i jo Singing Valleys 



so forced down again. The wheel's turning turned a shaft 

 which entered the side of the mill and joined the tedder which 

 it caused to revolve. An undershot wheel is planned to be 

 turned by the current of the stream in which it rests. Naturally 

 its usefulness is affected by seasons of high or low water. Nor 

 can an undershot wheel be used in streams where the current 

 runs at a distance from the shore. 



The principle of the windmill is that of the screw-driven 

 ship. The sails, made of light wooden lattice, are fitted with 

 canvas louvres. These permit of being opened so that the wind 

 may blow through, leaving the mill at rest. When closed, they 

 offer resistance to the wind which forces them around. The 

 veering sails revolve a shaft which turns the upper millstone 

 inside the windmill. 



The problem of how to keep the sails in the constantly 

 changing wind was solved by building the early mills on stout 

 wooden posts. The post was fixed securely to the ground, but 

 a wooden bearing atop this permitted the heavy superstructure 

 which was the mill-house, to be swung round, thus bringing 

 the sails into the prevailing wind. Later on, engineers devised 

 a way of building towers with the mills high up in them. A 

 wooden cap on the tower revolved on a large bearing. The 

 sails were fastened to the cap. Many of the windmills still turn- 

 ing in the Netherlands are of this design. In England, where 

 the wooden facing of the towers was frequently painted white, 

 they were called "smock mills." 



Recently a man digging on the site of an old mill pond near 

 Orangeburg, South Carolina, discovered a set of mill gears 

 made of southern oak which, according to Professor B. W. 

 Dedrick of State College, Pennsylvania, an authority on old 

 American mills, "may be the oldest pieces of machinery in 

 America." 



Do these gears which are apparently parts of three separate 

 mill wheels (the largest nineteen feet in circumference) solve 

 the mystery of the "lost colony" which left Roanoke Island 



