on the Wires of the Electric Telegraph. 187 



investigations in dynamic electricity, accounts of which are to 

 be found in the Proceedings and Transactions of this Institu- 

 tion. 



From all the information on the subject of the action of the 

 electricity of the atmosphere <m the wires of the telegraph, it 

 is evident that effects are produced in several different ways. 



1. The wires of the telegraph are liable to be struck by a 

 direct discharge of lightning from the clouds, and several cases 

 of this kind have been noticed during the present season. 

 About the 20th of May the lightning struck the elevated part 

 of the wire, which is supported on a high mast at the place 

 where the telegraph crosses the Hackensack river. The fluid 

 passed along the wire each way, from the point which received 

 the discharge, for several miles, striking off at irregular inter- 

 vals down the supporting poles. At each place where the dis- 

 charge to a pole took place, a number of sharp explosions 

 were heard in succession, resembling the rapid reports of 

 several rifles. During another storm, the wire was struck in 

 two places in Pennsylvania, on the route between Philadelphia 

 and New York ; at one of these places twelve poles were 

 struck, and at the other eight. In the latter case the remark- 

 able fact was observed, that every other pole escaped the dis- 

 charge ; and the same phaenomenon was observed, though in 

 a less marked degree, near the Hackensack river. In some 

 instances the lightning has been seen coursing along the wire 

 in a stream of light ; and in another case it is described as 

 exploding from the wire at certain points, though there were 

 no bodies in the vicinity to attract it from the conductor. 



In discussing these and other facts to be mentioned here- 

 after, we shall, for convenience, adopt the principles and lan- 

 guage of the theoi-y which refers the phasnomena of electricity 

 to the action of a fluid, of which the particles repel each other, 

 and are attracted by the particles of other matter. Although 

 it cannot be affirmed that this theory is an actual representa- 

 tion of the cause of the phsenomena as they are produced in 

 nature, yet it may be asserted that it is, in the present state of 

 science, an accurate mode of expressing the laws of electrical 

 action, so far as tliey have been made out ; and that though 

 there are a number nfpha^nomena which have not as yet been 

 referred to tliis theory, there are none which are proved to 

 be directly at variance with it. 



That the wires of the telegraph should be frequently struck 

 by a direct discharge of lightning, is not surprising, when we 

 consider the great length of the conductor, and consequently 

 tlie many points along the surface of tiie earth through which 

 it must pass peculiarly liable to receive the discharge from 



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