The sovereign authority of a trade union is its general convention, a delegate body meeting at stated times. Some unions meet annually, some biennially, some triennially, and a few determine by referendum when the convention is to meet. Sometimes a long interval elapses: the granite cutters, for instance, held no convention between 1880 and 1912, and the cigar-makers, after a convention in 1896, did not meet for sixteen years. The initiative and referendum are, in some of the more compact unions, taking the place of the general convention, while the small executive council insures promptness of administrative action. The convention elects the general officers. Of these the president is the most conspicuous, for he is the field marshal of the forces and fills a large place in the public eye when a great strike is called. It was in this capacity that John Mitchell rose to sudden eminence during the historic anthracite strike in 1902, and George W. Perkins of the cigar-makers' union achieved his remarkable hold upon the laboring people. As the duties of the president of a union have increased, it has become the custom to elect numerous vice-presidents to relieve him. Each of these has certain specific functions to perform, but all remain the president's aides. One, for instance, may be the financier, another the strike agent, another the organizer, another the agitator. With such a group of virtual specialists around a chieftain, a union has the immense advantage of centralized command and of highly organized leadership. The tendency, especially among the more conservative unions, is to reëlect these officers year after year. The president of the Carpenters' Union held his office for twenty years, and John Mitchell served the miners as president ten years. Under the immediate supervision of the president, an executive board composed of all the officers guides the destinies of the union. When this board is not occupied with the relations of the men to their employers, it gives its judicial consideration to the more delicate and more difficult questions of inter-union comity and of local differences. The local union is the oldest labor organization, and a few existing locals can trace their origin as far back as the decade preceding the Civil War. Many more antedate the organization of the Federation. Not a few of these almost historic local unions have refused to surrender their complete independence by affiliating with those of recent origin, but they have remained merely isolated independent locals with very little general influence. The vast majority of local unions are members of the national trades union and of the Federation.