to him freely the information requisite for the purposes of the journey.
While attending too, at Lancaster, the fabrication of the arms with
which he chose that his men should be provided, he had the benefit of
daily communication with Mr. Andrew Ellicot, whose experience in
astronomical observation, and practice of it in the woods, enabled him
to apprise captain Lewis of the wants and difficulties he would
encounter, and of the substitutes and resources offered by a woodland
and uninhabited country.

Deeming it necessary he should have some person with him of known
competence to the direction of the enterprise, in the event of accident
to himself, he proposed William Clarke, brother of general George Rogers
Clarke, who was approved, and, with that view, received a commission of
captain.

In April, 1803, a draught of his instructions was sent to captain Lewis,
and on the twentieth of June they were signed in the following form:

"To Meriwether Lewis, esquire, captain of the first regiment of
infantry of the United States of America:

"Your situation as secretary of the president of the United States,
has made you acquainted with the objects of my confidential message
of January 18, 1803, to the legislature; you have seen the act they
passed, which, though expressed in general terms, was meant to
sanction those objects, and you are appointed to carry them into
execution.

"Instruments for ascertaining, by celestial observations, the
geography of the country through which you will pass, have been