476 
PINE ON ELECTRO-VEGETATION. 
I have deduced the following particulars : — 
The electricity of the air, as distinguished 
from that of clouds and storms, was not the 
object of his researches, till it incidentally 
fell under his observation in the course of 
his experiments with the view to the latter 
object. But he soon discovered, contrary 
to his expectations, that a clear atmosphere 
was attended with a constant positive elec- 
tricity ; while a generally clouded atmo- 
sphere either afforded comparatively feeble 
indications, or, as the clouds gathered to 
blackness, usually gave signs of a strongly 
negative influence. His general inference, 
that “ the air appears to be electrified at 
all times, and that its electricity is con- 
stantly positive fi was the result of frequent 
experiments made in the course of two years, 
by means of a kite with a wire extended 
through its string, and by an insulated elec- 
trometer of pith balls, affixed to the end of 
a rod, projecting from the upper part of his 
house at Islington. Having, however, ob- 
served a passage in Sir H. Davy’s “ Ele- 
ments of Chemistry,” in which he speaks 
of ” clouds as being usually negative,” and 
inclines to the conclusion, that plants are 
acted upon by a positive electricity in regard 
to the atmosphere, I took the liberty of re- 
questing the opinion of my friend, Mr. 
Sturgeon, as the result of the numerous ex- 
periments which I knew he had made upon 
the electricity of the atmosphere, and was 
favoured with the following obliging and 
satisfactory reply: — 
“ In the first place, I perfectly agree with 
you as to the solution of the results of Sir 
Humphrey Davy’s experiments on corn ; 
for the positive pot of a voltaic battery 
would supply the animating electric fluid to 
the germinating seed in precisely the same 
manner that nature supplies it from the 
atmosphere to the ground. As he does not 
state from what ‘ experiments made on the 
atmosphere,’ he draws his conclusion that 
* clouds are usually negative,’ I am unable 
to form any opinion respecting them ; but 
I must beg permission to state, that such a 
conclusion is quite at variance with the re- 
sult of my experiments. It is true, I have 
obtained negative charges at the kite-string, 
but the instances are very few indeed. Those 
which did occur were only whilst heavy 
clouds passed over the kite ; the indications 
both before and after the clouds’ transit 
being invariably positive. And even in those 
temporary exhibitions of negative electricity 
I am very far from concluding that the 
clouds themselves were negatively electric. 
The indications were those of the kite, 
which was floating much lower than the 
clouds; and the air in the vicinity of the 
kite was consequently the only part of the 
atmosphere explored during each experi- 
ment ; which air probably became nega- 
tive, or deprived of most of its natural elec- 
trieity by the repulsive force of the accu- 
mulated electric matter in the positively 
charged clouds. This assertion can hardly 
be construed into ‘ begging the question” 
or ‘ straining a point,’ because such phe- 
nomena are easily produced by experiment, 
and must frequently occur in nature, 
“ The results which I have obtained from 
experiments made at nearly all the seasons 
of the year, and at all times of the day, and 
many at night, induce me to believe that 
the general electric state of the atmosphere 
with its contained clouds, vapours, &c., is 
with reference to the earth positive. All 
electrical phenomena are relative, and con- 
sequently all our calculations respecting 
them have no other object than the 
ever-varying degrees of those relations ; 
but the relations themselves appear to be 
constant and uniform. Therefore I con- 
clude generally, and my conclusions are from 
direct experiments, that the atmosphere 
taken as a whole is constantly in an electro- 
positive state, with reference to the earth, 
and that in the atmosphere itself, the upper 
regions are constantly electro -positive, with 
reference to all those situated nearer to the 
surface of the earth. 
In corroboration of Mr. Sturgeon’s 
statement, my friend, Mr. Weekes, informs 
me, that about twenty years since, though 
little more than a youth, and knowing but 
litttle of what had been done by philoso- 
phers, but being exceedingly attached to 
electrical experiments, he mounted a large 
pole on the top of a very high tree ; on the 
top of which was fixed a large, sharp iron 
rod (insulated), and from it a wire commu- 
nicated with a rather large but delicate elec- 
trometer, placed in an adjoining cow-shed. 
“ I have,” he observes, “ turned to my ma- 
nuscript notes of that period, and, with sin- 
gular pleasure, I find that upwards of 90 
observations made with this apparatus dur- 
ing seven months, from December to July, 
are in perfect accordance with the experi- 
ments of our friend, Mr. Sturgeon, as well 
as your own theory.” 
The facts, then, of the constant presence 
of electric fluid in the atmosphere, and of 
the superior conducting efficacy of the 
points and tubes of vegetables above that 
of pointed metallic rods, or any other sub- 
stances in nature, are, I trust, sufficiently 
established ; from whence the constant mu- 
tual action between them appears a neces- 
sary consequence. The tubes of plants are 
continually imbibing the fluid from the at- 
mosphere, which is as constantly replenish- 
ed from some other source. That that 
source is no other than the sun, appears 
