already made may be useful and proper, during the present session of Congress, and of the Legislatures of those States through which the route passes, the commissioners respectfully state that at a very early period it was conceived that the maps of the country were not sufficiently accurate to afford a minute knowledge of the true courses between the extreme points on the rivers, by which the researches of the commissioners were to be governed; a survey for that purpose became indispensable, and considerations of public economy suggested the propriety of making this survey precede the personal attendance of the commissioners.
"Josias Thompson, a surveyor of professional merit, was taken into service and authorized to employ two chain carriers and a marker, as well as one vaneman, and a packhorse-man and horse, on public account; the latter being indispensable and really beneficial in accelerating the work. The surveyor's instructions are contained in document No. 1, accompanying this report.
"Calculating on a reasonable time for
