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.
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
In consequence of this variation in specific heat, the variation in the heat of the liquid of the water at different temperatures is not a constant. [Table 22] [13] gives the heat of the liquid in a pound of water at temperatures ranging from 32 to 340 degrees Fahrenheit.
The specific heat of ice at 32 degrees is 0.463. The specific heat of saturated steam (ice and saturated steam representing the other forms in which water may exist), is something that is difficult to define in any way which will not be misleading. When no liquid is present the specific heat of saturated steam is negative. [14] The use of the value of the specific heat of steam is practically limited to instances where superheat is present, and the specific heat of superheated steam is covered later in the book.
FOOTNOTES
[ [12] ] Marks and Davis