Being disappointed in my observations of yesterday for longitude, I was unwilling to remain at the entrance of the river another day for that purpose, and therefore determined to set out early this morning; which we did accordingly; the wind was in our favour after 9 A.M. and continued favourable until 3 P.M. We therefore hoisted both the sails in the White Pirogue, consisting of a small square sail and spritsail, which carried her at a pretty good gait, until about 2 in the afternoon when a sudden squall of wind struck us and turned the pirogue so much on the side as to alarm Charbonneau [_the interpreter_], who was steering at the time. In this state of alarm he threw the pirogue with her side to the wind, when the spritsail gibing was as near oversetting the pirogue as it was possible to have missed. The wind, however, abating for an instant, I ordered Drouillard [_also an interpreter_] to the helm and the sails to be taken in, which was instantly executed, and the pirogue being steered before the wind was again placed in a state of security. This accident was very near costing us dearly. Believing this vessel to be the most steady and safe, we had embarked on board of it our instruments, papers, medicine, and the most valuable part of the merchandise which we had still in reserve as presents for the Indians. We had also embarked on board ourselves, with three men who could not swim, and the squaw [_Sacajawea, the Shoshone wife of Charbonneau, who showed the party the way across the Continental Divide and obtained horses and protection for them from the Shoshones_] with the young child, all of whom, had the pirogue overset, would most probably have perished, as the waves were high, and the pirogue upwards of 200 yards from the nearest shore; however, we fortunately escaped and pursued our journey under the square sail, which shortly after the accident I directed to be again hoisted. By the end of May the expedition had moved halfway across Montana, still following the Missouri River: