The foundation of this vast organization was the interest of particular trades rather than the interests of labor in general. Its membership is made up "of such Trade and Labor Unions as shall conform to its rules and regulations." The preamble of the Constitution states: "We therefore declare ourselves in favor of the formation of a thorough federation, embracing every trade and labor organization in America under the Trade Union System of organization." The Knights of Labor had endeavored to subordinate the parts to the whole; the American Federation is willing to bend the whole to the needs of the unit. It zealously sends out its organizers to form local unions and has made provision that "any seven wage workers of good character following any trade or calling" can establish a local union with federal affiliations. This vast and potent organization is based upon the principle of trade homogeneity--namely, that each trade is primarily interested in its own particular affairs but that all trades are interested in those general matters which affect all laboring men as a class. To combine effectually these dual interests, the Federation espouses the principle of home rule in purely local matters and of federal supervision in all general matters. It combines, with a great singleness of purpose, so diverse a variety of details that it touches the minutiæ of every trade and places at the disposal of the humblest craftsman or laborer the tremendous powers of its national influence. While highly centralized in organization, it is nevertheless democratic in operation, depending generally upon the referendum for its sanctions. It is flexible in its parts and can mobilize both its heavy artillery and its cavalry with equal readiness. It has from the first been managed with skill, energy, and great adroitness. The supreme authority of the American Federation is its Annual Convention composed of delegates chosen from national and international unions, from state, central, and local trade unions, and from fraternal organizations. Experience has evolved a few simple rules by which the convention is safeguarded against political and factional debate and against the interruptions of "soreheads." Besides attending to the necessary routine, the Convention elects the eleven national officers who form the executive council which guides the administrative details of the organization. The funds of the Federation are derived from a per capita tax on the membership. The official organ is the American Federationist. It is interesting to note in passing that over two hundred and forty labor periodicals together with a continual stream of circulars and pamphlets issue from the trades union press.