Sulphur is a simple, combustible, solid, non-metallic, elementary body. It is found generally in great quantities in the neighbourhood of volcanoes. It is also obtainable from metallic ores, and readily fuzes. At 170° Fahrenheit it begins to evaporate; at 185° to 190° it melts; at 220° it is perfectly fluid; and at 600° it sublimes. Sulphur is purified simply by melting: that which is supplied to Waltham Abbey has been once refined, and the following is a description of the apparatus and method for purifying and rendering it fit as an ingredient in Gunpowder. A large iron pot is set about three feet off the ground, or about the height that an ordinary boiling copper is placed, having a furnace underneath. This pot has a movable lid, which is fixed into the top of the pot with clay, and in which lid is an iron conical plug that can be removed at pleasure. From the pot lead two pipes, one to a large circular dome, and another to an iron retort, rather below its level. The last-mentioned pipe has a casing, or jacket, round it, which can be filled with cold water. The communication of these pipes with the melting pot can be shut off or opened, as occasion requires, by a mechanical arrangement. About 5¹⁄₂ to 6 cwt. of the once-refined sulphur is broken up into small pieces, placed in the iron melting pot, and subjected to the action of the furnace. The plug in the lid, and the pipe leading to the dome are now left open, but the pipe to the retort closed. After from two to three hours a pale yellow vapour rises, when the plug is put in, and the vapour conducted into the dome, where it condenses in the form of an impalpable powder, commonly called flowers of sulphur. A small pipe leads from the bottom of the dome, on the opposite side, into water, to allow the escape of the air, and sulphuric acid is taken up by this water. In about one and a half to two hours after, the vapour becomes of a deep iodine colour, when the communication with the dome is shut, and the one to the retort opened; at the same time, cold water from a tank above is allowed to pass into the jacket we have before mentioned, surrounding this pipe. The vapour then which distils over is condensed in the pipe, and runs into the retort below in the form of a thick yellow fluid. When nearly all has distilled, which can be known by the jacket getting cold, the communication is again closed with the retort, and the fluid sulphur left an hour, to get sufficiently cool to ladle out into moulds, the furnace door and the communication with the dome at the same time are again thrown open, that the rest of the vapour may pass into the latter. The flowers of sulphur thus obtained are used for laboratory purposes, being unfit for the manufacture of Gunpowder, from the acid they contain, and the crystalline sulphur, after being allowed to cool in the moulds, is barrelled up and used as the third ingredient in Gunpowder. PULVERIZING THE INGREDIENTS. ~Grinding.~ ~Screening.~