Sulphur is prepared by heating a quantity of crude sulphur in an iron pot, conducting the vapors into cool chambers, where they fall as a very fine powder, called flowers of sulphur. When the chamber becomes warm these flowers of sulphur melt, and run into cylindrical moulds, in which form the sulphur is called roll sulphur, and is quite pure. It is then ground and passed through a very fine sieve, when it also stands ready.

The last and most important ingredient is Nitre or, as it is more commonly called, saltpetre. This is obtained chiefly from Bengal, and in its crude or "grough" state contains from one to twenty per cent. of impurities; common salt being the chief. In this state then it arrives, and before being used has to be freed from every impurity. This used to be done by repeated boilings and crystallizations; but now it is boiled once and passed (in a fluid state) into large shallow copper pans, called coolers. Now if allowed to cool at rest it forms itself into large crystals, which contain much that is impure; but if you can get the crystals small, there is little impurity to be found. This is obtained by keeping the liquid constantly in motion during the cooling process; so that the nitre crystallizes in very small particles, so small indeed that the saltpetre thus crystallized is called saltpetre flour, and is, if carefully washed with distilled water, absolutely pure, and so fine that no grinding is necessary. Under the old system the saltpetre had to be thrice boiled, thrice set to cool in crystallizing pans, and then me]ted, run into moulds, cooled, and ground. We are indebted to the French for the new process.

After having then seen our ingredients carefully prepared, we now bring them together in a house, called the mixing house. They are here weighed in the following proportions:ó

These ingredients are then placed in the mixing machine, which is simply a wooden box, through which a shaft passes armed with long copper or gun-metal teeth. The shaft is made to turn on its axis very rapidly, and by means of the teeth the mass is intimately mixed. A bag is placed under the machine, a slide is withdrawn from the bottom, and the powder (for such it is now, but very weak) falls into the bag. The quantity placed in one bag is called a charge, and weighs between forty and fifty pounds. The charge ( green charge called generally) is now ready for the incorporating mills, where the several ingredients, which before were only mixed, are now incorporated, or very intimately combined, by means of a heavy grinding pressure. Imagine a large round dish of iron. In the centre of the dish is an upright shaft, made to turn by means of gearwork underneath the floor; on this dish are placed two wheels, called runners, made of iron or stone, each weighing three or four tons. Through the centre of each runner a horizontal spindle passes, which spindle also passes through the upright shaft before mentioned, cutting it at right angles. When the upright shaft is put in motion of course it carries round these runners, which perform about ten revolutions per minute. The weight of the runners causes great pressure upon the powder, which is spread equally over the bottom of the dish, and the small circle in which the runners revolve causes the grinding, by which means, and the aid of water, the intimate mechanical combination of the ingredients, upon which the strength of the powder entirely depends, is obtained. The time necessary to bring the powder to its proper strength varies from one hour to ten, according to the quality required. One manufacturer has patented a process by which he causes the bottom of the dish to be heated, by which means he obtains the required strength in a much shorter time. When taken from these mills it is in broken cakes of a grayish color, and about half an inch in thickness. It is now called mill-cake, and has attained its greatest strengthóall after processes decreasing its explosive force, but increasing its durability.

From the incorporating mills it is taken to the press house, where the mill-cake is passed between cylindrical toothed rollers, which in motion turn towards each other, and crush the powder again to dust. On one side of this press house you see a large cubical box placed between four iron columns, which support a huge crossbar of iron, called a cap; underneath the cap is suspended a cube of wood to fit the box which stands below. The powder, when broken down, is carried to this box, on the bottom of which a layer of it is placed. This layer of powder is covered with a sheet of copper, and on the copper is placed another layer of powder, then another sheet of copper, and so on, alternately a layer of powder and a sheet of copper, until the box is full. A man then turns a small cock, the box begins to rise, and pushes itself against the piece of wood suspended beneath the cap. As this wood fits the box, the box keeps rising, but as it rises the powder is compressed to the requisite hardness. But how is the box made to rise ? By hydraulic pressure. The box stands upon the ram, as it is called; this ram fits into an iron cylinder; into the cylinder water is forced, which raises the ram and of course the box placed upon it. The pressure obtained is generally about four tons to the square inch upon the ram. When the pressure is taken off, and the box opened, the powder and copper are compressed into one solid mass; but a few hard blows with a wooden mallet soon cause the cakes to separate. The copper plates are put aside for future use; the cakes of powder, about two feet six inches square and one-eighth of an inch in thickness, are carried to the breaking-down machine, where they are again passed between the toothed rollers and broken into pieces hard and black, of irregular forms, varying from an inch and a half to half an inch in length. The powder is now fit for granulating or corning, as it is called. Before we leave this house we may just get a glimpse at the men here, and yet the men you cannot see, only their intensely black faces and lively eyes. Strong men and true, no doubt, to their employers, but not always conscious that while careful for " the master, " they are caring for their own lives.

We take leave of the press house, then, and follow the hard pieces of powder to the granulating house. Here we are in great danger, and not very well able to see it on account of the "dust" flying about. However, we can perceive the " house" is tolerably full of machinery; consisting principally of the toothed cylindrical rolls and " Jacob's Ladders." These " Jacobs " are endless straps passing over wooden wheels; each strap has a number of cups fixed upon it. The powder is " shot" into a hopper on the floor; at the bottom of this hopper one of the wooden wheels rotates, and over it the endless strap passes. In the downward journey the cup is inverted, but no sooner does it get its turn on the bottom wheel that it rights itself, and not only so, but fills itself with powder, which it carefully carries to the housetop, and as it turns on the upper wheel shoots its load headforemost into another hopper, from which it passes between the rollers, and is crushed into the required sized grain. So these " Jacobs" save the trouble and expense of having men to carry up the powder on their backs. The powder here is not only granulated, but a large portion of the dust is taken from it and returned to the incorporating mills.

We have now the powder in grains of various sizes and of a very dull grayish brown color, not much like the powder of commerce. But we shall get it so much like that, that you will recognize it wherever you may meet with it. From the granulating house it is carried to the rubbing house, where the powder is placed in cylindrical vessels of wood or canvas, and rapidly turned upon the vessels' axes. By this motion the grains of powder are hardened, and by the attrition they gain a glossy appearance and look bluish-black. This rubbing of the powder is a great deterioration to the explosive quality of the powder; it makes it less angular, but, as a counterbalance, it is much more durable, being less impervious to moisture than before. Well, having whirled it in the cylinders for ten or twelve hours, and having seen it brought out, and noted its different appearance, we follow it to the drying house. Not long since it used to be dried as follows: The powder was spread upon canvas cases and placed in racks round a room, called the stone; into the wall of this building a huge iron pot was built: not standing on its bottom, but so placed that the bottom of the pot should project into the room while the mouth was outside. In this a fire was kindled, and the bottom of the pot heated to a red heat. Pleasant, certainly, when one entered to see the round red pot glaring in amongst the powder and threatening death and destruction to all. Now the stove is heated by means of steam pipes passing through it, and the temperature usually obtained is about 130. For twenty hours it rests in this warm climate, during which time it parts with all its moisture except about nine per cent. At this stage the powder is somewhat dusty and of different-sized grains; two things then are required, to clean it from the dust, and to separate the grains into the various sizes, for large or small arms. To accomplish these ends, the powder is transported from the stove to the dusting house.

The dusting house, as its name implies, is the place where the powder is dusted, or finally cleansed from any remaining dust. This is an important affair, as the fouling or not fouling of the gun depends greatly upon this matter. It is generally performed by causing the powder to run through a series of reels covered with open canvas, which reels are rapidly whirled round, and while they are in motion all the very fine powder or dust falls through the canvas. When properly dusted, the different-sized grains have to be separated one from another; the " large grain " for artillery; the " fine grain " for rifles; the " double F." and " treble F." for sporting purposes; and so on. When separated it is carefully weighed, put into barrels, headed up, and carried away to magazines, quite finished and ready for use.

These various processes cannot be carried on without much risk to life and property, hence the necessity that exists for the greatest possible care throughout all departments. Every man has clothes to be used only in the houses, so that there can be no chance of the least particle of grit getting on to the clothes, neither is any man permitted to wear metal buttons. All shoes are exchanged for shoes made only of leather, no nails of any kind; and these are worn only in the houses. In the machinery brass and copper are largely employed, because from them it is almost impossible to strike fire and to prevent any friction under foot should grit get into the houses, the floors are carefully covered with leather. Still, with all these precautions, accidents are not entirely avoided, though greatly diminished.