It is most certain, that, if powder be kept long in a damp place, it will become weak and moist, and great part of it will be formed into hard lumps, which is a certain sign of its being damaged. When powder is thus found, you will also see at the bottom of the barrel some saltpetre, which, by being wet, will separate from the sulphur and coal, and always fall to the bottom of the vessel wherein the powder is contained, and settle there in the form of a white downey matter; but the only method to prevent this, is to move the barrels as often as convenient, and place them on their opposite sides or ends, to which they before stood: but although ever so great care be taken of powder, and it be kept as dry as possible, length of time will greatly lessen its primitive strength. Therefore when any of the above mentioned accidents happen to your powder, you may recover it by applying to the directions here given; for example, if you imagine that the powder has not received much damage, proceed thus. Spread it on canvas, or dry boards, and expose it to the sun, then add to it an equal quantity of good powder, and mix them well together, and, when thoroughly dry, barrel it up, and put it in a dry and proper place. But if gun-powder be quite bad, the method to restore it is as follows; first, you must know what it weighed when good; then, by weighing it again, you will find how much it has lost by the separation and evaporation of the saltpetre; then add to it as much refined saltpetre, as it has lost in weight, but as a large quantity of this would be difficult to mix, it will be best to put a proportion of nitre, to every twenty pound of powder; when done, put one of these proportions into your mealing table, and grind it therein, till you have brought it to an impalpable powder, and then searce it with a fine sieve; but if any remain in the sieve that will not pass through, return it to the table, and grind it again, till you have made it all fine enough to go through the sieve; being thus well ground and sifted, it must be made into grains in the following manner, first you must have some (copper wire sieves) made according to what size you intend the grains should be; these are called corning sieves or grainers, which being provided, fill them with the powder composition, then shake them about, and the powder will pass through the sieve formed into grains. Having thus corned your powder, set it to dry in the sun; and when quite dry, searce it with a fine hair sieve in order to separate the dust from the grains. This dust may be worked up again with another mixture; so that none of the powder will be wasted: but sometimes it may so happen, that the weight of the powder when good cannot be known; in which case add to each pound an ounce or an ounce and a half of saltpetre, according as the powder is decayed, and then grind, sift, and granulate it as before directed.