Water wheel, 19th century design plans. This type is known as a compound water wheel as it uses both the undershot and breast wheel principles. The double-fronted sluice (lower left) simultaneously admits water to the base (undershot) and center (breast wheel), allowing more water to fill each section (cut-away F) thus turning the wheel with a greater force. The volume of water could be adjusted with the mechanism at upper left (K), which could change the flow of water. At this time water wheels were used to grind corn, raise water and power machinery. Taken from The Circle of the Sciences", published in London 1862-7."