134 Mr. henly’s Experiments and 
It is a queftion by no means decided, how the clouds be- 
come eledtrified ? But if we fuppofe the electric matter to 
be a pure, ethereal, elementary fire, refident in all bo- 
dies; that the great procefs of vegetation is carried on 
by means of this fubtile, adtive, volatile, and pervading 
element ; that it is continually exhaling from all the ve- 
getable tribe ; that as evaporation is a remarkable agent 
in the cooling of heated fubftances, that is, a good con- 
dudtor of their fire, as I am well allured it is of elcdtri- 
city ; may we not conclude, that this is one great caufe 
of the clouds becoming at times furcharged with this 
fluid? The great effedt of eledlricity in promoting ve- 
getation, hath been fully proved by Dr. de maimbray, 
the abbe nollet, Mr. jallabert, and other gentle- 
men, and was very remarkable in that year when the 
fatal earthquake happened at Lifbon. Dr. stukeley’s 
obfervations on the frequent appearances of fire-balls, 
corufcations, and aurorce boreales , at this time (which I 
well remember) deferve to be particularly noticed; and 
it is generally remarked, that thunder-ftorms are pre- 
ceded by a continuance of hot weather, and that a moderate 
temperature immediately fucceeds the ftorm. The re- 
marks and obfervations of the worthy Dr. hales on this 
fubjedt feern alfo to merit peculiar attention. Further, 
as the rays of the fun, concentrated by a powerful burn- 
