cloud; nie the Sooner apealiainate is wanting, what- 
overs may be the cause. I state facts from repeated and uniform ob- 
servation ; but I dare not in this instance undertake to assign the 
cause of their existence. 
The foregoing facts were confirmed by the phenomenon, which 
took place after the season was so far advanced, that the dew om 
the windows would Beets except one night, when some frost 
appeared on the glass, notwithstanding the sky was somewhat over- 
cast. In all other respects the phenomena were the same. Wher- 
ever the glass was exposed to the action of the external air, though 
for a breadth of three inches only, there the inside of the glass was 
covered with a thin frost. But wherever the outside shutters shield- 
ed the glass, there was no frost or dew. 
From these facts one is naturally led to conclude, that condensa- 
tion is the principal, if net the sole cause of dew. If condensation 
is the sole cause of dew, then it depends on the same principle as dis- 
tillation, or the condensation of vapor in the worm of a still; as also — 
on ‘the same principle, with the dew on the outside of vessels, filled 
with cold water in a hot summer’s day. If so, the inquiry is, whether 
acertain fied degree of cold, in the air or object condensing, be nec- 
sary to form dew? Or whether the degree of cold be only compara- 
tive, that is, in a certain proportion ‘to that‘of the vapor condensed? 
From sueh observations, as bu neocon. able: to. make, baecuaingy 
to believe the degree of cold comparative. 
The water in the enirni xabeiofe common distilleries is taken’ foes 
rivers, and not from wells. . This water is considerably warmed in the 
tubs, yet is cold enough to condense the vapor, that rises from the 
boiling fluid in the stills. But the same degree of cold would by no 
means condense'the vapor of the atmosphere in the hottest summer’s 
day. Yet cold water, fresh from a deep well: or spring, will ;con- 
dense it rapidly. 
