Chap. VIII.
B III TAIN.
5-17
was placed work of a like kind, and, according to the calculation made by Mr. Beighton,the effect was as follows : —
In the first arch next the city was one wheel, with double work of sixteen forcers.
In the third arch there were three wheels, with fifty-two forcers, and one revolution ofeach wheel made two strokes and a fifth, so that one turn of the four wheels made 114strokes.
When the river was in its best state the wheels went six times round in a minute, andbut four and a half at middle water.
The number of strokes then in a minute was six times 114, or 684. 'The 2 feet 6-inchstroke in a 7-inch bore raising three gallons of water per minute, made the whole quantityraised in that time 2052 gallons, or in the day 46,896 hogsheads were raised to the heightof 120 feet.
The power by which the wheels were moved was thus calculated: —the weight of thecolumn of water on a forcer 7 inches in diameter, and 120 feet in height,
7 x 7 = 49 pounds average in a yard nearly.
40 yards high.
1960 pounds in one forcer.
8 forcers always lifting.
15680 pounds, the weight at one time on the engine.
This is equivalent to seven tons weight: then as the crank pulls the lever 3 feet from theforcer, and 8*3 feet from the centre,
7 tons.
11*3
8*3)79*1(9'5 tons to the crank.
Wallower 2-2)9-5(4-3 tons on the trundle,
The spur-wheel 4
The radius of great wheel 10)17-2(1-72 tons.
The force of the floats 18 cwt. 14 lbs. 34*40 cwt
But, to allow friction and velocity, may be reckoned at l£ tons.
The ladles or paddles, 14 feet long, 18 inches deep 22*4 square feet.
The fall of water sometimes 2 0 feet.
Contents in a cube footPounds to a gallon
44-8
6 gallons.
268-810
112)2688(24 cwt.
'Hie velocity of the water 4 feet in 21'" of time,
21"' : 4 feet :: 60" : 685 feet per minute.
The quantity expended on the wheel, according to the velocity of the stream, was 1433hogsheads per second, and the velocity of the wheel was to the velocity of the wateras 1 to 22".
In the year 1767 it was discovered that the supply of water was diminished to 2716hogsheads in the twelve hours. Mr. Smeaton was employed to make some improvements,and he placed a machine in the fifth arch, considerably larger than either of the others.
Ft. In
The diameter of the water-wheel to the extremity of the floats - - 32 0
The diameter of ditto in the rings out and out - - - 27 0
Width of the wheel or length of floats - - - - -15 6
Number of floats twenty-four, width of each - - - - 4 6
Diameter of spur-wheels - - - - - -140
Number of cogs eighty, number in the lantern twenty-three. Diameter of the water-wheel gudgeons 7 inches, and the length of the cylindrical part 7 inches.
When the tide was low the water was forced up by the aid of a fire-engine, as they were
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