DISCOURSE OF W. B. TAYLOR: NOTES. 395 



" Extract from the proceedings of the stated meeting of the American 

 Philosophical Society, January 16 , 1835. 



"The following facts in reference to the spark, shock, &c. from 

 a galvanic battery, when the poles are united by a long conductor, 

 were 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, a length beyond which the effect is not increased ; 

 a wire of 120 feet gave about the same intensity of spark as one of 

 240 feet. 



" 2. A thick wire gives a larger spark than a smaller one of the 

 same length. 



" 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 

 intense 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 pro- 

 duced by a coil 96 feet long, and weighing 15 pounds; 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, or a very feeble one. 



" 7. Large copper handles, soldered to the ends of the coil of 96 

 feet, and these both grasped, one by each hand, a shock is felt at 

 the elbows, when the contact is broken in a battery 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 inten- 

 sity however is not as great as in the last case. This method of 

 receiving the shock may be called the direct method, the other the 

 lateral one. 



" 9. The decomposition of a liquid is effected by the use of the 

 coil from a single pair, by intermitting the current, and introducing 

 a pair of decomposing wires. 



"10. A mixture of oxygen and hydrogen is also exploded by 

 using the coil, and breaking the contact, in a bladder containing the 

 mixture. 



"11. The property of producing an intense spark is induced, on 

 a short wire, by introducing, at any point of a compound galvanic 

 current, a large flat spiral. 



"12. A spark is produced even when the plates of a single bat- 

 tery are separated by a foot or more of diluted acid. 



