CARBON DIOXIDE OF THE OCEAN 611 
temperature counteracts within 2 per cent. to 4 per cent. of the 
total CO, as second equivalent, the effect of the decrease in 
the partial pressure. 
These estimates are of course founded on too small an experi- 
mental basis, and the data themselves show too great disagree- 
ments to conclude that the decrease of the dissociation due to 
the falling temperature, counteracts exactly within 2 per cent. to 
4 per cent. of the second equivalent of CO,, the increase due to 
the diminishing partial pressure ; but we may conclude ‘hat they 
ave probably of the same order of magnitude, or that a—d is com- 
parable in length with c—d or c-e. 
All this however, is under the proposition of Professor 
Arrhenius, that a 5° lowering of the average climate of the 
temperate regions will bring on glaciation. We have still to con- 
sider the effect of the waters of the equatorial region on the one 
hand, and those of the higher latitudes on the other. 
The average temperatures of the ocean waters at the surf 
line between 45° north and south latitudes, are as follows :? 
For the belt between 15° north latitude, and 15° south latitude, 26 degrees 
centigrade. 
For the belts between 15°-30° north latitude, and 15°—30° south latitude, 
21 degrees centigrade. 
For the belts between 30°-45° north latitude, and 30°-45° south latitude, 
17 degrees centigrade. 
The average temperature between 45° north latitude and Ate 
south latitude, at the depth of 1500 fathoms is between 2°—3° 
centigrade. 
Professor Ditmat has found that at temperatures between 
18°—21° C. that the dissociation tension of the bicarbonates of 
the sea water is five ten-thousandths of an atmosphere. On the 
other hand, at temperatures near zero, the dissociation does not 
take place, and the tension of course becomes nil. (See table 
above. ) | 
The partial pressure of the CO, in the atmosphere at the 
present time is about three ten-thousandths. Therefore, he con- 
‘Compiled from tables Challenger’s Rep., Vol. I, Table VI, at end of volume. 
