70 
INCHES 
The largest amount of rain fell in 1792, and was 55*250 
The least amount of rain fell in 1826, and was ... 24*910 
Mr. Curtis pointed out that the rain which fell from 1793 
to 1814 was below the average of the 64 years, from 1815 to 
1852 it was above, and from 1853 to the present time it has 
again fallen below, from which he infers we have entered into 
a low series, and that, consequently, we may for some time 
expect it to remain below, though there will doubtless be 
some few intermixed above it. This variation was clearly 
seen on a chart he exhihited. He also pointed out the 
following differences, as seen in his tables. 
From 1795 to 1814, inclusive, the mean of the 20 years is 
33*044 inches; from 1815 to 1836, inclusive, the mean of the 
22 years 38*161 ; from 1837 to 1852, inclusive, the mean of 
the 16 years is 36*328; while from 1853 to 1857j inclusive, 
the mean of the 5 years is only 31*371, showing the correct- 
ness of Dr. Dalton’s remarks, as to the importance of a long 
continued series of observations, to obtain a satisfactory table 
of the mean quantity either for each month or the whole year. 
Dr. Joule having taken the Chair, a Paper was read by 
the President, entitled “ Notice of some Experimental 
Apparatus for Determining the Density of Steam at all Tem- 
peratures.” 
The Author proposed to give a brief sketch of some 
apparatus w'hich has been recently constructed, in order to 
ascertain the density of steam at various temperatures ; and 
thus, to correct or verify some theoretical speculations in 
regard to the relation between the specific volume and tem- 
perature of steam and other vapours. The experiments are 
being conducted, it is believed, on an entirely novel and 
original principle, applicable at any temperature and pressure 
capable of being sustained by glass. 
For a perfect gas, the law which regulates the relation 
between temperature and volume is known as Gay Lussac s, 
or Dalton’s law, and is expressed in the equation 
