At nearly every camp, too, a wagon was abandoned, and for miles they could look back and see its white cover, looming above the dreary expanse of sand and sage, like a monument to the faithful animals that had fallen beside it. At length but one wagon and the two ambulances were left. Tents, baggage, clothing, all the bedding except one blanket apiece, and the greater part of their provisions, had been thrown away, or left in the abandoned wagons. Within forty miles of the mountains they gave up work on the line. The men had no longer the strength to drag the chain or carry the instruments. They still noted their course by compass, and the height of various elevations as they crossed them, by the barometer. They were even able to measure the distance from one sad camping-place to another, by means of the odometer, an instrument that, attached to a wagon-wheel, records the number of revolutions made by it. This number, multiplied by the circumference of the wheel, gave them the distance in feet and inches. Everybody was now on foot, even the chief's saddle-horse, Señor, and Glen's Nettle being harnessed to one of the ambulances.