Associated cases of Current and Static Effects. 199 



floor of a dry warehouse and connected in one series, for com- 

 parison with that under water. 



Consider now an insulated battery of 360 pairs of plates 

 (4x3 inches) having one extremity to the earth ; the water wire 

 with both its insulated ends in the room, and a good earth dis- 

 charge wire ready for the requisite communication : when the 

 fi'ee battery end was placed in contact with the water wire and 

 then removed, and afterwards a person touching tlic earth dis- 

 charge touched also the wire, he received a powerful shock. The 

 shock was rather that of a voltaic than of a Leyden battery ; it 

 occupied time, and by quick tapping touches could be divided 

 into numerous small shocks ; I obtained as many as forty sen- 

 sible shocks from one charge of the wire. If time were allowed 

 to intervene between the charge and discharge of the wire, the 

 shock was less ; but it was sensible after two, three, or four 

 minutes, or even a longer period. 



When, after the wire had been in contact with the battery, it 

 was placed in contact with a Statham's fuse, it ignited the fuse 

 (or even six fuses in succession) vividly ; it could unite the fuse 

 three or four seconds after separation from the battery. When, 

 having been in contact with the battery, it was separated and 

 placed in contact with a galvanometer, it affected the instrument 

 very powerfully ; it acted on it, though less powerfully, after the 

 lapse of four or five minutes, and even affected it sensibly twenty 

 or thirty minutes after it had been separated from the battery. 

 When the insulated galvanometer was permanently attached to 

 the end of the water wire, and the battery pole was brought in 

 contact with the free end of the instrument, it was most instruct- 

 ive to see the great rush of electricity into the wire ; yet after 

 that was over, though the contact was continued, the deflection 

 was not more than 5°, so high was the insulation. Then sepa- 

 rating the battery from the galvanometer, and touching the latter 

 with the earth wire, it was just as striking to see the electricity 

 rush out of the wire, holding for a time the magnet of the instru- 

 ment in the reverse direction to that due to the ingress or charge. 



These effects were produced equally well with either pole of 

 the battery or with either end of the wire ; and whether the 

 electric condition was conferred and withdrawn at the same end, 

 or at the opposite ends of the 100 miles, made no difference in 

 the results. An intensity battery was required, for reasons which 

 will be very evident in the sequel. That employed was able to 

 decompose only a very small quantity of water in a given time. 

 A Grove's battery of eight or ten pair of plates, which would 

 have far sui^jassed it in this respect, would have had scarcely a 

 sensibh; power in affecting the wire. 



When the 100 miles of wire in the air were experimented 



