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in eight hours they use to moisten the Powder with "a little fair water; others who are more curious, "put water something thickned with quick-lime; c "thers use White-wine Vinegar; others Aqua vitæ : "But if it be not moistned with something once in "eight hours, the Powder will grow dry, and in half " an hour after it will take fire. As soon as the Pow"der grows dry, you may find it, though at a di"stance, by the noise of the Mill; for then the Pestles "will rebound from the bottom of the Trough and "make a double stroak. The only danger to the "Mill is not from the Trough; for many times the "iron Gudgeons grow hot for want of greasing, and "then the dust that flies about will be apt to fire, and "fo the Mill blows up.

"From the Mill the Powder is brought to the "Corning-house, of a middle temper between moist · "and dry. The way of corning it is with two hair "Sieves joyn'd together, the upper Sieve inclosing "fome part of the hoop of the lower Sieve: The

upper Sieve hath holes of the size you will have "the Powder grained at; the holes of the lower "Sieve are much lesser: The upper Sieve they call "their corning Sieve, the lower their wet Dust"er: They lay the Powder upon the upper Sieve "fome two inches thick; upon that a piece of heavy "wood made like a Trencher, of about eight inches " diameter and two and a half in thickness, called a "Runner, which when the Sieve is moved, by its "weight and motion forces the Powder thorow the CC upper Sieve, and that corns it. Then the lower Sieve receives the Powder, and lets the dust g thorow into a Bin, over which the Sieve is shaken "called the Dusting-Bin.

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"Wher

"When the Powder is thus corned, it is laid about "an inch and half thick on the drying Sieves, "which are made of course Canvase fastned to slight "frames of Deal about an ell long and some twenty "inches broad; and thus it is carried into Stoves to "dry.

"The Stove is commonly a little Room about "eighteen or twenty foot square,with ranges of small

Firr poles about two foot one above another, to lay "the drying Sieves upon, but only on that side the "fire is made. Besides a glass window to give light, "there must be a small lover hole at the top of the "Room, to let out the steam,else the Powder will not "only be the longer a drying,but often by the return "of the steam on the Sieves, the top of the Powder "will be so crusted that the lower part will not dry. "The Rome is heated by an Iron of about a yard high "and half a yard broad, cast in the form of an Arch equal to a Semy-quadrant, and placed in the back "of a Chimney, the fore part whereof is like a Furnace; and to avoid danger, opens into another lit tle Room apart called the Stoke-hole.

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"The Powder is brought into the Stove before it "be heated, and is not taken out again till the Stove "be cold; and about eight hours is required to the "drying of it. In hot Countries the Sun is the best "Stove, and a great deal of danger and charges that way avoided.

"After the Powder is dried, it is brought again to "the Corning-house, where it is again sifted over "the dusting Bin in other double Sieves, but without

any Runners. These Sieves have both of them "fmaller holes than the former: The upper Sieve is "called the Separater, and serves to divide the great

corns

corns from the lesser; the great corns are put by "themselves, and serve for Cannon Powder: The "lower Sieve is called the dry Duster, and retains "the small corns (which serve for Musquet and Pistol) "and lets fall the dust into the bin, which is to be "mingled with fresh Materials, and again wrought "over in the Mill.

"So that good Powder differs from bad (besides "the well working and mingling of the Materials) "in having more Peter and less Coal; and lastly, in "the well dusting of it.

"The last work is to put the Powder into Barrels; every Barrel is to contain five score weight of Pow❝der, and then 'tis ready for sale.

AN

APPARATUS

TO THE

HISTORY

Of the Common Practices of

DYING.

I

By Sir WILLIAM PETTY.

T were not incongruous to begin the History "with a Retrospect into the very nature of "Light it felf (as to inquire whether the same "be a Motion or else a Body;) nor to premise some "Theorems about the Sun, Flame, Glow-worms, "the eyes of some Animals, shining Woods, Scales "of some Fishes, the dashing of the Sea, stroaks "upon the eyes, the Bolonian Slate (called by some "the Magnet of Light) and of other light and lucid "bodies.

"It were also not improper to consider the very "essentials of Colour and Transparencies (as that the "most transparent bodies, if shaped into many an "gles, present the eye with very many colours;) "That bodies having but one single superficies, have none at all, but are suscipient of every colour laid

"before

"before them; That great depths of Air make a "Blew, and great depths of Water a Greenish co"lour; That great depths or thicknesses of colour"ed Liquors do all look Blackish (red Wine in a "large Conical Glass being of all reddish colours "between black at the top and white at the bot

❝tom.

That most Vegetables, at one time or other, are "greenish; and that as many things passing the Sun

are blackned, so many others much whitened by "the same: Other things are whitened by acid "Fumes, as red Roses and raw Silks by the smoak " of Brimstone.

"Many Mettals, as Steel and Silver, become of va❝rious colours and Tarnish by the air, and by several "degrees of heat.

"We might consider the wonderful variety of colours appearing in Flowers, Feathers; and drawn "from Mettals, their Calces and Vitrifications; and ❝of the colours rising out of transparent Liquors ar"tificially mixed.

"But these things, relating to the abstracted nature "of colours, being too hard for me, I wholly de"cline; rather pasting to name (and but to name ne) "fome of the several sorts of Colorations now com❝monly used in Humane affairs, and as vulgar Trades "in these Nations; which are these: viz.

1. "There is a whitening of Wax, and several "fort of Linen and Cotton Cloathes, by the Sun, Air, and by reciprocal effusions of Water.

2. "Colouring of Wood and Leather by Lime, "Salt, and Liquors, as in Staves, Canes, and Marble "Leathers.

3. "Colouring of Paper, viz. Marbled Paper, by ❝ diftempering