4–7. Assigns to survey, in addition to those already assigned, Captain John W.T. Gardiner, 1st dragoons; Second Lieutenant Johnson K. Duncan, 3d artillery; Second Lieutenant Rufus Saxton, 4th artillery; Second Lieutenant Cuvier Grover, 4th artillery; and Brevet Second Lieutenant John Mullan, 1st artillery; and twenty picked men of the 1st dragoons and two officers and thirty men to Captain McClellan’s party.
8. The administrative branches of the army, on requisition approved by Governor Stevens, to supply the officers, soldiers, and civil employees of the expedition (except the scientific corps and their assistants), with transportation, subsistence, medical stores, and arms, and to furnish funds for the same when not supplied in kind.
9–10. After completion of field work, the expedition to rendezvous at some suitable point in Washington Territory to be designated by Governor Stevens, and reports to be prepared. Officers and enlisted men to be sent to their stations and employees to be discharged.
11. $40,000 set apart from the appropriation for the survey thus intrusted to Governor Stevens.
It is difficult to realize the magnitude of the task here outlined. It was to traverse and explore a domain two thousand miles in length by two hundred and fifty in breadth, stretching from the Mississippi River to the Pacific Ocean, across a thousand miles of arid plains and two great mountain ranges, a region almost unexplored, and infested by powerful tribes of predatory and warlike savages; to determine the navigability of the two great rivers, the Missouri and the Columbia, which intersect the region; to locate by reconnoissance and to survey a practicable railroad route; to examine the mountain passes and determine the depth of winter snows in them; to collect all possible information on the geology, climate, flora and fauna, as well as the topography, of the region traversed; and finally to treat with the Indians on the route, cultivate their friendship, and collect information as to their languages, numbers, customs, traditions, and history; and all this, including the work of preparation and organization, to be accomplished in a single season.
It was Governor Stevens’s plan to effect this vast work by means of two parties operating simultaneously from both ends of the route, the principal one starting from St. Paul at the eastern end, under his own immediate charge; and the other, starting from the western end, under McClellan, to meet on the upper Columbia plains between the two great mountain ranges; and two subsidiary parties,—one, under Lieutenant Donelson, to ascend the Missouri to Fort Union with a stock of supplies, and there await the coming of the main party; and the other, under Lieutenant Saxton, to proceed from the lower Columbia to the Bitter Root valley, in the heart of the Rocky Mountains, with an additional stock of supplies for the main party. The subsidiary parties were also to examine the country traversed by them, and collect all the information possible bearing on the various objects of the expedition. By this plan McClellan was required simply to explore the Cascade Range, or about 200 miles of the route; while Governor Stevens allotted all the remainder, some 1800 miles, including the great plains, the Rocky and Bitter Root Mountains, to the parties under his immediate charge.
During the next four weeks Governor Stevens drove forward the work of preparing and organizing the expedition with tremendous energy. He applied for and obtained the assignments of officers and men from the army; made requisitions upon the administrative branches for supplies and funds for the several parties; obtained $6000 from the Interior Department for the purchase of Indian goods and for treating with them; employed A. W. Tinkham, his former assistant at Fort Knox, and Fred. W. Lander, afterwards the Brigadier-General Lander who was wounded at Ball’s Bluff and died of his wounds, as civil engineers; appointed George W. Stevens as secretary and astronomer; placed Professor Baird, of the Smithsonian, in charge of the zoölogical and botanical collections, and of preparing the outfits and instructions for field work; made Isaac Osgood, his former clerk at Bucksport, disbursing officer; Dr. John Evans, geologist; Drs. George Suckley and J.G. Cooper, surgeons and naturalists; J.M. Stanley, artist, and engaged a number of other subordinates, including six young gentlemen who went as aides.
Early in April Lieutenant Saxton and Lieutenant Duncan started for the Columbia via the Isthmus and San Francisco, with detailed instructions, that no time might be lost in organizing the western parties, and were followed by McClellan as soon as he reached Washington from Texas and received his instructions. He was also furnished by Governor Stevens with letters from Sir George Simpson to the officers of the Hudson Bay Company’s posts, and with letters from the governor to many of the prominent American settlers in Washington and Oregon, and also a circular letter bespeaking their goodwill and support for Captain McClellan.
Governor Stevens also placed under McClellan’s charge the construction of a military wagon-road from Fort Steilacoom, on Puget Sound, to Fort Walla Walla on the Columbia, for which Congress had appropriated $20,000, and which the Secretary of War had placed in Governor Stevens’s hands, with authority to assign an officer or a civil engineer to its construction, as he deemed best. The governor gave very full instructions in regard to this road; furnished the names of prominent citizens and advised McClellan to consult with them as to the best location for the road, and gave him full notes of his correspondence with them bearing on the matter.
Sir George Simpson having proposed to forward an extra stock of supplies to his posts in the interior for the expedition, Governor Stevens made haste to decline the proffered assistance, not wishing to incur such an obligation to a foreign company, assuring Sir George that his own government would provide ample supplies, and that he merely wished to know what the company’s posts could spare from their usual stock in case of emergency. On this point he is emphatic in his instructions to Saxton and McClellan:—