The Scoop Wheel, 79 



the door always remained closed. To obviate this movable 

 breasts have recently been fitted to some of the old wheels, 

 which can be raised or lowered to suit the level of the water. 

 The wheel at Podehole has thus been altered (see Plate 5). 

 On the breast of the outlet sill an iron plate has been fitted 

 in a recess cut in the masonry. This plate is hinged to 

 another plate which lies on the floor of the outlet channel 

 By means of a segmental-toothed rack geared into a pinion 

 on the windlass this movable breast can easily be raised or 

 lowered, and the sill of the discharging channel adjusted to 

 the height of the water. A similar arrangement has been 

 carried out in the large wheel on the Hundred Foot River, 

 and the discharge in both cases has been very greatly im- 

 proved. Experiments made by the superintendent of the 

 latter wheel showed that with the same pressure of steam in 

 the boiler, and other circumstances being the same, the number 

 of revolutions of the wheel — 50 feet in diameter — increased 

 about one-third, or from 31 in three minutes, with the 

 movable breast lowered, to 41 in the same time when it was 

 raised its full height of 4 feet, making a total rise of 8 feet 



In 1868 Mr. Samuel Nay lor, the superintendent of the 

 Morton Car drainage district on the Trent, took out a patent 

 for a somewhat similar arrangement, which is thus described 

 in the patent specification : " At the end of the channel or 

 chase of the wheel is formed a face, and at the bottom 

 thereof, m a horizontal axis, is an-anged a flap or valve 

 constructed so that it will float, and jointed at intervals. 

 This flap floats in the water, allowing the water in the 

 wheel to pass it in an upward direction. When the level 

 of the water falls by the stopping of the wheel, and the flow 

 tends towards the wheel, the flap floats up to its face and 

 makes a tight joint, and so prevents the return of the water " 

 — Patent specification, irth March, 1868, No. 839, The 

 difference between Mr. Naylor's plan and that already 

 described is that the former is self-adjusting, and also 



