The unions representing the different trades vary in structure and spirit. There is an immense difference between the temper of the tumultuous structural iron workers and the contemplative cigar-makers, who often hire one of their number to read to them while engaged in their work, the favorite authors being in many instances Ruskin and Carlyle. Some unions are more successful than others in collective bargaining. Martin Fox, the able leader of the iron moulders, signed one of the first trade agreements in America and fixed the tradition for his union; and the shoemakers, as well as most of the older unions are fairly well accustomed to collective bargaining. In matters of discipline, too, the unions vary. Printers and certain of the more skilled trades find it easier to enforce their regulations than do the longshoremen and unions composed of casual foreign laborers. In size also the unions of the different trades vary. In 1910 three had a membership of over 100,000 each. Of these the United Mine Workers reached a total of 370,800, probably the largest trades union in the world. The majority of the unions have a membership between 1000 and 10,000, the average for the entire number being 5000; but the membership fluctuates from year to year, according to the conditions of labor, and is usually larger in seasons of contest. Fluctuation in membership is most evident in the newer unions and in the unskilled trades. The various unions differ also in resources. In some, especially those composed largely of foreigners, the treasury is chronically empty; yet at the other extreme the mine workers distributed $1,890,000 in strike benefits in 1902 and had $750,000 left when the board of arbitration sent the workers back into the mines.