MR. DANIELL ON VOLTAIC COMBINATIONS. 
153 
fig-. 3., and a secondary circuit be formed as before with the cell No. 1. by the wire 
abode, a portion of the main current flowing from the copper of No. 5. to the zinc 
of No. 1, instead of passing through the electrolyte from g to h, finds a passage 
through the wire abode to h, and consequently will appear to flow in an opposite 
direction to the primary current or from the zinc to the copper. The resistance of 
the circuits may be so adjusted that the current may sometimes take one course and 
sometimes the opposite, and produce those oscillations of the needle from E. to W. 
which have been just described. 
The breaking of the secondary circuit did not affect the galvanometer of the pri- 
mary current, but the breaking of the primary circuit always turned the secondary 
current into the normal direction, and increased the deviation of its needle ; it re- 
duced it, in fact, to the condition of the direct current from the single cell. 
It is however obvious that these diverted currents of the complete circuit would 
not of themselves be sufficient to account for the stoppage of the main battery current 
of which we are in search ; nor has it yet been shown how they were produced when 
the main circuit was broken, as represented at fig. 1. In search of the explanation of 
these phenomena I turned my attention to the influence of the metallic steam-vessel 
upon the voltaic arrangement. 
When the battery was connected in the usual way with a galvanometer, and the 
needle was deflected 80° E., if the zinc electrode were lifted and made to touch the 
tin case in any part, it would remain deflected in the same direction 30°. If, on the 
other hand, the main circuit were broken at the copper electrode, and it were brought 
into contact with the tin, the deflection would be to the same amount in the same 
direction. The difference of that connection is shown at fig. 4, where t z represents 
the zinc electrode in connection with the tin, and passing to the zinc cup of the gal- 
vanometer G and the copper electrode C C in its usual position. On the other hand, 
z' z 1 represents the zinc electrode in its usual communication with the galvanometer, 
and the copper electrode o' t' in connection with the tin. The most striking result of 
this experiment is, that notwithstanding the connection of the tin with the galvano- 
meter is reversed, the current is in the same direction; or that the current, which we 
must conceive to flow from the tin in one connection, must flow to the tin in the 
other. To simplify the conditions of the experiment, I repeated it with a single cell. 
At the atmospheric temperature of 52°, when the circuit was completed in the usual 
way through the galvanometer, the deflection was 57° E. ; but no deflection was ob- 
tained by making connection with the tin. When steam was admitted, the ordinary 
battery current increased to 65°, and then contact with the hot tin produced a deflec- 
tion of 20° E. by either electrode. 
Four cells were now placed in the steam case upon plates of glass, and the action 
of the battery with the usual connections being first tried at the temperature of 54°, 
was found as follows : 
Galvanometer alone 
Galvanometer with voltameter . . 
. 70° E. 
. 50° E. 
MDCCCXXXVII. 
X 
