While reading Edgar Allan Poe's short story The thousand-and-second tale of Scheherazade (about a fantastic journey to the present of 1850) I once stumbled on the following footnote to the phrase "Another made ice in a red-hot furnace":

Place a platina crucible over a spirit lamp, and keep it a red heat; pour in some sulphuric acid, which, though the most volatile of bodies at a common temperature, will be found to become completely fixed in a hot crucible, and not a drop evaporates- being surrounded by an atmosphere of its own, it does not, in fact, touch the sides. A few drops of water are now introduced, when the acid, immediately coming in contact with the heated sides of the crucible, flies off in sulphurous acid vapor, and so rapid is its progress, that the caloric of the water passes off with it, which falls a lump of ice to the bottom; by taking advantage of the moment before it is allowed to remelt, it may be turned out a lump of ice from a red-hot vessel.

This utterly fascinated me as a child, and I always wondered if it was actually true. On searching google for information on this experiment more recently I found this from 1845 but nothing more recent:

RED-HOT PROCESS OF PRODUCING ARTIFICIAL ICE. One of the most singularly beautiful experiments perhaps ever devised, has been recently published by M. Prevostaire, illustrative of the repellent power of heat radiating from bodies at a high temperature, and of the rapid abstraction of heat, produced by evaporation, or generally by such a change of condition as largely increases the volume of any body. The experiment is simply this :—A platinum crucible is made and maintained red hot over a large spirit lamp. Some sulphurous acid is poured into it from a pipette. This acid, though at common temperatures one of the most volatile of known bodies, possesses the singular property of remaining fixed in the red-hot crucible, and not a drop of it evaporates ; in fact, it is not in contact with the crucible, but has an atmosphere of its own interposed. A few drops of common water are now added to the sulphurous acid in the red-hot crucible. The diluted acid gets into immediate contact with the heated metal—instantly flashes off into sulphurous acid vapour, and such is the rapidity and energy of the evaporation, that the water remains behind, and is found frozen into a lump of ice in the red-hot crucible, from which, seizing the moment before it again melts, it may be thrown out before the eyes of the astonished observer.—Mechanics' Magazine, No. 1066.

The occurrence of these two detailed accounts makes me suspect that this is possible, but I have not encountered anything of this sort except in these nineteenth-century sources, although it seems like it would be a pretty impressive demonstration to perform.

My question is whether this can be done or has been done recently (e.g. a video of an experiment), and does anyone know of any explicit calculations explaining how it can be done, specifically how the acid (is it sulfuric or sulfurous acid?) could remain out of contact (Leidenfrost effect?) until the addition of water (what would bring it into contact?), following which the heat of evaporation of the acid could drive the temperature of the water below freezing point, which is presumably what is being described? (Edit: as I've been informed in the comments, this is further complicated by the heat of solution of the acid and freezing point depression of the water which might take this more into the field of chemistry; any ideas on what might be going on here would be much appreciated.)

(Further edit: Having looked further for any information on this topic, I found this paper which says ‘Faraday managed to freeze mercury inside a red-hot crucible by using the same effect [Leidenfrost phenomenon]’. On looking further, I found this from 1862:

M. Boutigny, by means of sulphurous acid, first froze water in a red-hot crucible; and Mr. Faraday subsequently froze mercury, by means of solid carbonic acid... I heat this platinum crucible to glowing redness, and place within it some lumps of solid carbonic acid. I pour some ether on the acid—neither of them comes into contact with the hot crucible—they are protected from contact by the elastic cushion of vapour which surrounds them... [He then describes freezing some water in a vial using the setup]... I place a quantity of mercury in a conical copper spoon, and dip it into the crucible. The ether in the crucible has taken fire, which I did not intend it to do. The experiment ought to be so made, that the carbonic acid gas—the choke-damp of mines—ought to keep the ether from ignition. But the mercury will freeze notwithstanding. Out of the fire, and through the flame, I draw the spoon, and there is the frozen mass turned out before you on the table.

I also found this from 1923:

The same great chemist [Faraday] was experimenting in low temperatures; I remember seeing him freeze mercury in a red-hot crucible, throw the solid lump on to an anvil, and hammer it out before it melted.

Also this from 1988:

A platinum crucible is raised to red heat and then some solid carbon dioxide and a little liquid ether (to increase the thermal contact) are placed in the crucible; a metal spoon containing mercury is then lowered into the mixture. Although the crucible remains red hot, the layer of carbon dioxide gas acts as an insulator between the crucible and the freezing mixture and it remains cold long enough to freeze the mercury.

All of that, although describing a slightly different experiment which seems to involve the Leidenfrost effect and some endothermic process, makes me think that these may be involved in my experiment also. However, it seems that my experiment is more complicated since the liquid appears to come into contact with the crucible from the description. This contains an explanation of my experiment by Boutigny (who apparently discovered the experiment) from 1845 (pretty much all of my sources have been ancient) which doesn't really enlighten me:

The principle on which this experiment depends is this — sulphurous acid has the property of boiling when it is at a temperature below the freezing point; and when poured into the heated vessel, the suddenness of the evaporation occasions a degree of cold sufficient to freeze water.

Thus my question still stands: what process would be occurring to cause a breaking of the Leidenfrost effect (if that is what is described), and once done how would the resulting boiling also leach enough energy from the water to freeze it (and has anyone seen this demonstrated, since I expect it is fairly impressive)?)

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    $\begingroup$ Even more interesting because the addition of water to concentrated sulphuric acid is an exothermic reaction. $\endgroup$
    – Farcher
    Commented Oct 22, 2016 at 7:50
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    $\begingroup$ This question may be best suited for chemistry.stackexchange.com. Anyway, this could be interesting. $\endgroup$
    – valerio
    Commented Oct 22, 2016 at 8:12
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    $\begingroup$ @valerio92 I did think of posting it on chem.SE, but thought it might be more relevant to physics (with the presumed breaking of the Leidenfrost effect etc.). The link is interesting, but I wonder about its relevance since it's about dissolving the acid in water, when here we have the complicating factor of the boiling. Anyway, I've mentioned it in an edit. Ideas on whether this should be migrated would be much appreciated. $\endgroup$
    – Anon
    Commented Oct 23, 2016 at 21:55

1 Answer 1


What they were calling "sulphurous acid" back then is not what we would call an acid today. It was anhydrous sulphur dioxide which has a boiling point of $-10^\circ$C.

When liquid sulphur dioxide was poured into the red-hot vessel, due to the Leidenfrost effect, it would form itself up into globules and float on a layer of its own vapour. In this state the temperature of the globules would be just below that of its boiling of $-10^\circ$C as it evaporates away at a now greatly reduced rate. Pouring in a small amount of water, which freezes at $0^\circ$C, while the sulphur dioxide is in this state results in it freezing within a few seconds. Once all the sulphur dioxide has evaporated off, the ice will quickly melt again before being brought up to just below its boiling point of $100^\circ$C as it assumes its spheroidal form due to the Leidenfrost effect. If one is quick, before all the liquid sulphur dioxide has disappeared one can thrown out a small lump of ice from a red-hot crucible!

Update with a Reference

A source confirming the liquid sulphurous acid was indeed (anhydrous) sulphur dioxide can be found on page 645 of volume 3 of Lehrbuch der Physik by O. D. Chwolson, a copy of which can be found here. To quote, on the sixth and seventh lines down from the top of the page Chwolson writes (in German)

Boutigny brachte flüssige SO$_2$, welche bei $-10^\circ$C siedet, in einen glühenden Platintiegel, $\ldots$

which in English translation roughly reads

Boutigny brought liquid SO$_2$ [sulphur dioxde], which boils at $-10^\circ$C, into a glowing platinum crucible, $\ldots$

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    $\begingroup$ +1. Thanks for the answer; this looks like it could solve the mystery. Some references would be great before I can mark it as the accepted answer though! $\endgroup$
    – Anon
    Commented Sep 8, 2017 at 6:31
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    $\begingroup$ @Anon - I have added a reference. $\endgroup$
    – omegadot
    Commented Feb 1, 2021 at 0:40
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    $\begingroup$ Well there you have it... I never expected this answer to be updated after all this time! Thank you for going to the effort of finding that reference, and solving this question once and for all. Have your deserved checkmark! $\endgroup$
    – Anon
    Commented Feb 1, 2021 at 6:15

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