Pike objected to many of the evident signs of British sovereignty: the British flag flying above the headquarters of the department of Fond du Lac was shot down;[13] many of the Indians were induced to give up their British medals and flags;[14] and Hugh M'Gillis, agent of the company for the district, in response to Pike's letter of complaint, promised in the future to refrain from displaying the British flag, presenting medals, or talking politics to the Indians.[15] But his promises were no more seriously given than those of his brethren on the Missouri. Little of permanent value would have been accomplished if the acts of the explorer on September 23, 1805, had been omitted. The instructions issued to Pike on July 30, 1805, stated: "You will be pleased to obtain permission from the Indians who claim the ground, for the erection of military posts and trading-houses at the mouth of the river St. Pierre [the Minnesota River], the falls of St. Anthony, and every other critical point which may fall under your observation; these permissions to be granted in formal conferences, regularly recorded, and the ground marked off."[16] When Pike reached the mouth of the Minnesota River, the natural features of the locality convinced him of the advantages which would arise from a fort located at that point. From the high bluff lying between the Minnesota and the Mississippi rivers the course of both streams would be under the sweep of the guns. Sheer walls of stone rising from the Mississippi could prevent invasion; and the fur trading business could be regulated, as all boats entering or leaving the Indian country must use one or the other of the two rivers. A "bower" was constructed of sails, and on September 23rd Pike spoke to the Sioux Indians there assembled concerning the transfer of Louisiana, the futility of their wars with the Chippewas, and the evils of rum. He asked them to cede to the United States lands for military posts, and dwelt on the value of these posts to the Indians. To this the chiefs assented, receiving in return presents valued at $200 and sixty gallons of liquor. The terms of the treaty provided that the Sioux should cede to the United States tracts "for the purpose of establishment of military posts," at the mouth of the Minnesota and at the mouth of the St. Croix. A money consideration was also mentioned, but a blank was left which was later filled in by the Senate with $2000.[17]