relating to Atmospherical Electricity. 255 
diminish the apparent disproportion. And as for the remain- 
ing difference, I also attribute a good deal of it to the accuracy 
of my present mode of obtaining atmospherical electricity, 
with a more complete apparatus ; by which I have been able 
to collect the electric fluid, in sufficient quantity to ascertain 
the kind which predominates in the atmosphere, even in its 
weakest state. I have, therefore, found it an easy matter to fix 
the kind of electricity that the aqueous vapours in the air were 
charged with in each day throughout the year. 
From repeated observations, and long experience, I am per- 
fectly satisfied that the aqueous vapours, suspended in the air, 
are constantly electrified ; requiring only the aid of a proper 
collector, to render the effects of their electricity at all times 
sensible. And for this reason, there may be justly said to be, 
an electrical atmosphere within our aerial atmosphere. 
During a course of moderate weather, the electricity of the 
atmosphere is invariably positive ; and exhibits a flux and 
reflux, which generally causes it to increase and decrease twice 
in every twenty-four hours. The moments of its greatest force 
are about two or three hours after the rising, and some time 
before and after the setting, of the sun ; those when it is 
weakest, are from mid-day to about four o’clock. The pe- 
riodical electricity of the atmosphere seems to be manifestly 
influenced by heat and cold. Hence it plainly appears, why 
we always find warm small rain to be but weakly electrified ; 
when cold rain, which falls in large drops, is the most intensely 
•electrified of any. 
The abovementioned eighth day of May, completes my se- 
cond year’s journal ; which, agreeable to my promise, I have 
now the honour of presenting to the Royal Society, with a 
LI 2 
