an improvement in cultivation, cannot be estimated at less, upon a moderate calculation, than from 150 to 200 per cent. of increase in the production of sugar, with hardly an appreciable increase of labor or expense; for we have, in the first place, a gain by improved culture of, at least, two hogsheads an acre in sugar, equivalent to 100 per cent.; in the next, by employing improved mills and extracting the residuum, 30 per cent.; by conducting the process of manufacture more judiciously, 10 per cent.; and by the prevention of waste during the transit to market, 10 per cent., making a total of at least 150 per cent.

The common sugar-mill consists of three cylinders, tightened either by wedges, if in a wooden frame, or by screws in a cast-iron frame.  If in an iron frame, the above-mentioned noise is obviated, but the friction and loss of power is the same, which is ascertainable by subsequent investigation.  The cylinders or rollers, which are moving either horizontally or vertically, are from eighteen to twenty-four inches in diameter, with bearings or shafts of one fourth of their diameter.  If the bearings or shafts of the cylinders were of less substance, they could not resist the great strain to which they are subjected when in operation.  The whole of the prime mover (steam-engine, water-wheel, or animals), minus the friction of intermediate machinery, is transmitted to the plains of these rollers and resisted by their bearings; hence the action is equal to a weight moving on low wheels of eighteen or twenty-four inches in diameter, on axles of from four to six inches thickness, which weight is equal to the force applied; consequently, if the strain is greater than the resistance of the rollers or the bearings, they must be wrenched off, or if greater than the force applied, the mill will be stopped.  The power necessary to move weights upon wheels, on a smooth and level surface, is in proportion to the respective diameters of wheels and axles.  The same pull which moves one ton at a given velocity upon a wheel of two feet, with an axle of six inches, will move four tons, if on a wheel of four feet diameter, with an axle of six inches.  Consequently, cylinders of small diameter, with strong and substantial bearings, are only admissible as working machines, if no other mechanical means are applicable, as, for instance, in rolling out metals, compressing the surface of various bodies for a glossy appearance, or, generally speaking, to produce a certain and equal form of the substance which is pressed and passed between them.  They compress the atoms of bodies, and for this reason alone are ill suited to separate the fibres of the sugar canes, and to express effectively the saccharine matter between them.  A practical proof of this demonstration is furnished by every sugar cane which has gone through the mill.  Fresh megass is at present better suited for fattening animals than for fuel under the sugar pans.