36 



DYNAMIC METEOROLOGY AND HYDROGRAPHY. 



values do not appear explicitly in Mr. Ekman's paper either, but he has kindly 

 calculated them for us as directly as possible from the compressibilities measured, 

 using the necessary additional data from Amagat and Martin Knudsen. 



Table C. Fundamental Values of a sr ^ of the Specific Volume 

 of Sea- Water under Different Pressures. 



To control the accuracy of tables 8h to 14 h, we can calculate from the tables 

 the specific volume for those values of salinity, temperature, and pressure appearing 

 in tables B and C. It will be seen, then, that all values are found with differences 

 only in exceptional cases exceeding 1 or 2 units in the fifth decimal, these discrep- 

 ancies being easily explained by the possible errors obtained as developed above 

 by the addition of a sum of terms containing small errors. The test thus shows 

 that no error of any importance can have been made, either by the calculation of 

 the formulae of interpolation from the observations or in the calculation of the 

 tables from these formulae. 



29. Tables of the Density of Sea- Water. The density being the reciprocal 

 of the specific volume, tables for the density are easily deduced from those for the 

 specific volume, provided that the same independent variables be retained. For 

 reasons which will become evident later it will be convenient, however, to have 

 the density registered as a function of the dynamical depth instead of as a function 

 of the pressure. Of course there exists no intrinsic physical relation between 

 depth and density. But some measures of precaution being taken, this method of 

 tabulation can be used, thanks to the close relation between depth and pressure in 

 the sea. 



Using the index/? to denote that the dynamic depth appears as an independent 

 variable, we write, corresponding to section 27 (a) and section 27 (d): 





PstD Ps6, 0, D + 



= 6, + r + S sr + Z> + S tD + S .rD 



For the right-hand terms of the last equation we can write expressions corre- 

 sponding to section 27 (c), e being substituted for 8, p for <*, and D for p. 



