Actually, the Spanish Inquisition was super lenient towards witches compared to the rest of Europe. In fact, it was part of inquisition policy to give more mild punishments to witches than Jews or Muslims. For example, if a Jewish converso was found to have relapsed back into Judaism, they were automatically killed. Not so for witches. In addition, inquisitors were allowed to confiscate the property of those accused of being relapsed jews, while the confiscation of property was forbidden in the case of witches (although this was sometimes violated, as by Diego de Sarmiento of Barcelona, but he was removed from the case because of it).
In 1611-1614, an inquisitor named Alonso de Salazar conducted a multi-year long investigation in the Basque country of Spain, where there was some witch fever going on (accusations left and right, local burnings, even an Inquisition auto de fe held in 1609). He wanted to learn the truth, and through cross-examining the witches, he realized most of them were lying, confessing about dreams or making up stories in hopes of their confessions making the Inquisition treat them more leniently -- and then they'd point out neighbors who'd do the same (or try to **** over people they didn't like). He also conducted experiments to test the validity of their claims, like the various potions/ointments they said could kill cattle and children. When tested on cattle, sheap, etc. and on one of the accused witches... nothing happened.
He finally wrote back to the Grand Inquisitor saying this was all nonsense, and they believed him! Spanish Inquisition stopped its persecution of witches, while the rest of Europe continued to go nuts.
Couldn't say for sure but I would guess that he poured a small amount of denser than air combustible gas and allowed it the spread out throughout the room. Lit it, the gas ignites and then burns out harmlessly.
We did something similar in my college chem class. Chances are it is a tube filled with methane gas condensed in liquid nitrogen then lit on fire as it starts to boil at room temperature. Then the liquid is thrown across the ground while on fire and boils quickly against the warmer ground.
I was so excited to study economics....
I gave up on inventing because of maths,
Sciencing too, math is always in the way of my dreams.
But I'm trying very hard.
Good luck ! Thankfully I'm already done with everything, I've already danced naked in the moonlight to celebrate the last maths lecture of my life. Well, even after that chemistry kept on being maths in disguise but well.