On the Action of a Spiral Conductor, &c. 329 
9. The decomposition of a liquid is effected by the use of the coil 
with a battery of a single pair, by interrupting the current, and intro- 
ducing a pair of decomposing wires. 
10. A mixture of oxygen and hydrogen is also exploded by means 
of the coil, and breaking the contact, in a bladder containing the mix- 
ture. 
11. The property of producing an intense spark is induced, on a 
short wire, by introducing, at any point of a compound galvanic cur- 
rent, a large flat spiral, and joining the poles by the short wire. 
12. A spark is produced when the plates of a single battery are 
separated by a foot or more of diluted acid. 
13. Little or no increase in the effect is produced by inserting a 
piece of soft iron into the centre of a flat spiral. 
14. The effect produced by an electro-magnetic magnet, in giving 
the shock, is due principally to the coiling of the long wire which 
surrounds the soft iron. 
Appendix to the above—on the Action of a Spiral Conductor, &c. ; 
by Prof. Joseru Henry, Princeton College. 
TO PROF. SILLIMAN. 
Wiru this I send you a copy of a paper communicated by me to 
the American Philosophical Society, on the influence of a spiral 
conductor in increasing the intensity of Electricity from a galvanic 
arrangement of a single pair. As the part of the transactions which 
contains the paper has not yet been distributed, I regret that I am 
not at liberty to request you to insert the article for more general 
diffusion in your valuable Journal. An abstract however of the 
principal facts was ordered to be published, and appeared in the 
March number of the Franklin Journal. A copy was also sent by 
Prof. Bache for insertion in the American Journal ; but as it did not 
appear in the Jast number, you will confer a favor by inserting it in 
the next.* 
Should you wish to repeat the experiments, you will find them 
most interestingly exhibited with one of Dr. Hare’s Calorimotors. 
Ifa galvanic current of very low intensity, from this instrument, be 
transmitted through a spiral conductor formed of copper ribbon about 
one inch wide, from sixty to one hundred feet long, well covered 
* Then mislaid, but now inserted, see above. 
42 
Vou. XXVIII.—No. 2 
