CONTAINED IN THE AIR ABOVE THE IRISH SEA. 151 



lected over the Baltic, about half a mile from the coast at 

 Doberam, contained so little carbonic acid, that baryta- 

 water was scarcely rendered tui'bid by it. A repetition of 

 the experiment made in 1822 by the same observer in the 

 Channel, two leagues from Dieppe, by emptying a bottle 

 of distilled water and testing the air with baryta solution, 

 gave a perfectly similar result. 



Kriiger, at Rostock (Schw. xxxv. 379), also observed that 

 the air did not render lime-water turbid when the wind 

 came from the north, the direction of the Baltic, but that 

 a considerable turbidity was produced by a wind blowing 

 from the opposite direction, namely from the land. 



Theodore de Saussure (Ann. de Chimie et de Phys. xliv. 

 1830) noticed that the air collected near the surface of 

 Lake Seman generally contained less carbonic acid than air 

 taken at Chambeisy, half a league distant. 



The difference, however, is but slight : the means of 

 eighteen determinations, made at different seasons of the 

 year and at various times of the day, gave for the air of the 

 lake 4"39, for the air of the land 4*60 in 10,000 volumes of 

 air, or as 95 to 100. 



Watson (Brit. Assoc. Reports, iv. 1835, and Journ. fiir 

 Prakt. Chemie, iii. 75, 1835) likewise found from deter- 

 minations made near Bolton, that winds from the seaward 

 contained less carbonic acid than when blowing from the 

 land. Thus, on Nov. 6th, 1833, at 2 p.m., after much rain, 

 and with a very strong west wind, the air contained 3*614 

 vols, in, 10,000 of air, and on Dec. 6th, in precisely similar 

 circumstances as to wind and rain, exactly the same amount. 

 Southerly and easterly winds from the land ga^^e numbers 

 varying from 4"i96 to 4*730 in 10,000 vols, of air. These 

 determinations were made by absorbing the carbonic acid 

 in a known volume of air by means of a measured quantity 

 of lime-water of known strength. After the expiration of 

 a week, during which the vessel was frequently agitated, 



