By Tillmann Taape
When sifting through early modern alchemical recipes, I am often struck by their inherent dangers which would make modern-day health and safety officers pull their hair out. Renaissance practitioners were remarkably unfazed by temperatures high enough to melt glass and metal, and they frequently recommended heating volatile and flammable liquid in sealed glass vessels which, by their own admission, had a tendency to crack if not handled with the utmost care. Surely these exploits must have gone wrong a lot of the time, resulting in burnt fingers or a faceful of boiling alcohol?
If we look at the stereotype of the alchemist in contemporary satirical literature, it seems that accidents came with the job. In his Ship of Fools (1494), German humanist and satirist Sebastian Brant echoes themes from medieval poetry in his depiction of the alchemist: a greedy and reckless fool whose dangerous and fruitless exploits leave him scarred, financially ruined and even blind.  As a source of historical information, satirical genres should of course be taken with a generous pinch of salt. It is significant to note, though, that early modern people saw alchemy as a potentially dangerous thing to do, even in times long before anything like today’s health and safety standards.
More direct evidence of alchemical disasters is, unfortunately, fairly rare. I would of course be delighted to be persuaded otherwise by readers of this blog, but to me it seems that while adepts of alchemy frequently wrote down instructions which sound like they might well blow up, they were frustratingly silent on whether this actually happened. I was quite thrilled, therefore, when I finally stumbled upon a first-hand account of an alchemical disaster: exploding stills, knocked-out practitioners and all. In his 700-page tome entitled Liber de arte distillandi de compositis or Large book of distillation, first published in 1512, my favourite surgeon-apothecary Hieronymus Brunschwig (introduced here and here) includes the following cautionary tale.
Brunschwig was distilling turpentine to separate the watery fraction from the valuable oil, and when nearly all of the water had come out, he was interrupted.
I was called away to a patient, so the oil went into the water, and when I came back, a layer of oil was sitting on top of the water. I didn’t have the sense to simply decant off the oil, so I poured the lot into a new flask and thought I’d just extract the water by distillation. But I was called away again, and in the meantime the water evaporated from the oil, and some of it condensed on the side of the flask and dripped back into the oil, which rose inside the flask with a great tumult, and fumes erupted from the flask, blowing off the alembic. 
Things got worse when Brunschwig came back late at night and went to investigate the accident, telling his servant to bring along a light:
When the light arrived, the fumes touched it, and fire burst forth all around, and in the blink of an eye went out again, nevertheless burning off mine and my servant’s hair, clothes and eyebrows. We fell to the ground and did not know where we were, but before long we got up again and fetched a closed lantern so the same thing would not happen again, and threw ashes in the furnace to smother the fire. 
And this, dear readers of the Large book of distillation, is how you do NOT distill turpentine! Once the initial excitement about this truly adventurous tale had worn off, I realised that, to the historian, there was more to this anecdote than merely the satisfying confirmation that some procedures which look so precarious on paper did indeed go up in fire and smoke. In his description of this extraordinary incident, Brunschwig also reveals a number of interesting details about his everyday life and work. We get a glimpse of what it meant for an early modern practitioner to have multiple vocations. Juggling his alchemical activities with his duties as an apothecary and surgeon, it seems that Brunschwig could be called away to the aid of a patient at a moment’s notice, even at night. We also learn that he had at least one servant, and we can surmise that he did his distillations in an enclosed workshop, since a buildup of explosive fumes would be unlikely in the open air. Perhaps most importantly of all, this anecdote provides strong evidence that Brunschwig was actively performing many of the procedures he describes in his works, rather than just copying and compiling them for publication.
Anecdotes like these, then, are more than just an entertaining read and a well-earned reward for ploughing through hundreds of pages of Brunschwig’s Alsatian dialect with its erratic spelling. Descriptions of extraordinary events also grant us a glimpse into the reality of practicing alchemy, and into practitioners’ everyday life.
 On the stereotypes and changing ‘personae’ of early modern alchemists, see Tara Nummedal, Alchemy and Authority in the Holy Roman Empire. Chicago: University of Chicago Press, 2007, Ch. 2.
 Brunschwig, Hieronymus. Liber de arte distillandi de compositis […]. Strasbourg: Grüninger, 1512.