442 PHILOSOPHICAL TRANSACTIONS [aNNO J 747-8. 



several times, both then and afterward, and the electrical commotion felt across 

 the river. The length of this circuit, through which the electricity was propa- 

 gated, was at least 800 yards, more than 400 yards of which was formed by the 

 stream of the river. 



The observers on the Westminster shore not feeling the electrical commotion 

 equally strong with those of Surry, was judged to proceed from other causes 

 besides that of distance. For it must be considered, that the conducting wire 

 was almost throughout its whole length laid on Portland stone standing in water. 

 This stone, being in a great degree non-electric, is of itself a conductor of elec- 

 tricity ; and this stone standing in water, no more of the electricity was trans- 

 mitted to the observers on the Westminster shore than that proportion, in which 

 iron is more non-electric, and consequently a better conductor of electricity than 

 stone. Whether the conducting wire on the bridge was broken or no, and, con- 

 sequently, whether the observers on the Westminster shore felt the electrical 

 commotion or no, not only the observers on tlie Surry shore, who with their 

 wire formed part of the line, felt the shock in their arms; but those persons who 

 only stood on the stone steps there, and touched the wire with their fingers, felt 

 the electrical commotion in the arm of that hand which touched the wire. 

 Hence, and from a person feeling the electrical commotion standing on the wet 

 stone steps of the Westminster shore, though not forming part of the line, but 

 only touching the wire with his fingers, it was concluded, that besides the large 

 circuit before spoken of, there were formed several other subordinate circuits 

 between the same steps of the Surry shore, and the bridge by means of the 

 water; by which that part of the electrical power, felt by the observers on the 

 Surry side of the river, and not by those on the Westminster side, was dis- 

 charged. 



Dr. Bevis having observed, and which was likewise tried here, that however 

 well an electrified phial was charged, its iron hook would not fire the vapours of 

 warm spirit of wine held in a spoon and applied to it, if the person who held 

 the phial, and he who held the spoon, did not take each other by the hand, or 

 have some other non-electrical communication between them ; it was therefore 

 thought proper to try the effects of electricity on some warm spirit of wine 

 through the large circuit beforementioned. Accordingly the observers being 

 placed as before, both on the Westminster and Surry shores, no other alteration 

 was made in the beforementioned apparatus, than that the wire which connected 

 the gun-barrel with the iron hook of the coated phial being laid aside, the coated 

 phial itself was charged at the gun-barrel, and then brought in the hands of an 

 observer near the warm spirits in the spoon, which was placed on the short iron 

 rod beforementioned, which was connected with the wire which went to the ob- 

 servers on the Surry shore. On presenting properly the iron hook of the charged 



