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with a flash in the heavens. Now we cannot suppose, for a moment, 

 that the wire was actually struck at the time each flash took place; 

 and indeed it was observed that the sparks were produced when the 

 cloud and flash were at the distance of several miles to the east of 

 the line of the wire. The inevitable conclusion is, that all the exhi- 

 bition of electrical phenomena witnessed during the afternoon, was 

 purely the effects of induction, or the mere disturbance of the natural 

 electricity of the wire at a distance, without any transfer of the fluid 

 from the cloud to the apparatus. 



The discharge between the two portions of the wire continued for 

 more than an hour, when the effect became so powerful, that the su- 

 perintendent, alarmed for the safety of the building, connected the 

 long wire with the city gas pipes, and thus transmitted the current 

 silently to the ground. I was surprised at the quantity and intensity 

 of the current; it is well known, that to affect a common galvano- 

 meter with ordinary electricity, requires the discharge of a large bat- 

 tery; but such was the quantity of the induced current exhibited on 

 this occasion, that the needle of an ordinary vertical galvanometer, 

 with a short wire, and apparently of little sensibility, was moved se- 

 veral degrees. 



The pungency of the spark was also, as might have been expected, 

 very great. When a small break was made in the circuit, and the 

 parts joined by the forefinger and thumb, the discharge transmitted 

 through the hand affected the whole arm up to the shoulder. I was 

 informed by the superintendent, that on another occasion a spark 

 passed over the surface of the spool of wire, surrounding the legs of 

 the horse-shoe magnet at I'ight angles to the spires; and such was its 

 intensity and quantity, that all the wires across v/hich it passed were 

 melted at points in the same straight line as if they had been cut in 

 two by a sharp knife. 



The effects of the powerful discharges from the clouds may be pre- 

 vented, in a great degree, by erecting at intervals along the line, and 

 aside of the supporting poles, a metallic wire, connected with the 

 earth at the lower end, and terminating above at the distance of 

 about half an inch from the wire of the telegraph. By this arrange- 

 ment the insulation of the conductor will not be interfered with, while 

 the greater portion of the charge will be drawn off. 1 think this pre- 

 caution of great importance at places where the line crosses a river, 

 and is supported on high poles. Also in the vicinity of the office of 



