The Collaborative International Dictionary
Athanor \Ath"a*nor\, n. [F., fr. Ar. at-tann[=u]r, fr. Heb.
tann[=u]r an oven or furnace.]
A digesting furnace, formerly used by alchemists. It was so
constructed as to maintain uniform and durable heat.
--Chambers.
Wiktionary
n. a furnace or stove, designed and used to maintain uniform heat. Primarily used by alchemists
WordNet
n. a self-feeding furnace that maintains a uniform temperature; used by alchemists
Wikipedia
In alchemy, an athanor is a furnace used to provide a uniform and constant heat for alchemical digestion. Etymologically, it descends from a number of Arabic texts of the period of the Califate which use the term "al-tannoor" in talismanic alchemy, meaning a bread-oven, from which the design portrayed evidently descends.
The athanor was also called Piger Henricus ("Slow Harry"), because it was chiefly used in slower operations, and because when once filled with coals, it keeps burning a long time. For this reason the Greeks referred to it as "giving no trouble", as it did not need to be continually attended. It was also called the Philosophical furnace, Furnace of Arcana, or popularly, the Tower furnace.
Usage examples of "athanor".
Had Lully used his skill in astrology not only to ensure that the best planetary influences should preside over the ignition of the athanor but also, Nostradamus-like, to forecast the future, he could have predicted dire fortunes for England and all Europe within a couple of years.
And in this welter of spoiled treasure were the great conjuring books hurled amid the ruin of retorts and aludels of glass and lead and silver, sand-baths, matrasses, spatulae, athanors, and other instruments innumerable of rare design, tossed and broken on the chamber floor.
Arranged about the floor were brick athanors, or furnaces, with bellows and tongs hanging ready for use.
The athanor would require a stone tower to be attached laterally, filled with fuel, thus ensuring a constant supply as new fuel dropped down to fill the space vacated by fuel already consumed.
I repeat if, I can maintain an intense, constant heat in my athanor for a sufficient length of time, then we shall witness a marvel in the heart of my furnace which will save us from worrying unduly about fuel and heat.
Had Lully used his skill in astrology not only to ensure that the best planetary influences should preside over the ignition of the athanor but also, Nostradamus-like, to forecast the future, he could have predicted dire fortunes for England and all Europe within a couple of years.
The rays of the lamps that illumed it were saffron-red like the spilt ichor of devils, and they flowed on aludels and crucibles and black athanors and alembics whereof the purpose was hardly to be named by mortal man.
And in this welter of spoiled treasure were the great conjuring books hurled amid the ruin of retorts and aludels of glass and lead and silver, sand-baths, matrasses, spatulae, athanors, and other instruments innumerable of rare design, tossed and broken on the chamber floor.
On a coffee table, as in a dentist's office, were slick magazines, in casual disarray, with titles like Literature and Wit, The Poetic Athanor, The Rose and the Thorn, The Italic Parnassus, Free Verse.