Adjoining this part of the Works was the Sulphur Refinery, where this material was prepared from the crude stock, and made ready for the incorporating process. About one hundred and thirty tons of very impure sulphur had been received from Louisiana, for the use of the Powder Works; it had been purchased before the war by the planters for use in the making of sugar, and was bought up by the Confederate officers. The best quality of gunpowder has its sulphur chemically pure, which could be demonstrated by showing no trace of acid when powdered and boiled in water, and should entirely evaporate on a piece of glass when heated, leaving no stain. This can only be accomplished practically by distillation. The crude article was melted and poured into upright, thick wooden boxes five feet high and ten inches square at the bottom, tapering upwards; when cold the earthy matters would be found in the lower portion by subsidence, leaving about three feet apparently pure. This was broken off and placed into two kettles of suitable form and dimensions, having furnaces; the tops of these kettles were connected by a bent iron pipe to an enlarged portion, which was surrounded with water. On the application of heat the sulphur vaporized, and passing over through the pipe was condensed in the cooled portion, whence it trickled in a thick stream into a receiving vessel below; the first portions being rejected, the remainder was of a beautiful citron yellow when cold, and entirely pure. Unlike the refined saltpetre, the purified sulphur had to be pulverized and bolted like flour before being used. The former was done by two iron wheels of twelve inches face and five feet diameter, weighing six hundred pounds each, revolving on a bed circle of iron like the incorporating rollers; the later was accomplished by bolters, but when these were worn out and could not be replaced, for want of the silk cloth, which was not to be found in the South, necessity compelled me to devise a different, and as it proved, a superior method. The pulverized sulphur was placed in barrels or cylinders, with hollow axles, which were made to revolve slowly by machinery; there were ledges on the interior which caused the sulphur to be lifted and poured over as the cylinders revolved; a light current of air was blown through each, entering the hollow axle at one end, and passing out through the axle at the other end, which led into an adjoining room; there the impalpable sulphur dust was deposited, much finer than by the usual bolting process.