To make the _Iron Run_, they mingle an equal weight of _Antimony_ (beaten in an Iron-Morter into small pieces) and _stub-Nails_ together. And preparing so many Earthen forty or fifty pounds _Melting-Pots_ (made for that purpose to endure the _Fire_) as they intend to use: They _Charge_ these Pots with the mingled _Iron_ and _Antimony_ as full as they will hold. Every time they Melt _Mettal_, they build a new _Furnance_ to melt it in: This _Furnance_ is called an _Open Furnance_; because the Air blows in through all its sides to Fan the _Fire_: They make it of Bricks in a broad open place, as well because the Air may have free access to all its sides, as that the Vapours of the _Antimony_ (which are Obnoxious) may the less offend those that officiate at the _Making_ the _Mettal_: And also because the Violent Fire made in the _Furnance_ should not endanger the Firing any adjacent Houses. They consider before they make the _Furnance_ how many Pots of _Mettal_ they intend to Melt, and make the _Furnance_ sizable to that number: We will suppose _five_ _Pots_. Therefore they first make a Circle on the Ground capable to hold these five _Pots_, and wider yet by three or four Inches round about: Then within this Circle they lay a Course of Bricks close to one another to fill the Plain of that Platform, with their broad or flat sides downwards, and their ends all one way, and on this Course of Bricks they lay another Course of Bricks as before, only the Lengths of this Course of Bricks lies athwart the Breadths of the other Course of Bricks: Then they lay a third Course of Bricks with their lengths cross the Breadth of the second Course of Bricks. Having thus raised a Platform, they place these five _Pots_ in the middle of it close to one another, and then on the Foundation or Platform raise the _Furnance_ round about by laying the Bricks of the first _Lay_ end to end and flat, close to one another: On the second _Lay_, they place the middle of a Brick over a _Joynt_ (as _Brick-layers_ call it) that is where the ends of two Bricks joyn together, and so again lay Bricks end to end till they _Trim_ round the _Platform_. Then they lay a third _Lay_ of Bricks, covering the _Joynts_ of the second _Lay_ of Bricks as before: So is the Foundation finisht.