| Fresh. | Salt. | ||
| 1 | cubic foot at 40° weighs | 62·425 lbs. | 64 lbs. |
| 1 | cubic inch at 40° weighs | ·036,126 lbs. | ·037,037 lbs. |
| 1 | cubic foot at 40° equals | 6·242 gallons | 6·2 gallons. |
| 1 | ton equals | 35·943 cubic ft. | 35 cubic ft. |
| 1 | ton contains at 62° | 224 gallons | 217 gallons. |
VELOCITY OF FALLING FLUIDS.
Falling fluids are governed by the same laws as falling bodies.
Fluid falls 1 foot in a ¼ of a second, 4 feet in ½ of a second, 9 feet in ¾ of a second, and so on.
The velocity of a fluid, flowing through an aperture in the side of a reservoir, is the same that a heavy body would acquire by falling from a height equal to that between the surface of the fluid and the middle of the opening.
The velocity of a fluid flowing out of an aperture is as the square root of the height of the head of the fluid. The theoretical velocity, therefore, in feet per second is as the square root of the product of the space fallen through in feet and 64·333; consequently, for 1 foot it is √64·333 = 8·02 feet. The mean velocity is about 5·4 feet, or 0·673.
PRESSURE OF WATER AT DIFFERENT HEADS.
H. = head in feet. P. = pressure in lbs. per sq. foot. p. = pressure in lbs. per sq. inch.
| H. | P. | p. | H. | P. | p. |
|---|---|---|---|---|---|
| 1 | 62·4 | ·4333 | 9 | 561·6 | 3·9 |
| 1·25 | 78 | ·5416 | 10 | 624 | 4·3333 |
| 1·5 | 93·6 | ·65 | 20 | 1248 | 8·6666 |
| 1·75 | 109·2 | ·7538 | 30 | 1872 | 13 |
| 2 | 124·8 | ·8666 | 40 | 2496 | 17·3333 |
| 3 | 187·2 | 1·3 | 50 | 3120 | 21·6666 |
| 4 | 249·6 | 1·7333 | 60 | 3744 | 26 |
| 5 | 312 | 2·1666 | 70 | 4368 | 30·3333 |
| 6 | 374·4 | 2·6 | 80 | 4992 | 34·6666 |
| 7 | 436·8 | 3·0333 | 90 | 5616 | 39 |
| 8 | 499·2 | 3·4666 |