Page:Philosophical Transactions - Volume 012.djvu/126

 Though this fault be most found in this sort of Iron; yet, if in the working of their Best sort they omit any one Process, it will be sure to want some part of its Toughness, which they esteem its perfection.

Irst Pigs of clean and soft Lead are cast into thin Plates a yard long, six inches broad, and to the thickness of the back of a Knife. These are rolled, with some Art, round; but so as the Surfaces no where meet to touch: for where they do no Ceruss grows.

Thus roll'd, they are put each in a Pot just capable to hold one, upheld by a little Bar from the bottom, that it come not to touch the Vinegar, which is put into each Pot, to effect the conversion.

Next a square Bed is made of new Horse-dung, so big as to hold 20 Pots abreast, and so to make up the number of 400 in one Bed.

Then each Pot is covered with a Plate of Lead; and lastly all with Boards, as close as conveniently can be. This repeated four times, makes one heap, so called, containing 1600 Pots.

After three Weeks the Pots are taken up, the Plates unrolled, laid upon a Board, and beaten with Battle-dores till all the Flakes come off. Which, if good, prove thick, hard and weighty: if otherwise, fuffy and light; or sometimes black and burn'd, if the Dung prove not well order'd: and sometimes there will be none.

From the Beating-Table the Flakes are carried to the Mill; and with Water ground between Millstones, until they be brought to almost an inpalpable fineness. After which it is moulded into smaller parcels, and exposed to the Sun to dry till it be hard and so fit for use.

That two Pots alike ordered, and set one by the other, without any possible distinction of advantage, shall yield, the one thick and good Flakes, the other few, and small or none: which happeneth in greater quantities, even over whole Beds sometimes.