Ripley reviv'd, or, An exposition upon Sir George Ripley's hermetico-poetical works containing the plainest and most excellent discoveries of the most hidden secrets of the ancient philosophers, that were ever yet published / written by Eirenæus Philalethes ...

Rule XII.

You must then provide your self with a Furnace, by wise men called an Atha∣nor, in which you may accomplish your work; nor will any one serve in your first work; But such a one in which you may give a heat obscurely red at your pleasure, or lesser, and that in its highest degree of heat, it may endure twelve hours at the least.

This if you would obtain; Observe, First, that your nest be no bigger then to contain your dish with about an Inch vacancy at the side where the Vent-hole of your Athanor, is for the Fire to play.

Secondly, Let your Dish be no bigger then to hold one Glass with about an inch thickness of Ashes between the Glass and side, remembring the word of the Philosopher, One Glass, One Thing, One Furnace; for such a Dish standing with

the bottom level to the vent-hole, which in such a Furnace ought to be but one, about three Inches Diameter, sloping up∣wards, will with the stream of Flame, which is always playing to the top of the Vessel, and round about the bottom, be kept always in a glowing heat.

Thirdly, If your Dish be bigger, your Furnace vent must be within a third part, or a fourth as big as your Platter is Di∣ameter, else it cannot be exactly, nor continually heated.

Fourthly, If your Tower be above six Inches square at the Fire-place, you are out of proportion, and can never do rightly as to the point of heat; For if you cause it (if above that proportion) to stream with flame, the heat will be too big: And if it stream not, it will not be big enough, or very hardly.

Fifthly, Let the top of your Furnace be closed to an hole which may but just serve for casting in of Coals about three Inches Diameter or Square, which will keep down the heat powerfully.