1839.] Memorandum of Experiments, §c. 855 



nura wire already described, using the three-strand conductors led 

 through water in the tank of the Medical College. 



The result was, that the conductors being three inches apart from each 

 other, and prevented from mutual contact by pieces of wood, as shewn 

 in fig. 5, the platinum wire ignited gunpowder in a bottle under 

 water, to a distance one-third the length of that at which explosion 

 would occur were the conductors dry. 



This fact enabled me in the explosion of the barque "Equitable," here- 

 inafter described, to dispense with the insulation of the conductors al- 

 together, and to use naked three-strand wires, in the ladder-form, as 

 represented in the plate. 



It was manifest however that the water did interfere so much as to 

 cut off two-thirds of the electricity in circulation from the stand- 

 ard battery employed. It was also found that approximating the 

 wires towards each other to the distance of one and a half inch, pro- 

 duced a nearly proportionate diminution of the igniting distance. But 

 separating the wires to the distance of three feet did not, on the 

 other hand, materially lengthen the igniting distance. I did not 

 attempt to trace the law by which this effect is regulated — neither 

 time nor means were at my command to do so. But from one and a half 

 inch to three feet constituted the limits within which, in a practical 

 point of view, it was of the least interest to study the phenomenon. 



Floating conductors, construction of. 



The preceding experiments made it manifest that to effect subaque- 

 ous explosions in fresh water with perfect certainty, naked wires, three 

 inches apart, might be used to the distance or depth of 130 feet. It next 

 became a point of interest to learn how far the distance might be ex- 

 tended by floating or insulating the portion of wires not necessarily 

 immersed in water. 



Several plans for floating the wires were tried ; for example, earthen 

 pots kept at a distance by slips of bamboo were used, but found 

 very unmanageable, the breakage of one pot frequently throwing the 

 whole line into confusion, and sinking so many of these frail vessels 

 as to prevent any certain results being obtained. 



I then tried corks, and with complete success. One of the conduc- 



