3. In other mills, the grinding power of each point increases with its distance from the centre; but in this mill, every point from the centre to the circumference has the same grinding power. A considerably smaller mill will, therefore, effect a given purpose, and the Eccentric Mill is therefore more portable than other mills.

4. The ever-changing action of the mill, and the quick discharge of the substance ground, prevent it from becoming heated, so that the Eccentric Mill may be profitably employed in grinding substances, which, in other mills, would be either spoiled or deteriorated in quality-or, by their melting, be impossible to be ground. If other mills were driven with that speed which can be safely applied to the Eccentric Mill, they would be made red hot in a few minutes.

These mills have been successfully introduced for the following purposes:

Hulling Rice, Coffee and Olives.

Grinding Grain of all kinds; Paints of all kinds, in water or in oil; Iron, Zinc, Copper, and Gold Ores, Plumbago and Manganese, Bones for Manure, and Bones for refining Sugar, Flint and Quartz, Charcoal, Plaster, Putty, Printer's Inks, Drugs and Dye Stuffs, Snuffs, Mustard, Coffee, Spices, Loaf Sugar, Starch, Gums, Resins, Asphaltum, India Rubber, Flax Seed, and Oil Cake, &c., &c.

Of the substances enumerated, some cannot be ground at all by other mills; in short, the Eccentric Mills are more economical in the power required to drive them, and in the labor of tending them; they are less costly for the work they do, and more portable; they are capable of being applied to purposes for which other mills are useless; and the wear and tear is trifling.

The annexed engraving (plates III and IV) are representations of the mill for grinding dry substances. The directions for using them are as follows:

The mill should run to the right, and make not less than three hundred revolutions per minute. Nearly any quantity can be ground by increasing the speed. The mill is regulated to grind fine and coarse, by the under-screw, on which the end of the shaft revolves; turning the screw to the left, will bring the plates together and cause the mill to grind finer. The regulating screw is held firmly in any position, by a small screw placed against its side. There are three reservoirs, which should be well supplied with oil. The first is on the top of the upper plate, two or three table-spoon fulls of oil should be poured into this reservoir through a small hole made in the top of the mill for that purpose. The second reservoir is the box, through which the main shaft passes; this is just under the spout of the mill. This reservoir should be filled with tallow so that it may supply itself. There is also a small hole in the back part of the mill, through which oil can be poured into this réservoir, if requisite. The third reservoir is the step in which the main shaft revolves, that may be filled with oil. The feeding is regulated by a shoe, acting against the tube of the upper plate, which causes the shoe to vibrate; this, with the slide in the hopper, regulates the quantity fed into the mill. Screw holes are made round the rim of the hopper, for the purpose of extending