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“ I found from 13|^® to 14° of torsion required to bring the 
index to zero when urged aside by the electromotive force of 
ten zinc-copper water cells. The Leyden phial held so well, 
that the sensibility of the electrometer measured in that way 
did not fall more than from 13^° to 13^° in three days. 
“ The atmospheric effect ranged from 30° to above 420° 
during the four days which I had to test it — that is to say, 
the electromotive force per foot of air measured horizontally 
from the side of the house was from nine to one hundred and 
twenty-six zinc-copper water cells. The weather was almost 
perfectly settled, either calm, or with slight east wind, and in 
general an easterly haze in the air. The electrometer twice 
within half an hour went above 420°, there being at the 
time a fresh temporary breeze from the east. What I had 
previously observed regarding the effect of east wind was 
amply confirmed. Invariably the electrometer showed very 
high positive in fine weather, before and during east wind. 
It generally rose very much, shortly before a slight puff of 
wind from that quarter, and continued high till the breeze 
would begin to abate. I never once observed the electro- 
meter going up unusually high during fair weather w’ithout 
east wind following immediately. One evening in August I 
did not perceive the east wind at all, when warned by the 
electrometer to expect it ; but I took the precaution of bring- 
ing my boat up to a safe part of the beach, and immediately 
found by waves coming in that the east wind must be blow- 
ing a short distance out at sea, although it did not get so far 
as the shore. 
“ I made a slight commencement of the electro-geodesy 
which I pointed out as desirable at the British Association, 
and in the course of two days, namely, October 3rd and 4tb, 
got some very decided results. Macfarlane, and one of my 
former laboratory and Agamemnon assistants, Russel, came 
down to Arran for the purpose. Mr. Russel and I went up 
Goatfell on the 3rd inst. with the portable electrometer and 
