[F] St. John, The I. W. W.—Its History, Structure and Methods (1917 ed.), p. 23.
[G] The figures in column 3 are from Professor Geo. E. Barnett, "Membership of American Trade Unions," Quarterly Journal of Economics, vol. xxx, p. 846 (August, 1916). His figures come, apparently, from I. W. W. headquarters in Chicago, but they do not agree entirely with those furnished the author by Secretary St. John.
[H] In this and some of the following columns more than one figure has been included in years for which varying estimates were found. The sources for column 4 are as follows: Proceedings 2nd I. W. W. Convention, p. 60; Report of the I. W. W. to the Stuttgart International Socialist Congress, Industrial Union Bulletin, Aug. 10, 1907, p. 4; Bulletin New York State Department of Labor, no. 67 ("International trade union statistics"), p. 3; Louis Levine, "The development of syndicalism in America," Political Science Quarterly, vol. xxviii, p. 478 (Sept., 1913); Vincent St. John's testimony before U. S. Commission on Industrial Relations (Final Report and Testimony, vol. ii, p. 1456; Weekly People, Dec. 9. 1916, p. 1, col. 3).
[I] Leo Wolman, "Extent of labor organization," Quarterly Journal of Economics, vol. xxx, p. 603 (May, 1916). Wolman shows sex distribution as follows:
| Chicago I. W. W.: | males | 7137, | females | 2000. |
| Detroit I. W. W.: | males | 3130, | females | 345. |
[J] Number issued between February 1910, and October, 1911.
[K] For the Detroit I. W. W. Approximate number issued during the textile workers strikes.
[L] Accumulated number from 1905.
[M] For the Detroit I. W. W. Approximate. October 1, 1908, to February 1, 1915.
[N] Sources: Industrial Worker (I), August, 1906; Miners Magazine, Sept. 7, 1905, p. 15; Marot, American Labor Unions, p. 59; St. John, op. cit., p. 23.