+--------------+----------------+-------------+---------------+
|Boiling Point | Altitude Above | Atmospheric | Barometer |
| Degrees | Sea Level | Pressure | Reduced |
| Fahrenheit | Feet | Pounds per | to 32 Degrees |
| | | Square Inch | Inches |
+--------------+----------------+-------------+---------------+
| 184 | 15221 | 8.20 | 16.70 |
| 185 | 14649 | 8.38 | 17.06 |
| 186 | 14075 | 8.57 | 17.45 |
| 187 | 13498 | 8.76 | 17.83 |
| 188 | 12934 | 8.95 | 18.22 |
| 189 | 12367 | 9.14 | 18.61 |
| 190 | 11799 | 9.34 | 19.02 |
| 191 | 11243 | 9.54 | 19.43 |
| 192 | 10685 | 9.74 | 19.85 |
| 193 | 10127 | 9.95 | 20.27 |
| 194 | 9579 | 10.17 | 20.71 |
| 195 | 9031 | 10.39 | 21.15 |
| 196 | 8481 | 10.61 | 21.60 |
| 197 | 7932 | 10.83 | 22.05 |
| 198 | 7381 | 11.06 | 22.52 |
| 199 | 6843 | 11.29 | 22.99 |
| 200 | 6304 | 11.52 | 23.47 |
| 201 | 5764 | 11.76 | 23.95 |
| 202 | 5225 | 12.01 | 24.45 |
| 203 | 4697 | 12.26 | 24.96 |
| 204 | 4169 | 12.51 | 25.48 |
| 205 | 3642 | 12.77 | 26.00 |
| 206 | 3115 | 13.03 | 26.53 |
| 207 | 2589 | 13.30 | 27.08 |
| 208 | 2063 | 13.57 | 27.63 |
| 209 | 1539 | 13.85 | 28.19 |
| 210 | 1025 | 14.13 | 28.76 |
| 211 | 512 | 14.41 | 29.33 |
| 212 | Sea Level | 14.70 | 29.92 |
+--------------+----------------+-------------+---------------+
Sea water contains on an average approximately 3.125 per cent of its
weight of solid matter or a thirty-second part of the weight of the
water and salt held in solution. The approximate composition of this
solid matter will be: sodium chloride 76 per cent, magnesium chloride 10
per cent, magnesium sulphate 6 per cent, calcium sulphate 5 per cent,
calcium carbonate 0.5 per cent, other substances 2.5 per cent.
[Illustration: 7200 Horse-power Installation of Babcock & Wilcox Boilers
and Superheaters at the Capital Traction Co., Washington, D. C.]
The boiling point of water decreases as the altitude above sea level
increases. Table 12 gives the variation in the boiling point with the
altitude.
Water has a greater specific heat or heat-absorbing capacity than any
other known substance (bromine and hydrogen excepted) and its specific
heat is the basis for measurement of the capacity of heat absorption of
all other substances. From the definition, the specific heat of water is
the number of British thermal units required to raise one pound of water
one degree. This specific heat varies with the temperature of the water.
The generally accepted values are given in Table 13, which indicates the
values as determined by Messrs. Marks and Davis and Mr. Peabody.