Page:History of the Royal Society.djvu/304

 Saligni Carbonis atque una Sulphuris, Convenitque magnis Machinis; Sed Midiocribus Halinitri partes decem, Saligni carbonis tres, Sulphuris duas, parvis vero Halinitri partes decem; Carbonis ligni nucis Avellonæ sine nodis, tum Sulphuris partem unam singularem: Langius appoints three of Peter, two of Withy Coal, and one of Brimstone: The English Author of Fire-works, says, that the proportions in England to make good, indifferent, and ordinary Powder, is 5, 4, and 3 parts of Peter, to two of Coal, and one Brimstone. Our English Workmen are generally so curious of their secret, that I could not obtain the proportion of them without a promise of Secrecy: But when all is done their secret is not so much the way to make the best Powder, as the best way to get most money by it, by subtracting from the Peter, and making up weight with the Coal; when indeed there is so great a Latitude, that provided the Materials be perfectly mixt, you make good Powder with any of the proportions above-mention'd; but the more Peter you allow it, it will still be the better, till you come to observe eight Parts.

'The next thing after the proportion, is the mixture, about which most of the workmens time and pains is bestowed: For first in a Horse-mill with two stones (like that with which they grind their Materials at the Glass-house) moving upon a Marble bottom, which is edged with boards set sloaping, that what slips from under the stones may slide back again.

'They grind the Brimstone and Coal each of them apart by themselves as fine as possibly they can; then they sift each of them apart by themselves: Rh