there is a good flow of water with a moderate fall, to raise a small portion of that flow to a greater height than the fall. About 10 gallons of water must pass through the ram for every gallon raised, and the elevation to which water can be raised by the ram is in proportion to the fall obtainable, generally equal to ten times the fall.

The following are the usual proportions of the supply pipes and delivery pipes to the number of gallons.

The efficiency of hydraulic rams rapidly decreases, as the height to which the water is to be raised increases above the fall, as will be seen from the following table.

TABLE 8.-EFFICIENCY OF HYDRAULIC RAMS.

Number of times the height to which the Water is to be raised contains the fall . Efficiency per cent.

4 5 6 7 8 9 10 11 12 13 14 15 16 18 19 20 25 75 7268 62 5753 48 43 38 35 32 28 23 1715 12

Speed of Pumps.-The greatest speed at which water will flow through a suction-pipe, is 500 feet per minute; but, in practice, water should not flow through a suction-pipe at a greater speed than 200 feet per minute to ensure the pump-barrel being properly filled at each stroke, that is 200 feet of the suction-pipe should hold as much water as the pump will deliver per minute, and the pump should work at such a speed that it will deliver per minute the quantity of water contained in 200 feet of its suction-pipe. For pumping engines, the most economical speed is from 4 to 5 strokes per minute, the length of stroke being generally 8 feet for small pumping engines; 10 feet for medium size; and 12 feet for large sizes. Proportion of Cocks.-D the internal diameter of pipe. Square of plug D x 5. Height of square = Dx 5. Length of handle = D × 6. Diameter of plug at the centre = D × 125. Length of taper part of plug = D x 2 to 2 for solid bottom gland cocks, and D x 3 to 31 for plugs with screw bottom. Height of water-way in plug Dx 125. Width of water-way in plug = D x 7. Taper of plug on each side = 1 inch in 9 inches for small cocks, and 1 inch in 12 inches for large cocks.

=

=

H

TABLE 10.-SHEWING THE QUANTITY OF WATER DISCHARGED PER MINUTE BY SINGLE-, DOUBLE-, AND TREBLE-BARREL PUMPS AT VARIOUS SPEEDS, EXCLUSIVE OF SLIP.

Water Supply.-15 gallons per head per day, for domestic purposes; 10 gallons per head per day, for manufacturing purposes; 5 gallons per actual horse-power per hour, for feeding boilers; 5 gallons per nominal horse-power per minute, for injection water for condensing engines.

TABLE 11-SHEWING THE QUANTITY OF WATER IN GALLONS DELIVERED AT EACH STROKE OF A PUMP.

022

035

Inches. Gall. Gall. Gall. Gall. Gall. Gall. Gall. Gall. Gall. Gall. Gall. Gall.
008 011 014 017 02
013017 021 026 03

Gall.

Gall.

Gall. Gall. Gall. Gall.

Gall. Gall. Gall.

025

04

028 031 034 04
044 048

*045

'05

*068 *085

*102

053

061

*07

*08

*106

132

160

019 025 031 038 044

05

057 063 07

076 '09

ΟΙ

*114

153 *191

230

026 034 042 052 06

07

078 086 095

104 '121 138

156

*208

*260

312

034 044 055 067 08

*09

113 124

135 158 181

*20

*272

*340 *407

2}

043 056 070 086 10

'II

13

143 157

172
'17 '19 '21 '24 $28
*25
*28
'30 35 4
*24 *27 '31 *34
*38 '41 *48
27 31 36 *40 *45 '50 '54 *63
34 4 45 '51 *57 *63 *68 .8 '91 ΙΟ
49 56 '63 '71
.85
'77
113 I'27 1'70 2.12 2:55
.81 '92 I'02 I'12 1'22 1.42 163 1.83 2:44
3'05
125 138 152 1.66 194 2.22 2:50 3:33 4'16
1.81 2'0 217 2:53 2.90 3:26 4'35 5943 6:52
252 275 321 3.67 413 5'50 6.88 8.26
340 3'96 4'53 5'09 6.80 8.50 10'20
8:22 10:27 12:33
979 12:23 1468
11:49 14:36 17:23

27:19 33'98

40'79

47 59

54 39

61 18 6798

81:58

246

3290 4113

49:36

57 58

65.81

7403 82:25

98-72

29.3

39 16

4895

58 74

68 53

78 32

88 10 97 90

117:47

The Strength of Steam-Cylinders, Water-Cylinders, pipes, and tubes of all kinds subject to internal pressure, may be found by the following rules. In the case of steam cylinders, allowance must be made for wear and for boring and re-boring.

Thickness of Metal for Pipes.-Rule: Multiply the working pressure inside the pipe in lbs. per square inch, by the internal radius of the pipe in inches, and divide the product by the safe working tension given in the table below for the material of which the pipe is made, to which quotient add the constant number C., and the result will be the thickness of the pipe in inches. The value of C. ranges from 13 to 10, according to circumstances, for cast-iron pipes for water, C. is 3; and for steampipes 5, the working pressure in each case being taken at 133 lbs. per square inch, to allow for contingencies in making stock sizes of pipes. Example required the thickness of a cast-iron pipe 8 inches in diameter, suitable for a working head of 300 feet water-pressure, or 133 lbs. per 133 lbs. pressure × 4 (radius of pipe) square inch, then = 2500 safe working tension of cast-iron =512 inches thickness.

=212 + 3

Bursting Pressure of Pipes.-Rule: Multiply the bursting tension in lbs. per square inch-given in the table below-of the metal of which the pipe is made, by the thickness of metal in inches, and divide the product by the internal radius of the pipe in inches, the result will be the bursting pressure in lbs. per square inch,

Example, required the bursting pressure of the 8-inch pipe given in the 15000 bursting tension X 512 thickness of pipe last example, then,

1920 lbs. bursting pressure.

4 inches internal radius of pipe

TABLE 12.-STRENGTH OF MATERIALS FOR PIPES FOR THE ABOVE RULES.