Lewis: July 16, 1804

Monday 16th we set out at an early hour; the morning was cloudy; could
find no convenient situation for observation; proceeded untill a little
before noon when we came too On the Lard. Shore opposite to the center of
good Island where I observed the meridian altitude of O’s L. L. with
Octant by the back observation, wich gave me the Latitude40° 20′
12″ N.

I now set the Chronometer as near noon as this observation would enable
me, and proceeded untill evening, when we came too on the Stard. shore
opposite the lower point of the Island of the Bald prarie where we
encamped.