328 Facts in Reference to the Spark, &c. 
accompanying is important, that the prior claims of our fellow coun- 
tryman may not be overlooked. 
Very respectfully yours, 
A. D. Bacue. 
One of the Secretaries Am. Philos. Soc. 
Philadelphia, Feb. 7th, 1835. 
Extract from the proceedings of the stated meeting of the Ameri- 
can Philosophical Society, January 16, 1835. 
The following facts in reference to the spark, shock, &c., from a 
galvanic battery, of a single pair when the poles are united by a 
long conductor, communicated by Professor Joseph Henry, and 
those relating to the spark were illustrated experimentally. 
1. A long wire gives a more intense spark than a short one. 
There is, however, with a given surface of zinc a length beyond 
which the effect is not increased; a wire of one hundred and twen- 
ty feet gave about the same intensity of spark as one of two hundred 
and forty feet. 
2. A thick wire gives a larger spark than a smaller one of the 
same leneth. 
3. A wire coiled into a helix, gives a more vivid spark than the 
same wire when uncoiled. 
4. A ribbon of copper, coiled into a flat spiral, gives a more in- 
tense spark than any other arrangement yet tried. 
5. ‘The effect is increased, by using a longer and wider ribbon, to 
an extent not yet determined. ‘The greatest effect has been produ- 
ced by a coil ninety six feet long, and weighing 15 lbs.; a larger 
conductor has not been received. 
6. A ribbon of copper, first doubled into two strands, and then 
coiled into a flat spiral, gives no spark, ora very feeble one. 
7. Large copper handles, soldered to the ends of the coil of nine- 
ty six feet, and these grasped by both, one by each hand, a shock is 
felt at the elbows, when the contact is broken in a battery of a sin- 
gle pair with one and a half feet of zinc surface. 
8. A shock is also felt when the copper of the battery is grasped 
with one hand, and one of the handles with the other; the intensity, 
however, is not as great as in the last case. This method of receiv- 
ing the shock may be called the direct method, the other the lateral 
one. 
