Why is Saint James the Less sometimes represented by a windmill in Christian symbology?

According to Emblems of Saints by Frederick Charles Husenbeth (A. H. Goose & Co., 1882), the emblem of a windmill for James the Less stems from his martyrdom, having been beaten to death with a "fuller's club." Pictured in the south parclose screen at St. Helen's church in Ranworth, Norfolk, in England, there is a painting of the child St. James the Less at his mother's feet holding a toy mill meant to represent a fuller's mill. Thus a "fuller's mill" over centuries became a windmill, now a symbol of the saint. --Hilarie Cornwell Chico, Californiaauthor, "Saints, Signs, and Symbols, Third Edition," coming from Morehouse Publishing in 2009.www.CornwellScribeWorks.com