New Philosophical Furnaces

8

[the distance] of one finger's breadth, extending a little out of the furnace, so that if they Referring to the bars of the grate mentioned on the previous page. become blocked, they can be gripped with tongs, moved, and cleaned of burnt material; and afterward they can be properly put back in their places. For this reason, it is also necessary that the furnace be open in its front part, namely under the grate, so that you can better handle the grate.

It is also necessary that the furnace have a stone or earthenware cover original: "tectum" on top, provided with a hole in the middle, with a certain groove original: "distinctione"; likely a channel or rim for a sand-seal. to be filled with sand, so that the lid placed upon it can properly close that hole, so that the spirits Vapors or gases produced during the chemical process. cannot escape, but are instead forced to exit through the pipe into the receivers, after you have thrown in the material to be distilled.

On the Receiving Vessels.

Receiving vessels should be made of glass, or of strong earth High-fired stoneware or clay. that can retain spirits, such as that from Waldburg, Hesse, Frechen, Siegburg, etc. These regions in Germany were famous during the Renaissance for producing "Stoneware" (Steinzeug) capable of withstanding high heat and acidic chemicals. Those made of glass are better, provided the glassworks are not lacking, and indeed they should be made of strong and firm glass. These can be polished and leveled with emery emery: "simirite", a granular rock used as an abrasive to grind glass surfaces for a perfect fit. around the joints, so that they may be joined better, and then there is no need for luting luting: "lutatione", the process of sealing joints in laboratory apparatus with a paste or clay "lute" to make them airtight. (how they are polished and leveled with emery will be taught in the fifth part, which deals with manual operations) because they are joined so tightly in this way that no spirit can escape through the joints. Otherwise, the joints must be secured with the best luting, which does not permit spirits to escape, as will be taught in the [next] book...