Observations on some Experiments in Electricity. 63 
Hence it appears that the spring months are most favorable to elec- 
trical operations conducted ’in an atmosphere not artificially heated ; 
but that the winter season offers greater facilities than any other for 
gaining a temporary advantage by elevating the temperature of a 
close and dry apartment. Professor Hare’s prannaied in the last No. 
of this Journal; on the facility of charging batteries in oo an apart- 
ment, without a connexion with the ‘* common reservoir,” is entirely 
in accordance with my own observations and practice in that particu- 
lar, nor is it of the least importance whether the battery be insulated 
or not, or whether its interior surface be charged from the rubber 
or from the collector, provided the source of the interior charge, be 
insulated, when the outside of the battery is not. Nor need we be 
under any apprehension that the more exposed situation of the posi- 
tive charge, when outside, and its greater facility of passing through 
the air, will diminish the durability of the charge ; for if the positive 
charge, when on the inside has.a narrow passage by which to get out, 
so has it when on the outside, a narrow entrance by which to get 
in; and the latter course it must take, before the discharge can be 
effected ,—as all will agree, whether they adopt the theory of one fluid 
or of two. 
In accordance with the foregoing remarks, I have, danas: the pre- 
sent month, (July, 1833,) compared the action of a machine, when 
the dew-point and temperature were 30° apart, with its performance 
when they were but 5° from each other.’ In the former case the 
sparks were nine inches, and in the latter, scarcely one inch. ‘The 
first experiment was performed on the 19th, when the horizon 
was partly overcast, (temperature 81°—dew-point 51°,) and the last 
on the 24th, when the sky was perfectly cloudless ;—temperature 80°, 
and dew-point 75°. ‘The moisture in a cubic inch of air on the 19th 
was .00254757 gr., and on the 24th it was .00537226 gr. 
The following experiments illustrate several of the preceding ob- 
servations. 
1. July’ 25th, the temperature in the open air was 79°, and the 
dew-point 683°. An apartment which had been closed for two or 
three days, was found at the temperature of 82°, and with a dew- 
point at 76°. The machine,-(a four feet plate,) was set in motion, 
having a single pair of rubbers, and collectors on the opposite end 
of the diameter. The sparks were now one inch and two-tenths 
long. The quantity of moisture in a cubic inch of this air was 
00553634 grains. 
