Dk. T. Thomson on tin Geology and ClimaU of Nict. 195 



Barytcs and lime water made it muddy, and the precipitate was dis- 

 solved in nitric acid, showing the presence of carbonic acid. 



Litmus paper was not altered. Chloride of barium, nitrate of ban 

 ammonia, potash, diacetate of lead, oxalic acid, and oxalate of ammonia 

 occasioned no change, showing the absence of sulphuric acid and lime, 

 and of any uncombinod acid. 



When the waves were high but no wind blowing, which often happens 

 with the Mr.litcn.mean, the balloon was placed about fifty paces from the 

 sea, and the liquid condensed examined by reagents, it was found per- 

 fectly pure, without the smallest trace of common salt or chlorine ; but 

 when the wind blew from the sea to the balloon, placed at the same dis- 

 tance from the beach, the liquid collected exhibited distinct traces of 

 muriatic acid. 



A tube bent in the form of a syphon was got, and a quantity of water, 

 holding nitrate of silver in solution, was put into the bent part of the 

 tube. One of the extremities of the tube was open, the other was luted 

 into the mouth of a very large glass vessel, having a stop cock, and filled 

 with water. The stop cock being opened, the water ran out, and its place 

 was supplied by air, which made its way by the syphon tube, and conse- 

 quently passed through the nitrate of silver solution. When the large 

 vessel was exhausted of water it was filled again, and the experiment 

 renewed. Air in this way was made to pass through the nitrate of silver 

 solution for six hours. In this way a prodigious quantity of air was made 

 to pass through a small quantity of nitrate of silver solution. This expe- 

 riment was tried when the sea was calm and no wind blowing, in a boat 

 at some little distance from the shore, and a few paces from the beach. 

 No precipitate appeared, nor was there the least symptom of the presence 

 of common salt. But when the sea was agitated and a wind blew from 

 it, the solution became muddy, and chloride of silver was precipitated, 

 iinlieating the presence of common salt. 



These experiments leave no doubt that the common salt, occasionally 

 observed in the atmosphere of the sea, is not dissolved in that atmosphere, 

 but proceeds from a little sea water mechanically suspended, and which 

 of course is speedily deposited. In calm weather the sea atmosphere is 

 quite free from salts ; it is, therefore, not in the least injurious to invalids, 

 as some medical men have supposed it to be. 



Vjth November, 1847. — Tlie Vice-Pki >im at in the Chair. 



The Librarian intimated that the library had been valued and recom- 

 mended to be insured for £500, and also that the first thirty-one volumes 

 of the Medianies' Magazine had been purchased. A minute of Council 

 was read re< ommending the Society to abolish the office of Assistant- 

 Secretary, ami to el. .1 two Secretaries, and that Article I. of the Rules 



