562 OBSERVATIONS ON THE BAROMETER, 
were advanced and corroborated by the results of 
other Meteorologists. Since that time the period 
has been extended by the addition of twenty-two 
years more ; and it is proposed in this communi- 
cation to give a summary of the observations made 
in the last-mentioned period, and then to incor- 
porate the results with those of the former period, 
so as to obtain averages for the entire of both 
periods. 
If there is any natural tendency in the state of 
the atmosphere to produce rain (or any other 
phenomenon) more at one time of the year than 
another, it will be shewn by the observations of 
a few years. Ten or twelve successive years are 
almost certain to produce a good outline of the 
characteristic features of the year; but it may 
require half a century or more to obtain an exact 
delineation of them, and such as would render 
future observations of little or no avail in pro- 
ducing any sensible alteration. This observation 
is applicable to the fluctuations of the atmosphere 
the Royal Society revised their Meteorological establishment, 
and placed it upon a most respectable footing, since which, 
I believe, they may vie with any public body, or private 
individual, in the regularity and accuracy of their observa- 
tions and tabular results; and, I may add, that I have 
consulted them with pleasure and advantage since on several 
occasions. 
