494 M. PoggendorfF on Galvanic Circuits composed of 
the signs of inequality express which of the two fluids {a and h, 
fig. page 489) developes the strongest electromotive force 
when a pair of plates of the metals stated at the head of the 
column are immersed in them. The expression s<^w^ for in- 
stance, in the space common to the columns zinc-silver^ and 
hydrochloric acid water, indicates that in contact with zinc and 
silver the water excites a greater electromotive force than the 
hydrochloric acid ; or, in other words, that the current has a 
direction as if the zinc plate in the water were positive to the 
zinc plate immersed in the acid, the word positive being taken 
in the sense previously mentioned. 
I might also have added to the direction of the current, or 
the direction of the magnetic deflections, their magnitudes, as I 
always noted them carefully. But I have omitted this^ on 
the one hand, because the intensity of the current is no mea- 
sure of the difference of the electromotive forces under con- 
sideration, and also because in the present case it is at the 
same time a very variable element. In general the intensity of 
the current in this kind of circuits is most powerful in the first 
moment, and then rapidly decreases ; the amount and velocity 
of the decrease vary however considerably. This causes among 
other things that in two cases the difference of the two first de- 
flections of the needle, to the right and to the left, may indeed 
be equal, but the magnitudes of the deflections differ consider- 
ably. In the one case these deflections amounted perhaps to 
10° and 8°, in the other to 30° and 28°. In general the inten- 
sity of the current only descends to zero, but at times it also 
increases towards the opposite side. Sometimes this reversion 
of the current takes place so rapidly, that, for example, the 
first deflection of the needle, perhaps of 50° to the right, is im- 
mediately succeeded by one on the left of ?0°. Now and then 
the intensity of the current is but feeble in the first moment, 
increases then for a time, and then gradually sinks to zero. 
Such variations render a numerical comparison of the intensity 
of the current in the different cases quite impossible, especially 
as in general, on the repetition of one and the same experiment, 
highly different values are obtained for the magnitudes of the 
deflections. I have therefore merely stated in general, in the 
notes to the Table, when the current was especially strong or 
feeble : when reversions of the current result, they are for the 
most part already indicated in the Table by the signs of in- 
equality placed beneath one another. 
