made with the Doubler of Electricity. 2 Cg 
feet and six inches out of the garret. Had the direction of the 
wind been north or south, it would have passed through the 
garret with force, and would, no doubt, have changed by re- 
gular gradation its electricity to positive; a fact that I have 
often observed to succeed very quickly. 
I like wise observed, that when the excessive heat of the sun 
was full upon any other room in my house, it was capable of 
effecting a change in their electrical state, excepting in those 
which were under ground ; for in the two kitchens, open area, 
and coal-vault, the doubler became electrified positively ; in 
the two former rooms speedily, but in the two latter, that lay 
more to the sun, slowly. I have observed before, that the air 
in the garret was infected with a noxious exhalation, which I 
now judge came from the wearing apparel laid up in it : 
whereas the air in the kitchens was not only much cooler, but 
perfectly clear of all offensive exhalations. However, on the 
1.7th of July, the two kitchens were white-washed and paint- 
ed, and of course were filled with a noxious effluvium. The 
day after, I worked the doubler in the kitchens, and by a very 
few turns of the revolving plate it gave negative electricity. 
Knightsbridge charity-school fills up a piece of ground be- 
tween the north end of the chapel and Hyde- Park wall ; and 
the main sewer of that neighbourhood runs at no great depth 
under it; the number of children educated in this school is 
thought by some to be too great for the size of the school ; on 
these accounts it becomes infected with a very disagreeable 
stench, especially when the door and windows are shut up ; l 
have sometimes found the noxious effluvium so very strong in 
this school, that I have hastened out to breathe a purer air. I 
have often examined the electrical state of the air in this 
