They did not blow every night or many nights consecutively; otherwise all life in the valley would soon have become extinct. Adam found the hot winds heretofore, that he had imagined were those for which the valley was famed, were really comfortable compared with these terrible furnace blasts. In trying to understand their nature, Adam concluded they were caused by a displacement of higher currents of cool air. Sometime during the middle of the night there began a downward current of cool air from the mountain heights; and this caused a disturbance of the vast area of hot air in the burning valley below sea level. The tremendous pressure drove the hot air to find an outlet so it could rise to let the cool air down, and thus there came gusts and gales of furnace winds, rushing down the valley, roaring up the canyons. The camp of the Vireys, almost in the center of one of these outlets and scarcely a quarter of a mile from the main valley, lay open to the full fury of these winds. * * * * * The 1st of August was a hazy, blistering day in which the valley smoked. Veils of transparent black heat--shrouds of moving white transparent heat! The mountains’ tops were invisible, as if obscured in thin, leaden-hued fog; their bases showed dull, sinister red through the haze. Nothing moved except the strange veils and the terrible heaven-wide sun that seemed to have burst. It was a day when, if a man touched an unshaded stone with his naked hand, he would be burned as by a hot iron. A solemn, silent, sulphurous, smoky, deadly day, inimical to life!