diamond is cemented to a small block of wood, which is firmly fixed to the table, and a line is made with a sharp where the division is intended to take place, which is afterwards filled with diamond-powder and olive-oil: the sawing is then commenced, and if the stone be large, the labor of eight or ten months is sometimes required to complete the uperation. The saw is made of a fine wire of brass or iron, attached to the two ends of a piece of cane or whalebone, the teeth being formed by the particles of diamond-powder, which become imbedded in the wire, as soon as it is applied to the line. In large ill-shaped stones, sawing is practised to advantage, but this method. is not advisable, unless the part to be removed is valuable.
The Diamond being thus brought to the required form, the next object is to polish the facets. The polishing mill is an extremely simple machine, consisting of a circular horizon-
