Friday, July 20.  There was a heavy dew last night, and this morning was foggy and cool.  We passed at about three miles distance, a small willow island to the north, and a creek on the south, about twenty-five yards wide, called by the French, L’eau qui Pleure, or the Weeping Water, and emptying itself just above a cliff of brown clay.  Thence we made two and a half miles to another island; three miles further to a third:  six miles beyond which is a fourth island; at the head of which we encamped on the southern shore; in all eighteen miles.  The party, who walked on the shore to-day, found the plains to the south, rich, but much parched with frequent fires, and with no timber, except the scattering trees about the sources of the runs, which are numerous and fine.  On the north, is a similar prairie country.  The river continues to fall.  A large yellow wolf was this day killed.  For a month past the party have been troubled with biles, and occasionally with the dysentery.  These biles were large tumours which broke out under the arms, on the legs, and, generally, in the parts most exposed to action, which sometimes became too painful to permit the men to work.  After remaining some days, they disappeared without any assistance, except a poultice of the bark of the elm, or of Indian meal.  This disorder, which we ascribe to the muddiness of the river water, has not affected the general health of the party, which is quite as good, if not better, than that of the same number of men in any other situation.

Saturday, July 21.  We had a breeze from the southeast, by the aid of which we passed, at about ten miles, a willow island on the south, near high lands covered with timber, at the bank, and formed of limestone with cemented shells:  on the opposite side is a bad sandbar, and the land near it is cut through at high water, by small channels forming a number of islands.  The wind lulled at seven o’clock, and we reached, in the rain, the mouth of the great river Platte, at the distance of fourteen miles.  The highlands which had accompanied us on the south, for the last eight or ten miles, stopped at about three quarters of a mile from the entrance of the Platte.  Captains Lewis and Clarke ascended the river in a periogue, for about one mile, and found the current very rapid; rolling over sands, and divided into a number of channels; none of which are deeper than five or six feet.  One of our Frenchmen, who spent two winters on it, says that it spreads much more at some distance from the mouth; that its depth is generally not more than five or six feet; that there are many small islands scattered through it, and that from its rapidity and the quantity of its sand, it cannot be navigated by boats or periogues, though the Indians pass it in small flat canoes made of hides.  That the Saline or Salt river, which in some seasons is too brackish to be drank, falls into it from the south about thirty miles up, and a little above it Elkhorn river from the north, running