THERMOMETER AND RAIN. 563 
in weight, as shewn by the Barometer, and to the 
temperature of the atmosphere, as well as the 
quantity of rain, and to the other meteoric phe- 
nomena. 
1. Or tHE BAROMETER. 
Experience proves that the weight or pressure 
of the atmosphere on the earth’s surface is con- 
tinually varying from winds and other causes; 
and there is reason to believe that changes of 
weather are in some way connected with these 
fluctuations in the weight of the atmosphere, and 
hence the utility of Barometrical Observations. 
In the Torrid Zone the variation is little ; in 
the Temperate Zone the variation is much greater ; 
it increases with the latitude, and is about double 
in winter to what it is in summer, and it is pro- 
bably still greater in the Frigid Zones. 
Many people imagine that the variations are 
local—that the Barometers may rise in one town, 
and fall in another neighbouring town at the same 
time. This is not the case; the variations take 
place in London, Penzance, Dublin and Edin- 
burgh, at the same time, and to the same amount 
nearly. 
