Influence of Magnetic Force on the Electric Discharge. 241 
battery was first shown by an ordinary gold-leaf electroscope; one 
end of the battery being insulated, a wire from the other end was 
connected with the electroscope; the leaves diverged; on now con- 
necting the other end of the battery with the earth, the tension of 
the end connected with the electrometer rose, according to a well- 
known law, and the divergence was greatly augmented. 
9. A large receiver (selected from Mr. Gassiot’s fine collection), 
in which a vacuum had been obtained by filling it with carbonic acid 
gas, exhausting it, and permitting the residue to be absorbed by 
caustic potash, was placed equatorially between the poles of the 
large electro-magnet. The jar was about six inches wide, and the 
distance between its electrodes was ten inches. The negative elec- 
trode consisted of a copper dish, four inches in diameter ; the positive 
one was a brass wire. 
On the 16th of this month an accident occurred to this jar. Mr. 
Faraday, Mr. Gassiot, and the speaker had been observing the dis- 
charge of the nitric acid battery through it. Stratified discharges 
passed when the ends of the battery were connected with the elec- 
trodes of the receiver; and on one occasion the discharge exhibited 
an extraordinary effulgence ; the positive wire emitted light of daz- 
zling brightness, and finally gave evidence of fusion. On inter- 
rupting the circuit, the positive wire was found to be shortened about 
half an inch, its metal having been scattered by the discharge over 
the interior surface of the tube. 
10. The receiver in this condition was placed before the audience 
in the position mentioned above. When the ends of the 400-cell 
battery were connected with the wires of the receiver, no discharge 
passed; but on touching momentarily with the finger any portion of 
the wire between the positive electrode of the receiver and the po- 
sitive pole of the battery, a brilliant discharge instantly passed, and 
continued as long as the connexion with the battery was maintained. 
This experiment was several times repeated: the connexion with 
the ends of the battery was not sufficient to produce the discharge ; 
but in all cases the touching of the positive wire caused the discharge 
to flash through the receiver. 
Previous to the fusion of the wire above referred to, this discharge 
usually exhibited fine stratification: its general character now was 
that of a steady glow, through which, however, intermittent lu- 
minous gushes took place, each of which presented the stratified 
appearance. 
11. Onexciting the magnet between whose poles the receiver was 
placed, the steady glow curved up or down according to the polarity 
of the magnet, and resolved itself into a series of effulgent transverse 
bars of light. These appeared to travel from the positive wire along 
the surface of the jar. The deflected luminous current was finally 
extinguished by the action of the magnet. 
12. When the circuit of the magnet was made and immediately 
interrupted, the appearance of the discharge was extremely singular. 
At first the strata rushed from the positive electrode along the upper 
