I had in mind to climb Sierra Blanca the following day, and hoped to spend the night in a ranch house on the northern slope of this great peak. Toward sundown Rob and I climbed through a pole fence and entered the ranch house-yard. Round a corner of the house came a boy racing on a willow switch pony. On seeing us, he stopped, relaxed his hold on the willow and started for Rob. How happily he ran, holding out both eager hands! The dog sprang playfully backward, and began to dodge and bark as the boy laughingly and repeatedly fell while trying to catch him. Just as I entered the house, Rob was trying to climb to the top of the fence after his new playmate. That night Rob was agreeable with every one in the house, and even had a romp with the cat. These people wanted to keep him, and offered money and their best saddle-horse. I knew that with them he would have kind treatment to the day of his death. I wanted him, too, but I knew the weeks of mountain-exploring just before me would be too hard for him. "Rob is a free dog," I said, "and is, of his own choice, simply traveling with me as a companion. I cannot sell or give him away. I like him, but, if he wants to stay, it will be a pleasure to me to leave him." The next morning every one was wondering whether Rob would go or stay. The dog had made up his mind. He watched me prepare to leave with keenest interest, but it was evident that he had planned to stay, and his boy friend was very happy. As I passed through the yard, these two were playing together; at the gate I called good-by, at which Rob paused, gave a few happy barks, and then raced away, to try to follow his mountain boy to the top of the old pole fence. Sierra Blanca Sierra Blanca I was rambling alone on snowshoes, doing some winter observations in the alpine heights of the Sangre de Cristo range. It was miles to the nearest house. There was but little snow upon the mountains, and, for winter, the day was warm. I was thirsty, and a spring which burst forth among the fragments of petrified wood was more inviting than the water-bottle in my pocket. The water was cool and clear, tasteless and, to all appearances, pure. As I rose from drinking, a deadly, all-gone feeling overcame me. After a few seconds of this, a violent and prolonged nausea came on. Evidently I had discovered a mineral spring! Perhaps it was arsenic, perhaps some other poison. Poison of some kind it must have been, and poisonous mineral springs are not unknown. The sickness was very like seasickness, with a severe internal pain and a mental stimulus added. After a few minutes I partly recovered from these effects and set off sadly for the nearest house of which I had heard. This was eight or ten miles distant and I hoped to find it through the guidance of a crude map which a prospector had prepared for me. I had not before explored this mountainous section.