We have met here to-day to commemorate the hundredth anniversary of the event which more than any other, after the foundation of the Government, and always excepting its preservation, determined the character of our national life--determined that we should be a great expanding nation instead of relatively a small and stationary one. Of course, it was not with the Louisiana Purchase that our career of expansion began. In the middle of the Revolutionary war the Illinois region, including the present States of Illinois and Indiana, was added to our domain by force of arms, as a sequel to the adventurous expedition of George Rogers Clark and his frontier riflemen. Later the treaties of Jay and Pinckney materially extended our real boundaries to the west. But none of these events was of so striking a character as to fix the popular imagination. The old thirteen colonies had always claimed that their rights stretched westward to the Mississippi, and vague and unreal though these claims were until made good by conquest, settlement, and diplomacy, they still served to give the impression that the earliest westward movements of our people were little more than the filling in of already existing national boundaries. But there could be no illusion about the acquisition of the vast territory beyond the Mississippi, stretching westward to the Pacific, which in that day was known as Louisiana. This immense region was admittedly the territory of a foreign power, of a European kingdom. None of our people had ever laid claim to a foot of it. Its acquisition could in no sense be treated as rounding out any existing claims. When we acquired it, we made evident once for all that consciously and of set purpose we had embarked on a career of expansion; that we had taken our place among those daring and hardy nations who risk much with the hope and desire of winning high position among the great powers of the earth. As is so often the case in nature the law of development of a living organism showed itself in its actual workings to be wiser than the wisdom of the wisest. This work of expansion was by far the greatest work of our people during the years that intervened between the adoption of the Constitution and the outbreak of the civil war. There were other questions of real moment and importance, and there were many which at the time seemed such to those engaged in answering them; but the greatest feat of our forefathers of those generations was the deed of the men, who with pack train or wagon train, on horseback, on foot, or by boat upon the waters pushed the frontier ever westward across the continent.