(1) Can be made with shellac powdered fine, and a small portion of rosin, a piece about the size of a walnut to 1 oz. shellac, and a piece of old vulcanized indiarubber about the same size, which gives it toughness. Shellac about 1 oz. to 1 lb. of emery, well melt, and stir about in a small frying-pan; well mix the powders before applying heat. Be careful not to burn it, or get grease in it; have a ring of iron and a piece of plate iron prepared with black-lead and beer pretty thick; place the ring upon the plate and make a mould, turn the stuff into it, and well ram down evenly; put on one side to cool; when cold, turn out and chuck in lathe, and with a piece of red-hot iron bore a hole for spindle; after spindled put between centres, and trice-up with hot iron. Very good grindstones may be made with silver-sand mixed with powdered glass, and it is necessary to have some body besides shellac for coarse emery to form a body to bed the grains in. Emery dust from grinding glass, and Turkey stone slips, and slate, may be used as a substitute for the flour.

(2) The best emery wheels are formed of clean emery compounded with just enough boiled linseed-oil, the mixture being agitated for a sufficient period under exposure to a considerable heat and free access of atmospheric air, or some still more powerful oxidizing agent; it assumes the necessary degree of tenacity, and whilst warm, being exposed to hydraulic pressure in a suitable mould, and subsequent drying in a stove, the emery wheel is complete.