Meteorological Obfervations.. 5O5e 
for according to an ingenious Italian philjofos 
pher, nearly double as much water evaporates 
from an open veffel, as: falls into. it in the form 
of rain.* Now, though an evaporation gage may: 
afcertain the quantity of water which evaporates 
from an open veflel of a given aperture, yet it 
will by no mean afcertain the ratio between | the 
quantity evaporated from the internal furface 
ef the funnel, and the whole quantity received 
by the gage. Mr. Gough propofes an ingenious 
method of determining this point by means ‘of 
_ two contiguous gages. For, let 4 and a =the 
areas of the apertures of the two gages, B and 4 == 
the curve furfaces of their funnels, S and s==the 
quantities of water collected by them in a given 
time in grains, X and x = the quantities loft 
by evaporation. Then S 4+ X and s +x being 
the quantities received by the gages, we have 
Aza: S4+Xis4+x, andx= sets iriey, 
but fince the quantities evaporated in the fame 
time are as thofe furfaces, B:4:: X: x, and x 
== aes = ioe + e% hence X = 
) © c,0.6)@) iu Pract 
* Vide Opere del Padre Cisvaak! Baptifta da St. Mar. 
tino, Vol, I, Art, 4. 
