+----------------------+--------------------------------+ | MARKS AND DAVIS | PEABODY | | From Values of | From Values of | | Barnes and Dieterici | Barnes and Regnault | +-----------+----------+---------------------+----------+ |Temperature| Specific | Temperature | Specific | +-----------+ Heat +----------+----------+ Heat | | Degrees | | Degrees | Degrees | | |Fahrenheit | |Centigrade|Fahrenheit| | +-----------+----------+----------+----------+----------+ | 30 | 1.0098 | 0 | 32 | 1.0094 | | 40 | 1.0045 | 5 | 41 | 1.0053 | | 50 | 1.0012 | 10 | 50 | 1.0023 | | 55 | 1.0000 | 15 | 59 | 1.0003 | | 60 | 0.9990 | 16.11 | 61 | 1.0000 | | 70 | 0.9977 | 20 | 68 | 0.9990 | | 80 | 0.9970 | 25 | 77 | 0.9981 | | 90 | 0.9967 | 30 | 86 | 0.9976 | | 100 | 0.9967 | 35 | 95 | 0.9974 | | 110 | 0.9970 | 40 | 104 | 0.9974 | | 120 | 0.9974 | 45 | 113 | 0.9976 | | 130 | 0.9979 | 50 | 122 | 0.9980 | | 140 | 0.9986 | 55 | 131 | 0.9985 | | 150 | 0.9994 | 60 | 140 | 0.9994 | | 160 | 1.0002 | 65 | 149 | 1.0004 | | 170 | 1.0010 | 70 | 158 | 1.0015 | | 180 | 1.0019 | 75 | 167 | 1.0028 | | 190 | 1.0029 | 80 | 176 | 1.0042 | | 200 | 1.0039 | 85 | 185 | 1.0056 | | 210 | 1.0052 | 90 | 194 | 1.0071 | | 220 | 1.007 | 95 | 203 | 1.0086 | | 230 | 1.009 | 100 | 212 | 1.0101 | +-----------+----------+----------+----------+----------+ 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. BOILER FEED WATER