TURBINE necting the wheel to its vertical Bhaf t ; F, G, G' are supporting beams ; S the shaft ; I the support for the bearings ; J the driving gear ; FIG. 1. Section of Boyden Turbine. and R the apparatus for moving the gate. In the Boyden wheel is illustrated the outward- flow turbine. In the inward-flow wheel, the water enters between guide curves, or is car- ried in a spiral channel, and the form of the buckets of the wheel is modified in accordance with the principles already stated, and gives the form seen in plan in fig. 3, in which A is the wheel disk and B is the shaft. In the parallel-flow turbine the water enters upon FIG. 2. Plan of Boyden Torbine. Fio. 8. Inward-flow Turbine, Plan. the wheel as in fig. 4, which represents the Bodine turbine. It is cased in so that it may be set at any point in the fall, utilizing the so-called suction of that part below it, as well as the pressure due to the column above it, a method of arrangement first introduced by Henschel and Jonval. The wheel was invent- ed by Fontaine. The upper set of guides are fixed; the lower set are the wheel buckets In the Burnham turbine, fig. 5, the inward and downward flow forms are combined to make a wheel of very high efficiency, while yet cheap in construction and durable. In the Leffel wheel, fig. 6, the stream is divided to Main the combined inward and downward flow and to secure greater effectiveness, and also to obtain more perfect regulation. This form has been extensively introduced in the United States, as has also the preceding. The FIG. 4. Bodine Turbine, Parallel Flow. same letters denote the same parts in each figure. The arrows indicate the direction of flow. In Schiele's inward-flow turbine the FIG. 5. Burnham Turbine. Inward and Downward Flow. water divides on entering the wheel, a part passing out above, the remainder emerging below, the wheel disk. The Fourneyron out-
