struck by their own authority, or by that of the respective States;
fixing the standard of weights and measures throughout the United
States; regulating the trade and managing all affairs with the Indians,
not members of any of the States; provided that the legislative right of
any State, within its own limits, be not infringed or violated;
establishing and regulating post offices from one State to another,
throughout all the United States, and exacting such postage on the
papers passing through the same as may be requisite to defray the
expenses of the said office; appointing all officers of the land forces
in the service of the United States, excepting regimental officers;