20 Mr. Boase onthe Differences in the Statements of [Juny, 
to the other. The first of these two, or No. 2, is 150 yards dis- 
tant from the Museum, and 90 feet above the sea. No. 3 is 
about 500 yards from both the former, and 70 feet above the 
level uf the sea. In these two, viz. No. 2 and No.3, the quan- 
tity of rain was on the whole equal, only varying occasionally 
in a small degree above or below each other; but the difference 
between them and No. 1 is very great, viz. above 3 to 2, the 
result of 12 months being, in No. 1, 30°475 inches ; and in No. 2 
and No.3, 46:080 inches. 
The ratio varied considerably in several months, as for 
instance, the total of 
No, 2 and 3, No. 1. 
Aug. 1821, was in. 4-470 .... 4°000 being nearly as 9to 8 
September i. 2 4 BDOM i SAGO 9 6 
Getober. 1. FIO) OMB SoG 11 fy 
November’. 228 245° 170) Se oalo 10 6 
December. ...... 9-500 .... 6°480 Toy 40s 
These months were unusually wet, and the three last remarkably 
stormy. 
Having observed that the difference between the first and the 
other guages varied with the more or Jess wind, its velocity has 
been registered from observation ; but not having an accurate 
anemometer, we cannot yet offer any certain conclusion further 
than this, that the difference in the quantity of rain received in 
a guage placed on the top of a building and one at a level with 
the surface of the ground, is, for some reason or other, propor- 
tioned to the velocity of the wind; and that the average excess 
of the lower guage is much greater than can be attributed to any 
or all the causes hitherto assigned. For admitting all that can 
be due to the difference of the sine of the angle of inclination at 
which the falling drops may reach the earth; and also all that 
could accrue from a continued condensation of aqueous vapour 
between the altitude of the upper guage and the surface of the 
ground, yet the aggregate of both would, in an elevation of only 
45 feet, be trivial, in comparison of the enormous difference 
found every month, and on the average of the whole year. 
The facts obtained do not yet, perhaps, warrant the positive 
conclusion, and we, therefore, offer it only as a conjecture that 
the aforesaid difference is owing chiefly to the whirl or eddy 
occasioned by the recoil of the gusts of wind striking on the 
sides of the building—an effect very visible in the disturbance 
of smoke issuing from chimneys during a high wind. 
Since the discovery of the self-registering thermometer, and 
the consequent notation of the daily maximum and minimum of 
temperature, it has been found that the annual mean heat of the 
north and south of Great Britain is much more equal than was 
supposed ; and it seems probable that the annual mean of the 
