Arizona weekly enterprise., 1888-01-21
THE MANUFACTURE OF euNpowDEa
Preparing the Saltpeter-Production of Sulphur and Charcoal-NIixing Process.

Lno of Sulphur and Charcoal-Mi1ing Process.
 Gunpowder is composed of three ma- berials-sulphur, saltpeter and charcoal, But tossing these materials together any way does not make gunpowder by any means. There is a method, and it is somewhat complicated. That pursued at the Waltham works, the most famous in the world, is as follows: The saltpeter comes chiefly from Bengal and other provinces in India, where it is found mixed with the soil and as an incrusta- ton on the ground. It is boiled, and crystallized by evaporation. Before 1t is used at the factory it is purified by process which acts on the principle that hot water will receive in the solution more of the saltpeter than the impurities mixed with it. So the saltpeter is boiled tn water, the resulting solution filtered and cooled in large yats, at the bottom of which the pure saltpeter is deposited in fine crystals. It is then washed, dried and stored in bins, care being taken that no sand or gritty particles are introduced, as under pressure they might produce an explosion.
 The same precautions are taken with regard to the production of the sulphur and charcoal. The best sulphur comes from Sicily. It is purified by a distilling process, which brings it out in handsome yellow crystals. Then it is pulverized by being ground under iron runners, and sifted in kind of revolving cylindrical sieve called a slope reel" The charcoal is made of wood from Holland and Ger many. Alder and willow are planted near the factories, and the charcoal from these Is used for common powder, and black dogwood for fine rife powder. The charcoal is not prepared in pits, but the wood is sawed into short lengths and packed into iron cylinders, called slips, which are placed on a small carriage and run into retort like that used in gas works. Here the slips are exposed to the flames for a period of two and half or three and half hours, the gas issuing from the wood being utilized for fuel. The charcoal when taken out is ground in machine like giant coffee-mill, and then sifted like the sulphur.
 The next process is mixing the ingredi- ents. The proportions vary in different countries. For English government pow der of every kind it is saltpeter, seventy five parts; sulphur, ten; charcoal, fifteen the sulphur being reduced almost to a minimum, as its chief use is to ignite the charge and hasten its motion. The ingredients being weighed for a charge of fifty pounds, are poured into "churn," which is revolving drum placed horizontally, and having within it an axis revolving in different direction from the drum, and furnished with eight rows of projecting arms. So rapid is the action of this machine that three minutes is sufficient to thoroughly mix the ingredients. IL is then called the green charge" and is ready for the in cooperating mills, where the object is tt make the mixture so intimate that new substance is created, namely, gunpowder
 The incorporating houses of Walthan have thirty-two separate mills. Eact mill consists of pair of runners coupled together by a strong axle. This axle rests in the socket of an upright shaft which, passing down through the mill bed, is connected by bevel wheels with a revolving horizontal shaft driven by steam or water-power. The runners are of Derbyshire limestone and iron,. and weigh from three and one-half to four tons. The size of the iron ones is from three and a half to seven feet in diameter The n1ill-bed-a circular vat with a flat bottom and sloping sides-is of stone ol metal. On this bed fifty pounds of the green charge is spread and moistenec with water, and the mill is set going Com1non powder is left under the mil three hours, rife powder five hours.
 On leaving the mill the gunpowder i in the form of soft cake which easil, breaks up into dust. This is pressed il layers between plates of copper or gun metal to increase its hardness or density and then made into the required form by machinery. Cincinnati Enquirer.