SECT. IJ 



PHYSICAL PKOPERTIES OF SEA-WATER 



13 



specific heat with temperature and sahnity is shown in Fig. 2. Not only is the 

 variation of specific heat of sea-water different from that of pure water, but 

 absohite vahies differ appreciably from those given by Thoulet and Chevallier 

 (Fig. 3). 



Fig. 2. Specific heat of sea-water, Cp, in absolute Joules per gram per degree Celsius as a 

 function of temperature (°C) and salinity (%o) at atmospheric pressure. 



■Cox ond Smith (1959) 

 Thoulet and Chevallier (1889) 



Fig. 3. A comparison of values of specific heat of sea-water, Cp, at 17.5°C and atmospheric 

 pressure as determined by Thoulet and Chevallier (1889) and Cox and Smith (1959). 



From an analysis of their determinations. Cox and Smith proposed the 

 formula 



Cp = r/(i?') - 5.075 X 10-3^ -1.4 X 10-5,S2 (29) 



for the specific heat at constant pressure, where Cp is the specific heat in abso- 

 lute Joules per gram per degree Celsius and Cp^{d'') is the specific heat of pure 

 water at temperature &' . The value of c^o appropriate to (29) is given by the 

 pure -water formula at an elevated temperature &' , where 



^' = ^ + 0.7/S + 0.0175*^2 (30) 



Cox and Smith did not give a formula for Cp^{&). A simple and accurate 



