14 Charles Grafton Page. 
tive and trip given by J. J. Ber are Esq., in the American 
Polytechnic J ournal, vol. iv, p 257. 
a) 
y made in a course of lectures 
ieee in New York city, some account was given in the 
Scientific American, and they need only be-mentioned here, as 
they were chiefly a repetition of such as we have already de- 
scribe 
The grand scale on which these experiments were conducted ' 
afforded a rare opportunity for observing some very interesting 
and instructive incidental phenomena, which were publishe 
by Prof. Page partly in this. Journal at the time, aa: partly in 
the American Polytechnic Journal, and are worthy to be re- 
called here. When the battery circuit through the great coil 
around the great electro-magnet was broken, the prolongation 
of the falling current by the induction upon ‘it of itself and of 
the fa magnetism, became so extraordinary as to be dis- 
ae cognizable to the senses, and when the battery was cut 
+ by making metallic contact of the extremities of the coil, 
6 a renewed break in the metallic circuit showed a spark at 
any time within half a second. With the coil alone he esti- 
mated the time of the rise and fall of the current, by aid 
of a metronome, at jth or 3th of a second, and with the soft 
iron bar included at from 4 ‘to $ths of a second. He concluded 
that the time of fall of the current on breaking the batte 
circuit was about the same as the time of rise of the current. 
But the time of rise, with abundant battery surface, is prob- 
ably about the same as the time of fall in the closed metallic 
circuit, and hence it seems probable the result mentioned was 
incidental to the intensity of the particular battery used, which 
may have been somewhat equal to the resistance of the “are 
of flame.” In the case of the “(fall ime 104 of 532 Pane 
the lect eee the induction spark, though ay from 
quantity and unusually long continuance of the current, ° 
was quiet ; but when the break was made near the pole of the 
electro- et, the connecting wires being drawn somewhat 
quickly an widely asunder, the conflict of the current in the 
opening with the powerful deflecting force of the electro-mag- 
net was very remarkable, and produced a loud report, and vivid 
flash of i Prof. , Page varied and studied the conditions 
of this interesting phenomenon with considerable care, an 
described i them f in this Journal for March, 1851. 
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