268 Meteorological Observations. 
The inequalities of pressure in the opposite seasons at Canton 
will appear more strongly, if we omit the months of April and 
October, which have nearly the mean pressure of the year. We 
have then a mean for the five months of the northerly monsoon 
or winter period, of 30.178 inches: the mean for January being 
as high as 30.24 inches. But for the five months of the south- 
erly monsoon we find a mean of only 29.836 inches ; and the 
mean of July and August is still lower, being 29.80 inches. We 
have thus an inequality of 0.342 inch: more than one third of 
‘an inch, for the average period of the two monsoons; while as 
between January and July and August, in the opposite monsoons, 
we have the still greater difference of 0.440 inch; approaching 
to half an inch of the barometric column. I have alluded to this 
extraordinary inequality of barometric pressure, on a former 0¢- 
In regard to the prevalent winds at Canton, and their state of 
humidity, we perceive that the greater number of rainy days and 
the greatest depression of the barometer, accord nearly with the 
period in which the southerly monsoon most steadily prevails. 
The smallest number of rainy days and greatest atmospheric 
pressure accord equally with the prevalence of the northerly 
monsoon. 
At New York, and also at Newfoundland, the tendency of the 
winds and the distribution of rain, throughout the year, is proba 
bly more uniform than at Canton; but the region about New- 
foundland is believed to be somewhat remarkable for its humidity, 
particularly in the summer months ; while, as we have seen, in 
the latter season the barometer maintains more than its average 
elevation. 
In view of all the facts presented, therefore, there appears 3° 
good reason to ascribe to hygrometric considerations, in any CO” 
siderable degree, the great differences in the equality of atmos 
pheric distribution which are here brought to our notice. 
New York, December 3d, 1839. 
* See this Journal, Vol. xxxiu, p. 264. 
