kindly supplied to me by Mr J. Orten Boving, M.I.M.E., of 72 Victoria Street, Westminster. Such vanes in ordinary cases would be moved by hand, but on electrical plants a special oil-pressure governor, actuated by a force pump driven off the main shaft, is used. Then there is the scroll regulator. It consists of a circular scroll, very like a venetian blind, upon which is fixed a strip of leather or rubber attached to small strips of wood or bronze; two rollers, actuated by gearing from a hand-wheel, roll up the scroll around themselves, and so set the turbine in motion. The mechanism, being delicate, is very liable to get out of order. The same method of regulation as shown by fig. 604 is applicable to inward-flow vertical-shaft turbines by means of a circular ring outside the guides, the guide passages on one side of the turbine being higher than those on the opposite side. The two half-rings are able to slide off their respective passages without affecting the other. As an example of a very large-power turbine having a vertical shaft, we give figs. 619 and 620. It is of a type similar to those running at Niagara Falls power station, U.S.A., and is shown in full detail. There are two wheels, and each wheel, for the purpose of efficient regulation, is divided by diaphragms into 3 circular rings; the slides shown, when moved by hand or by governor, close or open the passages as required. Figs. 621-2-3 show a turbine for falls varying from 30 to 120 ft. It is a form well adapted to direct-drive, and runs at a fairly high speed. For electrical work a flexible coupling must be provided. The actual turbine of the Francis type will develop 100 B.H.P. under 33-ft. head, running at 500 R.P.M. The regulation is illustrated, 617 and 618. Altogether the design (by Mr J. Orten Boving) is worthy of attention. Head Throttle Valve Handwheel for Qi Pressure Flywheel with FIGS. 621, 622, and 623. The Francis turbine shown in drawings Nos. 624-5-6 is of a type used for low heads of from 4 to 15 ft., the machine being placed in an open flume. On account of the low speed an increase of about 1:3 is obtained by means of bevel gear, and by this means a direct-drive from the horizontal shaft can, as a rule, be used. Drawings Nos. 627-8-9 show a horizontal Francis turbine suitable for heads of from 10 to 30 ft. When the head approaches the latter figure a considerable portion can, if desired, be taken up in suction head, thus obviat. ing the necessity for a very deep pit. Fig. 640 shows a good design of impulse turbine direct-coupled to an electric generator, with a direct-acting governor driven by gearing from the main shaft. As an example of what could be done with a small turbine installation we have figs. 630 and 631. It is fully described, and was specially designed by the author for a small workshop. It will be seen that owing to the low fall it was only necessary to place the turbine on a timber head race. The plant as erected gave every satisfaction. We have now to describe one more type of water motor, which is so simple in manufacture and construction, and yet when well designed will give such excellent results. It is known as the pelton wheel, and is illustrated in figs. 632 and 633. It consists of a plain disc, mounted on a wood or cast-iron frame, having a number of curved buckets placed at equal distances apart on the periphery; a conical nozzle is attached to the supply pipe, and directs a jet of water on to each of these in turn, while the buckets have a central division (or knife-edge) to deflect it into two portions, outwards and backwards. There is no doubt that for high falls, and in out-of-the-way places, for driving every class of machinery, the |