and Calcination, which are of dry ſubſtances, unleſs I ſhall by the way make uſe of either in relation to the perfecting of any kind of Diſtillation.
Now becauſe all, or moſl of theſe Diſtillations are to bee
performed by heat, it will be neceſſary to underſtand how many degrees of heat there are, and which are convenient for
every operation, and they are principally four.
The firſt is only a warmth, as is that of Horſe dung of the Sun, of warm water, and the vapour thereof, which kind of heat ſerves for putrefaction, and digeſtion.
2. The ſecond is of ſeething water, and the vapour thereof, as alſo of aſhes, and ſerves to diſtill thoſe things which are ſubtile, and moiſt, as alſo for the rectifying of any Spirit or Oil.
3. The third is of ſand and filings of Iron, which ſerves to diſtill things ſubtle, and dry, or groſs and moiſt.
4. The fourth is of a naked fire, cloſe, open, or with a blaſt which ſerves to diſtill Metals and Minerals, and hard gummie things, as Amber; &c. I doe not ſay ſerves only to diſtill theſe, for many of the former Diſtillations are performed by this heat, as the diſtilling of Spirits and Oils, &c. in a Copper ſtill over a naked fire; but theſe may be diſtilled by the two former degrees of heat; but Minerals and ſuch like cannot but by this fourth degree alone.
Of the matter and form of Furnaces
THe matter of Furnaces is various, for they may be made either of brick and clay, or clay alone with whites of Eggs, hair,and filings of Iron, (and of theſe if the clay be fat are made the beſt, and moſt durable Furnaces) or of Iron, or Copper caſt or forged. The forms alſo of Furnaces are various. The fitteſt form for Diſtillation is round; for ſo the heat of the fire being carryed up equally diffuſeth it ſelf every way,
