December 2*4° above ; January, 1838, was 6'8° below, and 
February 5*3° below tbe average temperature. 
Cold winters succeeding a warm November appear to be 
very feu in number, and generally these winters are pre- 
ceded by a November not much above the average, as in 
1783, 1794, and 1799, in which years the mean temperature 
of November was only 05°, 0-9°, and 0.5° above the average 
respectively. 
November, 1822, and 1846, were the only two Novembers 
much above the average which were followed by a cold 
period immediately afterwards. 
A Paper was read entitled “Note on the amount oi 
Carbonic Acid contained in the air of Manchester,” by 
Henry E. Roscoe, B.A., Ph.D., F.R.S. 
Determinations of the quantity of carbonic acid contained 
in the air of towns have been made by Dr. Angus Smith in 
Manchester, and by Lewry in Paris; but as the experi- 
ments hitherto made upon the subject are few in number, 
and have yielded somewhat remarkable results, it appeared 
of interest to carry out a scries of determinations of atmo- 
spheric carbonic acid, made by unimpeachable methods, 
and extending for a considerable time, under wide variation 
of weather. 
The analytical method employed was the excellent volu- 
metric one proposed by Pettenkofer, and this was checked in 
several instances by simultaneous weight determinations 
made by absorption in caustic potash. The close agreement 
of the results in experiments Nos. 8 and 9; Nos. 15 and 16; 
Nos. 42 and 43 ; and Nos. 45 and 46, in the accompanying 
table, gives proof of the reliability of the methods. The 
experiments were made under my supervision by Mr. Arthur 
Me. Dougall. 
In the case of the weight analyses, a given volume (not 
less than 35 litres) of air was drawn in the first place over 
