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L. Influence of atmospheric Moisture on an Electric Column 
composed of Discs of Zine and Silver. By’ Mr. Tuomas 
How py, of Hereford. 
. Hereford, March 24, 1814. 
SR Re in the spring of last year, I discovered that the 
regularity of the action of Mr. De Luc’s Electric Column was 
much affected by the varying state of moisture in the atmosphere ; 
and in consequence of this discovery, previous to the 19th of 
April, I had repeatedly exposed an instrument of the kind to the 
rays of the sun, as well as to the warmth of a fire, in order to 
dissipate from the surface of the glass tube the film of moisture 
which that substance when unvarnished jnvariably acquires from 
the air, except when the latter is in a very dry state. During 
the succeeding summer and autumn, as well as the present win= 
ter, | have often observed the alternate effects produced on the 
column by a moist atmosphere and a dry one. As the quantity 
of moisture in the ambient air increases, a greater deposition of 
it takes place on the surface of the glass tube; and in proportion 
as this effect is produced, the insulatiag faculty of the glass is 
impaired, and the electrical phenomena of the.column are di- 
minished in intensity; because the electric fluid, which would 
otherwise accumulate at the zinc end of the column, seizing on 
the moisture, and by its means traversing the exterior surface of 
the tube, restores, either partially or entirely, between the ex- 
tremities of the column, the equilibrium which its electremotive 
power has a tendency to destroy. But in proportion as the am- 
bient air grows drier, the film of moisture which had been de- 
posited on the surface of the glass tube is lessened; and conse~ 
quently its resistance to the passage of the fluid is increased : 
an accumulation of electric fluid proportioned to that increased 
resistance, therefore, takes place at the zinc extremity of the 
column 5 and consequently the intensity of its electrical phe- 
nomena hecomes augmented. 
Experiments evincing the Influence of atmospheric Moisture on 
the Action of an Electric Column consisting of one thousand 
Dises of Zine and Silver, of a Gonsiruction similar to those 
described in Volume xxxy. p. 64, of Nichoison’s Journal ; 
made the 6th February 1814, 
Series 1, The positive extremity of the column resting on 
the cap of an electrometer, the negative communicating with the 
round; the gold-leaves diverging about a quarter of an inch, 
The extremity of the glass tube at the negative end of the co- 
fumn was touched with a finger, and the leaves instantly closed. 
They opened again very slowly; and when they had attained their 
former divergence, the tube'was touched at”the positive end, and 
the leaves closed as before. After they had opened again to 
Vol.43, No. 192, April 1814. {) their 
