272 Mr. Read's Experiments and Observations 
must have been wholly deprived of every particle of its former 
charge. 
The day after this, the heap of leaves was laid open, and 
every twig and leaf exhibited a covering of white mould ; but 
after this, the doubler always gave the same kind of electricity 
when worked on the leaves, as in any other part of the open 
air, namely, positive. In order to be fully satisfied in this 
matter I determined to try it on a large dunghill, whence a 
greater quantity of putrid effluvium must ascend. I also re- 
solved to make the experiment when the air was sharp and 
frosty, because then the atmospheric electricity is not only of 
the positive kind, but uniformly the same in all places, from 
the surface of uncontaminated earth to any height we can go. 
The weather on the first day of January, 1794, was quite such 
as I desired for this business, that is, it was frosty, and accom- 
panied with a very slight dry fog, therm. 31 0 . 
I conjectured that Mr. Tattersall (a dealer in horses in 
my neighbourhood) might be possessed of a large dunghill ; I 
therefore went to his house, and was taken into his garden, 
where there was a great quantity of it. I first went upon the 
highest part of the dunghill, and held the doubler in one hand 
a little above the dung, yet within the reach of the ascending 
pale coloured vapour, and with the other I turned the revolv- 
ing plate five or six times, by which means the doubler became 
electrified positively; which was known to be at that time the 
general electrical state of the atmosphere. The doubler was 
now lowered, and placed upon the dung; and here also it be- 
came charged by a few turns of the revolving plate, which 
made me suspect that I had not completely cleared the doubler 
