The flora changed as they ascended; the vegetation of the tropics disappeared and was replaced by that of the temperate zone, and with each hundred feet of elevation there was a perceptible change in the temperature. Occasionally they saw some curious climbing-plants that had thrown out numerous tendrils, like arms, around the trunk of a tree, and clung to it with an embrace that could not be shaken off. The tracks of tigers and leopards were visible now and then, and the guide entertained the boys with an account of how a tiger a short time before had rushed upon a travelling party, and carried away one of the servants under the very eyes of his affrighted companions. Every little while a troop of monkeys showed itself, and when they were not visible their chattering was heard among the trees. Peacocks and wild turkeys were encountered, and one of the former was shot by the Doctor and secured by the guide, who said it would make an excellent dish for dinner. A little before sunset they came in sight of one of the tall peaks of the range, and about dusk the guide brought them to a village where they were to pass the night. It was so cold that all the bed coverings they could get together were insufficient to keep them warm, and in spite of their fatigue they were out long before daylight and ready for the return to Simla. The boys would have been quite willing to undertake the ascent of one of the mountains of the Himalayas, but the party was not equipped for such a journey, and besides, their time would not permit. So they reluctantly turned their backs on the snow-clad mountains, and returned by the way they came. [Illustration: DOOR OF A TEMPLE, AND PRAYING-MACHINES.] The guide told the boys that if they had had a week to spare he could have taken them among the loftiest mountains of that part of the range and shown them many curious things. He described a Buddhist temple in one of the passes where there were about sixty priests, or lamas, whose chief business was to offer prayers for the safety of travellers, provided they were sufficiently paid for their work. They had an easy way of saying prayers by means of a prayer-mill; it consisted of a cylinder like a small barrel, and was turned by a string fastened to a crooked handle. Every revolution of the cylinder was equivalent to a repetition of the prayer contained in it, and a skilful operator was able to turn out a great many prayers in a short time. Frank said they had seen the same thing in Japan at the entrance of one of the temples in Tokio, as well as in several other places, and the guide added that sometimes the prayers were attached to a small windmill, or to a water-wheel, so that the petition could be repeated many times while the priest in charge of it was sound asleep. [Illustration: SADDLE-OXEN IN THE HIMALAYAS.]