MILLS. 71 
the masonry of the mill; c, arms of the wheel; p, sockets of cast-iron upon 
the axle which receive the iron arms c, and the wooden ones 5; F, circles or 
annular plates of cast-iron made in segments, bolted or screwed together, and 
also secured to the iron arms c; @, an interior ring of wood which received the 
arms E ; H, grooves for the reception of the ends of the buckets ; x is the driv- 
ing gear, with teeth on its interior periphery, made fast to one of the annular 
plates ; m is the gearing for raising and depressing the gates; », crank for 
driving the same; 0, pinion driving cog-wheel p, on shaft g (jig. 9), which 
carries another pinion, engaging with the rack r of the apron or gate, which 
is thereby raised and lowered in the grooves in the side-walls of the flume. 
2. HorizontaL WaAteR-WHEELS. 
Horizontal water-wheels differ essentially in their construction and opera- 
tion from those already described. Pl. 15, fig. 19, is a vertical section of a 
turbine as improved by Fourneyron. F is the vertical axle which carries 
the horizontal water-wheel, from which the power is communicated in any 
known way to the machinery to be driven. 
This shaft is stepped into the lever, x, having its fulerum at P, and adjust- 
able by means of the screw, M, upon the rod, L, so that the wheel with its 
shaft may be raised or lowered at pleasure; at the foot of the axle is secure 
the concave disk which terminates in the annular plate, a, upon which are 
fixed the vertical curved buckets, @. These buckets perform a duty analo- 
gous to that fulfilled by the buckets of the vertical wheels, receiving the 
impulse of the water and transmitting it to the machinery to be driven: nn 
is a tube by which the step, m, is oiled. The water flows from the flume 
above into a cylinder, pp, and thence into the cylinder containing the curved 
guides, 6, b (pl. 15, figs. 19 and 20), which serve to guide the water upon 
the wheel, that it may strike the buckets perpendicularly. This cylinder 
rests upon a flange, 2, of the tube, a, which surrounds the shaft of the wheel, 
the latter turning freely whilst the guide cylinder remains stationary. In 
order to regulate the force of water upon the wheel, the cylindrical gates, 
c, are so arranged as to be raised or lowered by the rods, 5, attached to the 
ring, d@, to which the gates, c, are secured. 
At the bottom of the gate, c, are wooden wedges, so formed as to fit into 
the guide curves, and close the openings to the water-wheel in proportion as 
the gate is depressed. 
Pl. 15, fig. 21, is a section ; fig. 22 a front view, and jig. 23 a plan of a 
turbine of a little different construction, which will be easily understood 
from what has gone before; / is the water way; A the gate. The back- 
water passes off through the channel, a, and above is seen, at b, m, ”, the 
machinery for transmitting the power. 
In order to lessen the friction upon the step of the vertical shaft in wheels 
of this description, Nagel in Hamburg conceived the idea of admitting the 
water to the wheel from below, instead of above, which he did with the 
happiest. effects, increasing the power of the wheel from 55 per cent. to 80 
651 
