488 Meteorology. 
In the above table, the means for each year 
are placed on the right, and the means for 
each month of the year et the bottom; by 
which we are enabled to judge whether any 
particular season or month of the year is 
more liable than another, to have an accu- 
mulation or deficiency of the atmosphere.— 
It is evidently only from a long series of 
years, that we are entitled to draw any con- 
clusions of this kind. 
From an inspection of the above table, it 
is obvious that the barometer appears to be 
higher in the summer than in the winter 
months ; but this must arise in part at least 
from the expansion of mercury by heat; a 
correction therefore is necessary on that ac- 
count, and the following table of temperature 
for each month in the year, with the known 
expansion of mercury, enables us to apply 
the proper correction. The correction being 
applied accordingly, we have the subjoined 
corrected heights for each month, On look- 
ing over this corrected column, we still per- 
ceive the mercury higher in the summer 
months than in the winter. The heights for 
March, April, May, June, July, August and 
September, are all at or above the mean; and 
June in particular, possesses a marked supe- 
riority of ~, of an inch above the mean. — 
