158 MR. T. E. THORPE ON THE AMOUNT OF CARBONIC ACID 



for experiment. The capacity of the bottle was 48 15 c.cm. j 

 from this is to be subtracted the volume of air displaced by 

 the baryta-water^ namely 50 c.cm.^ and we have 4765 c.cm. 

 as the amount of air containing 2 "6 milligrammes of car- 

 bonic acid. "We have now, with the temperature and pres- 

 sure of the air, and weight of one litre of carbonic acid at the 

 standard temperature and pressure (namely 1-966 gramme), 

 all the data from which to calculate the proportion in 

 volumes of carbonic acid in 10,000 volumes of air. The 

 calculation stands thus : — 



760 X 2-6 X 286-QX 10,000 ^ ^ . ^ ^^^ 1 n ■ 



-L z, i — ^ = 2'Q4 m 10,000 vols. 01 air. 



753-1 X 273 X 4765 X 1-966 



The fact that the various meteorological changes influ- 

 ence to such a remarkable extent the nature and amount 

 of the gases dissolved in sea- water renders it necessary, in 

 any investigation on the constitution of the atmosphere 

 over the sea, to take particular account of these me- 

 teorological changes. Accordingly the temperature and 

 pressure and degree of humidity of the air, direction and 

 force (estimated, Beaufort's system) of wind, amount (esti- 

 mated, overcast =10) and nature of clouds, and general 

 appearance of the day, together with the temperature of 

 the sea-water and amount of sea-disturbance (i to 9), were 

 noted at the time of each experiment. 



The following Table shows the results of those observa- 

 tions, together with the amount in volumes of the carbonic 

 acid in 10,000 volumes of air. All the experiments which 

 were made are here given. The hours of observation, as 

 before stated, were 4 a.m. and 4 p.m. 



