However the Astorians decided to send an expedition into the interior to verify the story given by the two Indian women, but, just as they were ready to go, a large canoe with the British flag floating from her stern appeared, from which, when it had reached the landing, there leaped ashore an active, well-dressed man who introduced himself as David Thompson, of the North-west Company. This was the same man, the reader will remember, who had crossed the Rocky Mountains the year before, had wintered near the head of the River, and had then descended it, seeking a location for the Columbia River emporium of the Canadian company. But he was too late. It was quite strange by what narrow margins on several occasions the British failed to forestall the Yankees. On July 23d the delayed expedition of the Astorians set forth far to the interior, and as a result of their investigations, David Stuart, in charge of the party, began the erection of a trading house at the mouth of the Okanogan, five hundred and forty miles above Astoria. It was on September 2, 1811, that this post was begun, and hence Fort Okanogan may be regarded as the first American establishment in the present State of Washington. It was antedated a few months by the post of the North-west Company at the entrance of the Little Spokane into the Spokane, near the present site of the City of Spokane. During the fall of 1811 the Indians around Astoria became very threatening. Direful rumours, too, in regard to the destruction of the _Tonquin_ began to disquiet the Astorians. In the emergency the wary McDougall, then acting as the head of the Company, bethought himself of a very effective expedient. He had learned that dreadful loss of life among the Indians had resulted a few years before from smallpox and that the Indians were mortally afraid of it. Calling into his room several of the principal chiefs, he asked if they remembered the smallpox. Their serious faces were sufficient proof that they did. McDougall then held up a small vial and continued with awful solemnity: "Listen to me. I am the great smallpox chief. In this little bottle I keep the smallpox. If I uncork the bottle and let it out I will kill every man, woman, and child of the Indians. Now go in peace, but if you make war upon us I will open the bottle, and you will die." The chiefs filed out in terror, and peace was preserved.