[ 45 ° ] 
no mention of what the ftand or ballance is made ; 
though a difference in the materials will, I apprehend, 
make fome difference in the experiment. And if 
the cork is, as you fay, theflze of a pea , it will be a 
confiderable objection with me : and the more fo, if it is 
to be moiftened with water. For the force employed 
to move it, in fome of my experiments, is too incon- 
fiderable. And I fhould imagine the ballance itfelf 
could not be very nicely adjufled ; becaufe fuch an in- 
creafe in the weight of the cork, by moiftening it (as 
you fay) from time to time, ought to make it not 
only preponderate, but unfteady ; as an evaporation 
of the moifture is conftantly making fome alteration 
in the weight. My apparatus contrived for the fame 
purpofes, hath already been defcribed, except that 
part of it which refpeds the lize. of the pith balls, 
and each of thefeare about the thirtieth part of a pea . 
This fmallnefs, neverthelefs, does not require any moif- 
ture to retain the eledric fluid, as the balls communicate 
with the fineft flaxen threads, and the threads with a 
flender piece of wood, about one inch long, and the 
greater part one tenth of an inch thick; with the angles 
rounded off, and polifhed. This is fixed upon the end 
of a cylinder of amber, properly fupported. But that 
there may be no miftake in the conftrudion thereof, 
I have given a drawing and defcription of the one 
I ufe at prefent, fee fig. 2. When I at any time want 
to examine the ftate of the Tourmalin , it is brought 
flowly towards the eledrified balls in an horizontal 
diredion. 
Your glafs ftand feems liable to an objedion, unlefs 
the air be extreamly dry : becaufe the mere breath- 
ing, if not properly guarded againft, in very delicate 
experi- 
