He added that he had directed stockade works "aided by blockhouses" to be erected at Vincennes, "Chikago" and at other places, "in conformity with the sketch herewith enclosed." The details of the plan are further described in the letter as follows: "The blockhouses to be constructed of timber slightly hewed," and the magazines to be of brick "of a conic figure," each capable of receiving from fifty to one hundred barrels of powder. "The blockhouses," he continued, "are to be so placed as to scour from the upper and lower stories the whole of the lines." The plan thus outlined was followed in the construction of Fort Dearborn as well as of other forts generally along the frontier. Three pieces of light artillery composed the armament of the fort, until at a later time another gun was added, and in a magazine constructed for the purpose was stored the necessary ammunition. Directly west of the fort, fronting toward the river, was built a double log house, between the two parts of which an open passage was left, though the roof was made continuous over both portions as well as over the open passage. Along the front and rear a veranda extended the full length of the structure. This building was the Agency House, or United States Factory, used for storing goods to be sold to the Indians under Government regulations. For a number of years, from 1796 to 1822, the United States supplied goods to the Indian tribes at many places on the frontier in exchange for their furs. In these exchanges the Government's policy was to deal with the Indians on an equitable basis, providing them protection against the rapacity of the traders, many of whom swindled them unmercifully. It may be said in passing that this benevolent purpose on the part of the Government was completely frustrated. The traders supplied their savage customers with liquor, which the Government agents were not at liberty to do, and thus the Indians preferred to do business with the former in spite of the lower prices and superior quality of the goods furnished by the latter. In 1822, the "Factory System," as it was called, was discontinued entirely. For many years previous to the building of Fort Dearborn a substantial dwelling had been standing on the opposite side of the river, near the present foot of Pine Street. This house was built by a man named Jean Baptiste Point de Saible, a native of San Domingo and a negro, some time before 1779, as appears from a report made by Colonel De Peyster, the commander at Michilimackinac during the British occupation.