The Chancelade quarries near Perigneux, which caved in Oct. 22, 1885, under circumstances that are still fresh in the minds of all, have gained a celebrity that renders it unnecessary for us to revert to the details of the catastrophe. It will suffice to recall the fact that after the accident a private committee was formed for the purpose of making an attempt to save the five victims who had been surprised in the drifts, and who happened to be in the bottom levels.
FIG. 1. - PHOTOGRAPHIC EXPLORING APPARATUS.
The Lippmann establishment at once offered to make a boring by means of which it would be possible to communicate with the galleries in which the men were imprisoned, but, despite the most active efforts, success was found impossible. In order to satisfy public opinion, the committee resolved to bore a well 12 inches in diameter to a depth of 23 feet, that should permit of reaching the gallery; but this did not render the latter accessible. How was it to be seen what had occurred, how was it to be made certain that the men were dead, and that all hope of rescue must be abandoned? To Mr. Langlois, a Parisian photographer, was confided an order to construct a special apparatus which might be let down to the bottom of the well by a cord, and which, being capable of operating from a distance, should furnish the required information through sensitized plates. As may be seen, this operation presented peculiar difficulties, although Mr. Langlois was enabled to overcome these with much skill.
The photographic apparatus that the ingenious operator constructed was contained in a metallic case that could be let down into the bore hole. The upper and lower parts of the contrivance were provided with incandescent lamps, that could be lighted or extinguished from a distance, by means of conductors. The photographic apparatus, properly so called, formed of an objective and camera with its sensitized plate, was inclosed in a cylinder 3½ inches in diameter. By means of a cord drawn at the mouth of the well, the apparatus could be made to issue from its vertical sheath, and to pivot around its axis so as take views in different directions (Fig. 1).
The entire affair was suspended by twelve-foot iron rods, connected with each other end for end.
In using the apparatus, the operating was done in a shanty, which served as a dark room. The device was let down into the bore well until it touched bottom. At this moment a cord was pulled so as to raise the camera, and then a few moments were allowed to elapse in order that the apparatus might become immovable. As the objective was all the time in the dark, it had neither cap nor shutter, but was unmasked from the beginning of the operation.
In order to form an impression on the plate, it was only necessary to give light; this being easily done by passing an electric current by means of a commutator, so as to light the incandescent lamps. At the end of the exposure, the lamps were extinguished and the entire apparatus was immersed in darkness. The mean time of exposure was from four to five minutes. The apparatus was then hauled up, and the negative developed.
The experiments could be renewed as often as necessary, and the apparatus be pointed in all directions by turning it a certain number of degrees by means of a lever attached to the upper rod. In this way were obtained various views of the inaccessible gallery in different planes.
FIGS. 2 AND 3. - REPRODUCTION OF PHOTOGRAPHS TAKEN IN THE INACCESSIBLE GALLERIES.
We reproduce herewith two of Mr. Langlois' most interesting photographs. One of these shows the head of the corpse of a young miner whose face stands out in relief against the side of the gallery (Fig. 2) the other shows a wheel and a lot of debris heaped up pell-mell (Fig. 3).
The series of proofs obtained from small negatives, two inches square, gave the completest sort of information in regard to the aspect of the subterranean gallery.
The exact place where the boring had been done and the entire and broken pillars were recognized, as was also the presence of two corpses, thus showing that it was indeed here that it would have been necessary to act in order to render aid to the unfortunates.
FIG. 4. - FAULT THAT CAUSED THE ACCIDENT.
In Fig. 4 is shown the appearance of the great fault that caused the accident at Chancelade. It seems to us that this method of photographing inaccessible subterranean galleries ought to receive numerous applications in the future. - La Nature.