36 



Papers from the Department of Marine Biology. 



By means of the conversion table (fig. 6) it is possible to determine the 

 C0 2 tension of sea-water from the temperature and P H as read by means 

 of the standard tubes and colorimeter described on pages 44-46. The 



8.4 PK 



4567S91 

 xlO- 



2 3 456T891 



ion concentra tion 



4 5 6 7 8 910 



FIG. 6. Conversion table for finding the CO* tension of sea-water from theP H and the tempera- 

 ture. On the ordinate is measured the logarithm of the COs tension in ten-thousandths of an 

 atmosphere. On the abscissa is measured the P n , with a scale below for converting it into the 

 normality of H ions. The four curves are for 30 D , 20, 10, and 0, the last of which has been 

 extrapolated. The crosses mark the determinations of Henderson and Cohn by the colori- 

 metric method at 20. 



tension is of first importance in the respiration of marine organisms. 

 The rate of elimination of CC>2 by animals and its absorption by plants 

 in the sunlight is directly proportional to the difference in C02 tension 

 just outside and inside of the respiratory surfaces. Life in the sea is 



