Sub. What's cohobation?
Face. 'Tis the pouring on
Your aqua regis, and then drawing him off,
To the trine circle of the seven spheres.
Sub. And what's your mercury?
Face. A very fugitive; he will be gone, sir.
Sub. How know you him?
Pace. By his viscosity,
His oleosity, and his suscitability."
Even in the fourteenth century, Chaucer (in the "Canon's Yeoman's Tale") depicts the alchemist as a mere cunning knave. A priest is prevailed on to give the alchemist money, and is told that he will be shown the change of base metal into gold. The alchemist busies himself with preparations, and sends the priest to fetch coals.
"And whil he besy was, this feendly wrecche,
This false chanoun (the foule feende him fecche)
Out of his bosom took a bechen cole
In which ful subtilly was maad an hole,
And therein put was of silver lymayle
An unce, and stopped was withoute fayle
The hole with wex, to keep the lymayle in.
And understondith, that this false gyn
Was not maad there, but it was maad before."
This "false gyn" having been put in the crucible and burned with the rest of the ingredients, duly let out its "silver lymayle" (filings), which appeared in the shape of a small button of silver, and so accomplished the "false chanoun's" end of deceiving his victim.