government. The principal officer in the Department of State. He shall perform such duties as shall be enjoined on or entrusted to him by the president, agreeably to the constitution, relative to the correspondences, commissions or instructions to or with public ministers or consuls from the United States, or to negotiations with foreign states or princes, or to memorials or other applications from foreign public ministers or foreigners, or to such other matters respecting foreign affairs as the president of the United States shall assign to such department. The secretary shall conduct the business of his department in such manner as the president shall, from time to time, order or instruct.