The Christians returned to their camp deploring their imprudence and credulity. This first reverse taught them that they must not always expect prodigies, and that before they proceeded further they must construct machines of war. But it was very difficult to procure the necessary wood in a country of barren sands and arid rocks. Several detachments were sent to search for materials; and chance discovered to one of them some large beams, which Tancred caused to be transported to the camp. They demolished the houses, and even the churches in the vicinity of the city which had not been given up to the flames, and every available bit of wood that had escaped the ravages of the Saracens was employed in the construction of machines. In spite of their discoveries and exertions, the progress of the siege did not answer to the impatience of the Crusaders, nor did they appear likely to be able to avert the evils that threatened them. The most intense heats of the summer set in at the very time the pilgrims arrived before Jerusalem. A scorching sun and southern winds, loaded with the sands of the desert, inflamed the horizon. Plants and animals perished; the torrent of Kedron was dry, and all the cisterns had been filled up or poisoned.[162] Under a sun of fire, and amidst burning and arid plains, the Christian army soon became a prey to all the horrors of thirst. The fountain of Siloë, which only flowed at intervals, could not suffice for such a multitude. A skinful of fetid water, brought from a distance of three leagues, cost as much as three silver deniers. Overcome by thirst and heat, the soldiers turned up the soil with their swords, and burying themselves in the freshly-moved earth, eagerly carried to their lips every moist clod that presented itself. During the day they looked anxiously for the night, and at night longed for the break of day, in the constantly disappointed hope that the return of either the one or the other would bring some little freshness, or a few drops of rain. Every morning they were seen to glue their parched lips to the marbles covered with dew. During the heat of the day the most robust languished beneath their tents, seeming not to have even strength left to implore the assistance of Heaven. The knights and barons were not at all exempt from the scourge which devoured the army, and many of them exchanged for the water of which they stood in daily need, the treasures they had won from the infidels. “Pity, on account of this extreme thirst,” says the old translator of William of Tyre, “was not so much due to the foot-soldiers as the horsemen; the foot-soldiers could be contented with a little, but the horsemen could only supply their horses with drink at great expense. As to the beasts of burthen,” adds the same historian, “there was no more account taken of them than of things already dead; they were allowed to stray away in the fields, where they died for want of water.”