_Monday, May 28th._—At noon to-day I rode out about five miles from our camp to visit some gentlemen who reside on the site of one of the old Missions. It was once the residence of the Methodist missionaries, who seem to have succeeded the Roman Catholic priests in some parts of this country. For what reason, I know not, they appear to have abandoned their ground, and when the old _adobe_ buildings stood vacant, being well situated, with timber around, they were taken by these gentlemen who were endeavoring to raise stock, to sell to emigrants crossing the plains, or settlers who will soon be "locating" themselves through these valleys. They have since abandoned it and moved fifty miles farther into the interior to a claim of their own. About a stone's throw from the house are the graves of Dr. Whitman and his family, (seven in number,) who were murdered in 1847, by a band of Cayuses. He was, I believe, physician to the Mission. We spent the afternoon at the Nez Percé camp, where a band of some thirty young warriors were engaged in dancing and singing. Their musical instruments are few in number and of the rudest kind. The singing is very harsh, and to us, who listened to it only as a collection of sounds, seemed utterly discordant. The songs are almost entirely extemporaneous, like the Improvisatore recitations of the Italians, a narrative of some past events, or perhaps suggested by the sight of persons present, or by trifling circumstances known to the audience. We never saw the women dancing, and believe they rarely do, and never with the men. During the dancing we had a little interlude in the shape of a speech. A young chief delivered it, and at the end of each sentence it was repeated in a louder voice by one of the old men. This repetition is their invariable custom, and a crier seems to be a necessary accompaniment to all their villages. To-day, leading chiefs belonging to some of the most distant tribes, attended by their followers, have been coming in to the camp, and most of those for which the Commissioners have been waiting are now represented. Their encampments and lodges are scattered over the valley for more than a mile, presenting a wild and fantastic appearance. The Council will probably open to-morrow. According to the original orders received by Lieutenant Gracie, this was to have been our last day here, but foreseeing this delay, Governor Stevens had some time ago sent an express to the Dalles, stating the necessity for the soldiers remaining. To-day the express returned, bringing instructions from Major Haller to Lieutenant Gracie, authorizing him to remain on the Council-ground until the treaty was concluded, and informing him that provisions had been sent to the escort for seven days more.