SECT, 1] 



THE FLOW OF HEAT THROUGH THE FLOOR OF THE OCEAN 



225 



is sufficient, ps may be taken as 2.5 g/cm^. If the water content is determined by 

 drying, it is the content of j)ure water and not sea-water that is given by w ; 

 ptv should, therefore, be taken as 1 g/cm^, and 



p-i = 0.40 + 0.60m;. 



(5) 



Similarly, the specific heat of a sediment may be calculated from the specific 

 heats of its constituents ; though there is a small discrepancy between the 

 specific heat of sea-water and that calculated for a mixture of salt and pure 

 w^ater (Cox and Smith, 1959), it seems sufficient to take the specific heat of the 

 solids as 0.18 cal/g °C and of the liquid removed on drying as 1.00 cal/g °C. The 

 specific heat of the sediment is then given by 



a = 0.18 + 0.82m;. 



(6) 



Typical values of the thermal properties of ocean-bottom sediment as a func- 

 tion of w^ater content are given in Table I. These are calculated from the ex- 

 pressions (4), (5) and (6) above. Ratcliff"e (1960) gives nomograms connecting 

 density, water content and conductivity. 



^ \A0 



160 



180 



160 



Fig. 6. Heat-flow measurements in the western Pacific. 



