It is obvious that the above explanation covers the baker's oven mystery as well. In the case of the oven, however, the inmate is concealed from start to finish, and this gives him much greater latitude for his actions. M. Chabert made the oven the big feature of his programme and succeeded in puzzling many of the best informed scientists of his day.
Eating coals of fire has always been one of the sensational feats of the Fire Kings, as it is quite generally known that charcoal burns with an extremely intense heat. This fervent lunch, however, like many of the feasts of the Fire Kings, is produced by trick methods. Mixed with the charcoal in the brazier are a few coals of soft white pine, which when burnt look exactly like charcoal. These will not burn the mouth as charcoal will. They should be picked up with a fork which will penetrate the pine coals, but not the charcoal, the latter being brittle.
Another method of eating burning coals employs small balls of burned cotton in a dish of burning alcohol. When lifted on the fork these have the appearance of charcoal, but are harmless if the mouth be immediately closed, so that the flame is extinguished.
In all feats of fire-eating it should be noted that the head is thrown well back, so that the flame may pass out of the open mouth instead of up into the roof, as it would if the head were held naturally.
To drink burning oil set fire to a small quantity of kerosene in a ladle. Into this dip an iron spoon and bring it up to all appearance, filled with burning oil, though in reality the spoon is merely wet with the oil. It is carried blazing to the mouth, where it is tipped, as if to pour the oil into the mouth, just as a puff of breath blows out all the flame. The process is continued until all the oil in the ladle has been consumed; then the ladle is turned bottom up, in order to show that all the oil has been drunk. A method of drinking what seems to be molten lead is given in the Chambers' Book of Days, 1863, Vol. II, page 278:
The performer taking an iron spoon, holds it up to the spectators, to show that it is empty; then, dipping it into a pot containing melted lead, he again shows it to the spectators full of the molten metal; then, after putting the spoon in his mouth, he once more shows it to be empty; and after compressing his lips, with a look expressive of pain, he, in a few moments, ejects from his mouth a piece of lead impressed with the exact form of his teeth. Ask a spectator what he saw, and he will say that the performer took a spoonful of molten lead, placed it in his mouth, and soon afterwards showed it in a solid state, bearing the exact form and impression of his teeth. If deception be insinuated, the spectator will say. "No! Having the evidence of my senses, I cannot be deceived; if it had been a matter of opinion I might, but seeing, you know, is believing." Now the piece of lead, cast from a plaster mould of the performer's teeth, has probably officiated in a thousand previous performances, and is placed in the mouth between the gum and the cheek, just before the trick commences. The spoon is made with a hollow handle containing quicksilver, which, by a simple motion, can be let run into the bowl, or back again into the handle at will.
The spoon is first shown with the quicksilver concealed in the handle, the bowl is then dipped just within the rim of the pot containing the molten lead, but not into the lead itself, and, at the same instant the quicksilver is allowed to run into the bowl. The spoon is then shown with the quicksilver (which the audience takes to be the melted lead) in the bowl, and when placed in the mouth, the quicksilver is again allowed to run into the handle.
The performer, in fact, takes a spoonful of nothing, and soon after exhibits the lead bearing the impression of the teeth.
Molten lead, for fire-eating purposes, is made as follows:
Bismuth . . . . . . . . . . . . . . . 5 oz.
Lead. . . . . . . . . . . . . . . . . 3 oz.
Block tin . . . . . . . . . . . . . . 2 oz.