On February 11, 1905, the Wrights received a letter from the British War Office, asking them to submit terms, and March 1, without giving formal terms, they outlined in a general way what they were willing to do. “Although we consider it advisable,” they wrote to the British War Office, “that any agreement which may be made at present be based upon a single machine and necessary instruction in its use, we would be willing, if desired, to insert in the contract an option on the purchase of all that we know concerning the subject of aviation ... “We are ready to enter into a contract with the British Government to construct and deliver to it an aerial scouting machine of the aeroplane type ...” Specifications included these: The machine to be capable of carrying two men of average weight, and supplies of fuel for a flight of not less than fifty miles; its speed, when flying in still air, to be not less than thirty miles an hour; the machine to be of substantial enough construction to make landings without being broken, when operated with a reasonable degree of skill. Another provision was that the purchase price should be determined by the maximum distance covered in one of the trial flights; £500, or about $2,500 for each mile. If none of the trial flights was of at least ten miles, then the British Government would not be obligated to accept the machine. There were further exchanges of letters between the Wrights and the British (altogether twenty-four letters in the years 1905–6), but the brothers began to suspect that the British were mainly interested in prolonging the negotiations as a means of keeping in touch and knowing what progress was being made in aviation. Probably, thought the Wrights, the British shrewdly foresaw that the flying-machine would not add to the isolation of the British Isles, and did not wish to hasten its development. But they doubtless wished to be well informed about whatever was happening in the conquest of the air. The British War Office wrote on May 13, 1905, that they were asking Colonel H. Foster, their military attaché, in Washington, to call upon the Wrights at their “works”--meaning, presumably, at their shop--and to see their machine in flight. The brothers were urged by their friend Octave Chanute on one of his visits to Dayton, to make another offer of their machine to the United States Army. Because of the treatment they had received from the War Department, the Wrights were naturally reluctant to expose themselves to further rebuffs, but Chanute was insistent that such behavior by Army people surely would not occur again. Thus prodded by Chanute, the Wrights, on October 9, 1905, wrote to the Secretary of War: