204 Conduction of Galvanic Electricity through Moist Air. 
The inductive action of a helix upon inclosed bars of soft iron 
of uniform lengths and transverse diameters, is directly in pro- 
_ portion to the weight of those bars. 
~The bar No. 3 was then inserted, and it was drawn down by a 
force of five pounds and one ounce; but here the result became — 
complicated, and will require further trials with many variations of 
length and also diameter of the soft iron bars. «It probably woud 
not follow that the indefinite increase of weight by increase of: 
length would give a proportionate increase of inductive action, for 
there must soon be a limit for every size of bar, and this limit will 
— with the different sizes. The experiments as tried, however, 
are in favor of the conclusion that the action is as the ities 
not the surface. One experiment remains yet to be tried in this 
connexion, for which [ have not yet had opportunity, viz. to 
make the masses the same, and vary the diameters. 'The resul 
here also would be complicated by the element of the distance. 
- The second investigation was directed to the law of Ampére, 
viz. that the action of helices upon a magnetic bar, is inversely 
as the distance. 'The same law of course applies to soft iron as 
to permarient magnets. The law was fully confirmed. Great 
care was taken in the preparation for these experiments. The 
helices before mentioned were all wound upon steel mandrels, 
_ carefully turned and polished, and all of the same length of wire. 
The bores of three helices regularly increased in diameter ;'; of 
an inch. When these helices were placed in succession upon a | 
bar of soft iron, they gave by the balance, f rsely pro- 
ee to the distance. é opti he < sitlh 
hee 
"city through Moist Air ; by Cuas. G. Pace, M. D., Prof. Chem. 
and Pharm., Columbian College, Washington, D. C. 
‘Pavan or eight years since, I observed a curious fact, which 
Jed me to the conclusion that many substances considered as per- 
fect insulators, or rather non-conductors of galvanic electricity, 
might under certain circumstances prove conductors. I took two 
3 oe, of zinc and coiled them together, the two sheets be- 
5 a ribs India rubber cloth. The sheets of 
Arr. XVIII.—On the perigee Conduction of Galvanic Electri- 
with: the- poles of a battery, = 
ica — ie 
