The art of glass shewing how to make all sorts of glass, crystal and enamel : likewise the making of pearls, precious stones, china and looking-glasses : to which is added, the method of painting on glass and enameling : also how to extract the colours from minerals, metals, herbs and flowers ... : illustrated with proper sculptures / written originally in French, by Mr. H. Blancourt, and now first translated into English ; with an appendix, containing exact instructions for making glass-eyes of all colours.

CHAP. CXCIV. The Furnace for making of China,

MUST be large, with an Opening proportioned to the Vessel you are to place therein; of these there are several sorts, but the most commodious must be made as follows.

You may shape this Furnace round or square, but the square is best, because of the Opening; it must be made of good Brick and such Stuff as can mostly en∣dure the Fire, of what bigness you please, with three Divisions; the lowest for the Ashes must be a Foot high, that the Air may be communicated through its Opening to the Fire; the middle Story is for the Fire, and must be underlaid with a very good Grate to se∣parate it from the under Story, with an Opening for the Fuel, and be vaulted above about a Foot in heighth: According to the Size of your Furnace this Vault must be made like that of an Oven, and have an Hole in the middle of the same shape as the Furnace, round or square, and proportioned to its bigness, through which the Flame may transmit it self to the uppermost Story, where the Vessels are put to bake in; this last Story is to be at least two Foot high, and its Opening fourteen or fifteen Inches, to put and draw the Vessels easily in and out; the top must be vaulted too with such a round or square hole, and over that a Funnel, for the conveniency of the Flame and Smoak which it draws out.

All the Opening, especially the two uppermost, must be of strong Brick, or Crucible Earth, or ra∣ther of Iron, well luted within side, which must shut and open easily, and be very exact and sit, that the

Fire may not suck in any cold Air, which might break the Vessels.

This Furnace will serve also for many other uses, as to Melt, Reverberate, Calcine, Cement, and seve∣ral sorts of Works in the Laboratory of Chimistry; because in it all the degrees of Fire may be found by the help of the lower Opening, and the Funnel of the Chimney.

You may else for Baking your China, make use of the Furnace hereafter described in Chap. 202. where we discourse of Painting on Glass, putting thereinto your Vessel of Crucible-Earth for Baking the Ware in, and then cover'd over with a vaulted Coverlid, with a hole at top to let out the Flame and Smoak of the Reverberatory Fire; for this reason there will be no occasion in this sort of Furnace for any other Open∣ing, because the Baking Vessels with your Ware, are put in a top before the Coverlid is laid on, and so the Fire circulates about it, and it becomes very Red, whereby the China-Ware is Baked, as is done in Ba∣king of Pipes.