Mr. W. M. Buchanan's Theory of the Reaction Water- Wheel. 115 



but vrhcre a deficiency is felt, and especially in districts destitute of 

 mineral resources, there is an inducement amounting often to necessity, 

 to apply that agency which Nature affords with strict reference to the con- 

 dition of maximum economy. It is this economy of means which consti- 

 tutes the true problem in the transfer of water-power, and which has 

 found a now and complete solution in the Reaction Water- Wheel. 



Description of tlie Machine: — The Reaction Wheel in its improved 

 and best form, consists of two metal discs, between which the diaphragms, 

 forming the lateral limits of the two water-channels, or arms, are fixed. The 

 transverse sections of these channels are rectangular at all points of 

 their length, but continually diminish in area according to a certain law, 

 from the base to the orifice. The water is admitted to the interior of 

 the machine by a circular opening in the undermost disc, and thence 

 flows radially outwards in the channels, and finally escapes by the orifices 

 at the circumference in lines tangential to the circle of revolution. This 

 direction of the jets is obtained by a curvature of the arms conforming to 

 a definite law which, for our present purpose, it will be sufficient to des- 

 cribe as a simple deflexion of the axes of the channels through an arc of 

 ninety degrees. The circular margin of the central opening, through 

 which the water is admitted into the machine, is formed with a projecting 

 ledging, truly adjusted by turning in a lathe, to the equal and concentric 

 edge of 'a compound and adjustible ring called the mouth-piece, and which 

 is fitted upon the recurved end of the supply-pipe. These annular 

 labra (of the central opening and mouth-piece) being brought lightly (not 

 pressed) into contact, a water-joint is produced possessing all the advan- 

 tages of a packed-joint without its inconvenience and friction. 



The arrangement will be rendered more fully intelligible, by reference 

 to the accompanying figures, (Plate in.) in which a denotes the machine, 

 b its vertical shaft, by which the power is carried to any required height, c 

 the water-joint, formed by the coincidence of the projecting margin of the 

 central opening and the edge of the rising-ring d, of the mouth-piece ; 

 e is the collar-ring, into which the rising-ring d is fitted water-tight 

 by turning, and which is secured by bolts to the horizontal flange of the 

 recurved end of the supply-pipe/. This flange is commonly of large size, 

 and rectangular form, to allow of its being batted to a foundation of 

 stone. 



The part d of the mouth-piece, it will bo observed, admits of vertical 

 adjustment, in case of wear, at the joint. When the diameter does not 

 exceed a certain limit (2 ft.), it is fitted into the collar-ring by chasing, 

 and can therefore be adjusted at any time by a simple horizontal move- 

 ment. When the parts become too largo to be conveniently chased, they 

 are fitted together by plane turning, and rendered water-tight by a small 

 packing let into a groove cut in the periphery of the rising-ring d In 

 this case the vertical adjustment is accomplished by a number of set screws 

 made to act on the two contiguous flanges. 



By theso means, a connexion of the most simple and complete kind is 



