The President of the United States, accompanied by the Secretaries of War and Interior, has been received with much enthusiasm in various places in eastern Virginia, through which he passed on his way to the White Sulphur Springs. The Secretary of State has been passing a few weeks among the lakes and mountains of New Hampshire, where he will remain probably till October; and the Secretary of the Treasury has been detained by ill health at his residence in Ohio. Reports from the various agricultural districts of the Union indicate that the wheat harvest of 1851 will be the heaviest ever raised. In New-York, Indiana, Michigan, and Wisconsin, the yield is very large, and the wheat excellent. In the Northern and Central Illinois, heavy rains have destroyed a portion of the crop, but in the Southern portion of the State it will be abundant. In Ohio, advices from all quarters of the State show that the wheat crop of the present season will be the largest ever grown in the State. In Iowa, the yield is indifferent. Of corn there will probably be an average crop. Potatoes in several parts of the country have suffered from the rot. The cholera prevails to some extent in the valley of the Mississippi, and other parts of the Southern and Western States. Among the Sioux Indians it has been very fatal. The treaty just formed with the Sioux Indians, secures to the United States all the land in the entire valley of the Minnesota, and the eastern tributaries of the Sioux, estimated at 21,000,000 of acres. From Texas, we learn that there has been great excitement at Rio Grande, in consequence of the Mexicans refusing to surrender a fugitive slave. It is said that 2,000 slaves have made their escape into Mexico.