Chemical Analysis of the Atmosphere. 287 
~ratus might be erected of large dimensions, by using for example, a 
hogshead, and causing the air to flow during whole days through dif- 
ferent reagents. ‘To experimenters residing near the Ocean this 
method may be specially recommended. It is known that some tri- 
als, made within a few years, of the air over the Baltic Sea, have fur- 
nished very curious results which it would be interesting to follow up. 
- But in a variety of other circumstances such researches may be 
very useful. Ihave endeavored to subject our autumnal fog, the pe- 
culiar odor of which is known to all, to the action of several rea- 
gents. I have passed air, loaded with this fog, through nitrate of sil- 
ver, and chloride of silver dissolved in caustic ammonia. Nothing 
positive was obtained. In the last case a precipitate was produced 
which speedily assumed the color of chloride of silver exposed for 
some time to the light, and which was found to be in reality that salt, 
doubtless precipitated from its ammoniacal solution by the carbonic 
acid introduced with the atmosphere. 
_T advert to these incomplete trials only to suggest methods which 
I think may be followed in investigations of this nature.—Bib. Univ. 
Mars, 1832. 
‘Berne, March 27th, 1832. 
