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XIII. Obfervations on the Annual Evaporation at Liver- 
pool in Lancalhire; and on Evaporation considered as a 
! Eejl of the Moifture or Drynefs of the Atmofphere. By 
Dr. Dobfon of Liverpool. Communicated by John 
Fothergill, M. D. F. R. S. 
Read Feb. 13, f g *HE quantity of rain which falls during 
the courfe of the year, is a very un- 
certain teft of the moifture or drynefs of any particular 
ffeafon, fituation, or climate. There may be little or even 
no rain, and yet the air be conftantly damp and foggy ; 
or there may be heavy rains, with a comparatively dry 
ftate of the atmofphere. The fame depth of rain will 
likewife produce different effects on the air, according as 
it falls upon a flat or hilly country ; for large quantities 
foon quit the hills or high grounds, while fmaller quan- 
tities have more falling and powerful effects on a flat 
country. Much alfo depends upon the nature of the 
foil, whether clay or fand, whether firm and compact, or 
loofe and fpungy. 
Is not evaporation therefore a more accurate teft of 
the moifture or drynefs of the atmofphere, than the 
quantity of rain ?• 
It 
