r I3S ] 
And that they will afcend proportionally higher, as 
the furrounding fluid is proportionally greater thaa 
the particle, which is carried up. 
It may be now thought neceflary to fliew what 
becomes of our vapour and exhalation above ; or how 
they are to come down again. But I mufl: here beg 
your patience, yvhile I endeavour to (hew, that the 
afcent and defcent of vapour and exhalation, attended 
by this fire, is the principal caufe of all our winds. 
In doing of which, I hope to bring down the vapour 
and exhalations, and to explain the general phasno-* 
mena of the weather and barometer. 
It being admitted, that wind is only air put into 
motion, many have been the conjectures how that 
motion is caufed. Among which, the motion of 
the earth, and the air’s being rarefied by the fun, 
feem to ftand firfl:. The trade winds being moft 
regular, and occupying a confiderable part of the 
globe, it has been thought proper firfl: to account 
for them, from the afore-mentioned caufes. 
But I think, that thefe caufes by themfelves are 
not fufficient for the motion of thofe winds, and 
much lefs fo for the irregular motion of all the 
other v/inds. If the apparent motion of the air 
was occafioned by the diurnal revolution of the earth 
from weft to eaft (by the air’s being left behind), 
the motion muft be found more regular, and very ' 
different from what it is ; for in that cafe the greateft 
motion muft be at the equator, and from thence 
leflen by regular degrees to the poles % and muft be 
continued always equally one way, both day and; 
night, and at all feafons. But we find quite the 
contrary j the moft gentle gales blowing at the equar- 
