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.

[Illustration:  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.

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SOMZEE’S NEW GAS-BURNERS.

With the object of effecting a very intimate mixture of gas and air, and of causing this mixture to reach the point of ignition at as high a temperature as possible, M. Leon Somzee, of Brussels, has designed several new forms of gas burner, which we now proceed to describe and illustrate, from particulars and by drawings kindly supplied by an esteemed Brussels correspondent.

The high-power burner shown in Fig. 1 effects perfect combustion of the heated mixture of air and gas, which is introduced by the draught determined by the arrangement.  What chiefly distinguishes this burner from others of its class is the fact that it is perfectly suited to domestic lighting—­that is to say, it may be arranged for a comparatively small consumption of gas, while giving an increase of 250 per cent. of light.

[Illustration:  FIG. 1. and FIG. 2.  INCANDESCENT AND HIGH-POWER BURNERS.]

The burner proper is a cage or basket of specially prepared magnesia, which yields a warmer tone of light than any obtained hitherto, while not requiring so high a temperature before combustion.  The cap, made of a fire-resisting substance, fits on to a tubular arrangement, R, fixed in the upper portion of the body of the burner.  The latter is supplied by air entering at the cone, O, which terminates the inner chamber, K, of the heater, and also by that drawn in by the rising column of gas, passing before the orifices, D, which may be regulated at will.  The small burner, I, which is kept constantly alight, heats the central compartment, K, the sides of which transmit heat to the gas circulating in the annular casing, L, of the compartment.  The heated gas passes, by the passage, AA¹, into the space, C, where it becomes intimately mixed with the air entering at OP, and also with the outer air arriving by the lateral apertures, D.

The vis viva of the jet is diffused through this mixture, which thus becomes very intimate, when it penetrates into the tubular arrangement, R; combustion now taking place at the top, while the refractory cap emits a bright orange light of great steadiness.  As it is not the flow of gas which determines the entrance of the outer air, the former may be used at any pressure—­an advantageous arrangement in all respects.