A bushel of rice will weigh about sixty or sixty-six pounds, and an acre of middling land will produce twenty-five bushels.

Various machines have been contrived for cleaning rice, of which one secured by patent to Mr. M. Wilson, in 1826, and thus described by Dr. Ure, may be regarded as a fair specimen:—­It consists of an oblong hollow cylinder, laid in an inclined position, having a great many teeth stuck in its internal surface, and a central shaft, also furnished with teeth.  By the rapid revolution of the shaft, its teeth are carried across the intervals of those of the cylinder, with the effect of parting the grains of rice, and detaching whatever husks or impurities may adhere to them.  A hopper is set above to receive the rice, and conduct it down into the clean cylinder.  About eighty teeth are supposed to be set in the cylinder, projecting so as to reach very nearly the central shaft, in which there is a corresponding number of teeth, that pass freely between the former.

The cylinder may also be placed upright, or horizontal if preferred, and mounted in any convenient framework.  The central shaft should be put in rapid rotation, while the cylinder receives a slow motion in the opposite direction.  The rice, as cleaned by that action, is discharged at the lower end of the cylinder, where it falls into a shute, and is conducted to the ground.  The machine may be driven by hand, or by any other convenient motive power.[43] The growth of rice in North America is almost wholly confined to two States; nine-tenths of the whole product, indeed, being raised in the States of South Carolina and Georgia.  A little is grown in North Carolina, Louisiana, and Mississippi.

The aggregate crop, for 1843, amounted to 89,879,185 lbs., while in 1847 it had risen to 103,000,000 lbs.

Besides the rice which is raised in the water, there is also the dry, or mountain rice, which is raised in some parts of Europe on the sides of the hills.  It is said to thrive well in Cochin China, in dry light soils, not requiring more moisture than the usual rains or dews supply.  By long culture the German rice, raised by the aid of water, is stated to have acquired a remarkable degree of hardness and adaptation to the climate.  The upland rice of the United States is thought by some to be only a modified description of the swamp rice.  It will grow on high and poor land, and produce more than Indian corn on the same land would do, even fifteen bushels, when the corn is but seven bushels.  The swamp rice was originally cultivated on high land, and is not so now, because it is more productive in the swamp, in the proportion, as is said, of twenty to sixty bushels per acre; and the use of water likewise, it is stated, makes it easier of cultivation, by enabling the planter to kill the grasses.  It is thought that on rich high land, rice may be made to produce twenty-five or thirty bushels to an acre in a good season.  A letter from a gentleman in North Carolina gives the following account of some rice raised there.  He says:—­