254 Prof. Oliver Lodge on the Seat of the 
ceases again, in the absence of coercitive force, as soon as the 
magnetizing force ceases to act. Such a condition of equili- 
brium cannot be imagined as produced otherwise than by the 
simultaneous action of attractive and repulsive forces. There 
must then be produced a nearly, but not quite, unstable equi- 
librium of the elementary magnets by the mutual action of all 
the neighbouring attractive and repulsive molecular forces, if 
the assumptions of Ampére’s theory are to correspond to facts. 
That a combination of molecular forces fulfilling this necessary 
requirement can be shown to be possible I do not venture to 
assert. 
XXX. On the Seat of the Electromotive Forces in the Voltaic 
Cell. By Professor Ouiver J. Lopex, D.Sc. 
[Continued from p. 190.*] 
TABLE OF CONTENTS. 
Chapter Il. Argumentative. Page 
7. Summary of the theoretical views which can be agreed to, and of 
the remaining points mm dispute!) 3. e522). 1. 2 eles eee 254 
8. Viewsof Clerk, Maxwell :ic:.aciesiaue os bores a ee 256 
9. Views of Bellats 0c. Oe oe ed eri oa are esa ee 257 
10. Argument that the Peltier effect does not necessarily measure 
Electromotive Force at junctions ........0010..s0eeeneee 259 
11. Hydraulic illustrations of the difference between Peltier and 
Volta forces, according to the views of the writer .......... 260 
12. Summary of condensed statements embodying orthodox views.. 263 
7. 
f ae result of the survey in regard to our special sub- 
ject of discussion may be summed up thus:—(1) that 
there is certainly an H.M.F. at the junction of two different 
substances, or even of the same substance in two different 
states ; and (2) that the total H.M.I’. of a circuit is the alge- 
braic sum of all such contact-forces at every junction in the 
circuit. Ido not know that these two propositions could be 
passed nem. con., but I believe that, provided they are properly 
understood, the dissenting minority would be a very small 
one. Itis probable that Professor Hxner would be in the 
minority, but I am unable to be sure of any one else. 
We can also make a negative proposition which will com- 
mand almost universal assent—viz. that if in the above second 
proposition, instead of the sum of the contact-forces at every 
junction, we attend only to the contact-forces at the metallic 
junctions, the proposition will no longer be true. This fact, 
that the metallic junctions are insufficient to account for all 
the E.M.F., was established by Becquerel, De la Rive, and 
* Scarcely any of this portion was read at Montreal, but it was given 
in substance to the Society of Telegraph Kngineers on March 26th. 
