2, 5 8 Z)r. Dobson’s Obfervations on 
vapours, and the whole country involved in what they 
call Gamas , or thick fogs (,J . 
It is not necefiary to point out the caufes which thus 
difpofe the air to depofite its diflblved water ; nor to con* 
fider with what bodies air hath a Stronger affinity than 
with water; neither to inquire how far the electrical fluid 
is engaged in the procefs. It is fufficient to obferve, that fo 
long as thefe caufes have a general aCtion on the air, they 
diminifh its power of folution,and give a damp and foggy 
ftate of the atmofphere; that when they operate fora con- 
fiderable proportion of the year, they produce a moift 
climate ; and that when they more generally do not, and 
the air retains its moifture in a ftate of perfedt folution, 
the climate is dry. Confequently, that the moifture or 
drynefs of a climate, do not fo much depend upon the 
abfolute quantity of water which is contained in the air, as 
upon the air being in a ftate of perfect or imperfeCt folu- 
tion. During long continued fummer droughts, a very 
large proportion of water is diffolved in the air; notwith- 
standing this, the air is ftill dry, and continues to be fo as 
but as the water remains in a- ftate of perfect folution; 
long no fooner are the powers of folution diminished, 
than what was before a dry, now becomes a moift climate. 
(i) D’Ulloa’s Voyage to South America, vol. II. p. 69. 
In 
