1. As it is one purpose of this work to give a clear and complete account of the mode of conducting the affairs of the general government, we have thought it best to call attention to the class of officers named at the head of this chapter; and especially since persons acting under this title are assigned to a variety of duties, sometimes permanent and sometimes temporary. In the first place, they act as heads of bureaus in the various departments. These commissioners are permanent officials of the government, established and provided for by law; such are the commissioners of the land office, patent office, pension office, &c. 2. Another class of commissioners can hardly be considered officers, but rather temporary or special agents. In the multifarious duties devolving upon Congress, the President, and all the departments, it not unfrequently happens that it is impracticable for them to do certain things necessary to be done. The business to be transacted may be at a great distance from the capital, even in a foreign country. In these cases commissioners are appointed to do such business. They have been appointed to negotiate a peace, to make treaties of various kinds between us and other powers, and to negotiate with the Indians for the purchase of their lands. The United States c............