The next day we were traveling on the back bone of a little ridge. There was no timber except a few scattering Juniper trees. We were now in Arizona, and water was very scarce. The reader will understand that Carson invariably rode from fifty to one hundred yards ahead of the command, and I always rode at his side. I presume it was between two and three o'clock in the afternoon when Col. Freemont called out to Carson, "How far are you going tonight?" Carson studied a minute and answered, "I think, in seven or eight miles we will find good water and a plenty of grass." A few minutes after this Freemont said, "Say, Carson, why not go to that lake there and camp? There is plenty of grass and water," at the same time pointing to the south. Carson raised his head and looked at the point indicated. Then he said, "Col. there is no water or grass there." Freemont replied, "Damn it, look. Can't you see it?" at the same time pointing in the direction of what he supposed to be the lake. Carson checked his horse until Freemont came up near him and then said, "Col., spot this place by these little Juniper trees, and we will come back here tomorrow morning, and if you can see a lake there then I will admit that I don't know anything about this country." Freemont was out of humor all the evening. He had nothing to say to any person. The next morning after breakfast was over and the herder had driven in the horses Carson said, "Now Colonel, let's go and see that lake." Under the circumstances Freemont could not say "no." I think five of us besides Carson and Freemont went back. When we came to the place where the little Juniper trees were, Freemont's face showed that he was badly whipped, for sure enough there was no lake there; he had seen what is called a mirage. I have seen almost everything in mirage form, but what causes this Atmospheric optical illusion has never been explained to my satisfaction. Some men say it is imagination, but I do not think it is so. On our way back to camp a man by name of Cummings was riding by my side. He made the remark in an undertone, "I am sorry this thing happened." I asked him, "Why?" In reply he said, "Colonel Freemont won't get over this in many a day, for Carson has shown him that he can be mistaken."