=Power to Call Extraordinary Sessions.=--The President has power to call extraordinary sessions of Congress for the consideration of special matters of an urgent character. Of course the President cannot compel Congress to adopt his recommendations at a special session any more than at a regular session, but he can sometimes hasten action and if he is backed by a strong public opinion he may be able to accomplish even more. The authority to call extraordinary sessions has been exercised by Presidents Adams, Jefferson, Madison, Van Buren, Harrison, Pierce, Lincoln, Hayes, Cleveland, McKinley, Roosevelt, Taft, and Wilson. In all these cases Congress was called together to deal with extraordinary situations such as foreign difficulties, financial panics, rebellion, the enactment of appropriation bills which had failed at the regular session, the enactment of tariff bills for which there was an urgent demand, the approval of reciprocity treaties, and the like. The senate has often been convened in extraordinary session at the beginning of a new administration for the purpose of approving the nominations of the President, but the house of representatives has never been called alone. =Power to Adjourn Congress.=--The President is also authorized to adjourn the two houses in case of disagreement between them as to the time for adjourning the session. Only one such case of disagreement has ever occurred, namely, in the special session of November, 1903, when the senate proposed to adjourn and the house of representatives refused. President Roosevelt did not, however, exercise his power in this case, so the special session continued about two weeks longer, until it was ended by the beginning of the regular session. =Power to Issue Ordinances.=--Under the legislative functions of the President may also be included what is known as the ordinance power, that is, the power to issue certain orders and regulations having the force of law. Such are the regulations for the government of the army and navy, and those relating to the postal service, patents, pensions, public lands, Indian affairs, the customs service, internal revenue service, marine hospital service, the consular service, the civil service, and many other branches of administration. Some of these regulations are issued by the President under express authority conferred upon him by acts of Congress; others are issued as a result of the necessity of prescribing means for carrying into effect the laws of Congress and sometimes of interpreting them;[82] while still others are issued in pursuance of the constitutional powers of the President. Such are the regulations issued for the government of the army and navy, in pursuance of the authority of the President as commander in chief.