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+—————+———————+—————+ |Temperature|Relative Volume|Weight per| | Degrees | Water at 39.2 |Cubic Foot| | Fahrenheit| Degrees = 1 | Pounds | +—————+———————+—————+ | 32 | 1.000176 | 62.42 | | 39.2 | 1.000000 | 62.43 | | 40 | 1.000004 | 62.43 | | 50 | 1.00027 | 62.42 | | 60 | 1.00096 | 62.37 | | 70 | 1.00201 | 62.30 | | 80 | 1.00338 | 62.22 | | 90 | 1.00504 | 62.11 | | 100 | 1.00698 | 62.00 | | 110 | 1.00915 | 61.86 | | 120 | 1.01157 | 61.71 | | 130 | 1.01420 | 61.55 | | 140 | 1.01705 | 61.38 | | 150 | 1.02011 | 61.20 | | 160 | 1.02337 | 61.00 | | 170 | 1.02682 | 60.80 | | 180 | 1.03047 | 60.58 | | 190 | 1.03431 | 60.36 | | 200 | 1.03835 | 60.12 | | 210 | 1.04256 | 59.88 | | 212 | 1.04343 | 59.83 | | 220 | 1.0469 | 59.63 | | 230 | 1.0515 | 59.37 | | 240 | 1.0562 | 59.11 | | 250 | 1.0611 | 58.83 | | 260 | 1.0662 | 58.55 | | 270 | 1.0715 | 58.26 | | 280 | 1.0771 | 57.96 | | 290 | 1.0830 | 57.65 | | 300 | 1.0890 | 57.33 | | 310 | 1.0953 | 57.00 | | 320 | 1.1019 | 56.66 | | 330 | 1.1088 | 56.30 | | 340 | 1.1160 | 55.94 | | 350 | 1.1235 | 55.57 | | 360 | 1.1313 | 55.18 | | 370 | 1.1396 | 54.78 | | 380 | 1.1483 | 54.36 | | 390 | 1.1573 | 53.94 | | 400 | 1.167 | 53.5 | | 410 | 1.177 | 53.0 | | 420 | 1.187 | 52.6 | | 430 | 1.197 | 52.2 | | 440 | 1.208 | 51.7 | | 450 | 1.220 | 51.2 | | 460 | 1.232 | 50.7 | | 470 | 1.244 | 50.2 | | 480 | 1.256 | 49.7 | | 490 | 1.269 | 49.2 | | 500 | 1.283 | 48.7 | | 510 | 1.297 | 48.1 | | 520 | 1.312 | 47.6 | | 530 | 1.329 | 47.0 | | 540 | 1.35 | 46.3 | | 550 | 1.37 | 45.6 | | 560 | 1.39 | 44.9 | +—————+———————+—————+

Water is but slightly compressible and for all practical purposes may be considered non-compressible. The coefficient of compressibility ranges from 0.000040 to 0.000051 per atmosphere at ordinary temperatures, this coefficient decreasing as the temperature increases.

Table 11 gives the weight in vacuo and the relative volume of a cubic foot of distilled water at various temperatures.

The weight of water at the standard temperature being taken as 62.355 pounds per cubic foot, the pressure exerted by the column of water of any stated height, and conversely the height of any column required to produce a stated pressure, may be computed as follows:

The pressure in pounds per square foot = 62.355 × height of column in feet.

The pressure in pounds per square inch = 0.433 × height of column in feet.

Height of column in feet = pressure in pounds per square foot ÷ 62.355.

Height of column in feet = pressure in pounds per square inch ÷ 0.433.

Height of column in inches = pressure in pounds per square inch × 27.71.

Height of column in inches = pressure in ounces per square inch × 1.73.

By a change in the weights given above, the pressure exerted and height of column may be computed for temperatures other than 62 degrees.

A pressure of one pound per square inch is exerted by a column of water 2.3093 feet or 27.71 inches high at 62 degrees Fahrenheit.

Water in its natural state is never found absolutely pure. In solvent power water has a greater range than any other liquid. For common salt, this is approximately a constant at all temperatures, while with such impurities as magnesium and sodium sulphates, this solvent power increases with an increase in temperature.