Nothing surprises one more than the apparent inadequacy of the means to the end attained. The Bonheur is but a small stream, yet the work it has achieved is tremendous. But it must be borne in mind that where stands Camprieu was once a lake, the water held back by the barrier of limestone, and that the accumulated force was brought to bear on the rock to effect this tunnel of drainage. Moreover, the rock itself was full of holes like a sponge, with large vaults like huge bubbles in its interior, so that it was not a solid mass through which the stream had to bore its way. It was further aided by several springs rising within the rock, all working in their several courses to effect their escape.
The exploration of Bramabiau was accomplished in June, 1888, by M. Martel and his guides. They attempted first to penetrate by the opening through which the Bonheur leaps into light again, but found that the gallery consisted of a series of ascents, with cascades and pools; and although by wading and with ladders they succeeded in reaching a considerable distance, they could not attain to the point where the stream begins to dive underground. On the following day these indefatigable explorers attacked the tunnel from above, where the Bonheur enters, and were able to descend to the point reached on the preceding day, and further to pursue their course till they came out where the stream issues, a distance as the crow flies of a kilometre.
In January, 1888, a man of Camprieu disappeared, and there was reason to suspect he had committed suicide. As his body could not be found, it was supposed that he had flung himself down the abyss of the Bonheur; and, in fact, when M. Martel searched the cavern he found the body wedged into a spot where, in the cave itself, the stream disappears underground for a while, to again reappear and continue its subterranean course. It goes through these vagaries twice, and perpetrates seven cascades.
"To avoid repetitions," says M. Martel in his account of the exploration, "I will say no more of the magic of magnesium light under vaults lofty as Gothic naves; I must only ask of the reader to figure, if he can in the profound night of these caverns, the deafening roar of the falling water, the dispersion of the party groping in all directions for passages, the flicker of the feeble candles, the distant calls and signals, whistles, and horns, the cords strained, and the ladders set up against steep walls, our silhouettes magnified against the walls in shadows, and profiled against the boiling torrent, all under vaults 150 feet high and at the extremity of galleries of 300 feet.