154 Proceedings of Royal Society of Edinburgh. . [sess. 
the total transverse effect at a given temperature as made up — 
except at the neutral temperature t= — ^ — of two parts : (1) The 
transverse Peltier effect proportional to the transverse power multi- 
plied by the absolute temperature, and (2) the transverse Thomson 
effect proportional to the absolute temperature. 
Leduc has also expressed the electromotive force of the trans- 
verse effect as a parabolic function of the temperature. He 
obtained the maximum value at 48 - 7° C. 
Hall has examined the variation of transverse effect with tem- 
perature by constant external field in several substances, chiefly, 
however, in the magnetic metals. 
In them, as before stated, the effect must necessarily be a very 
complex affair ; with nickel Hall has found that the curve repre- 
senting the transverse effect at various temperatures bears a great 
resemblance to the corresponding magnetisation temperature curve. 
The effect of thermo-electricity, if it exists in this metal, is com- 
pletely masked at the temperatures Hall has experimented at; 
what results would be given at lower temperatures, such as those 
used by Dewar and Fleming in their experiments on thermo- 
electricity, must be settled by new experiments. At any rate, it 
suggests a method for the consideration of the magnetic properties 
of the paramagnetic bodies at low temperatures. 
There are other substances which give better hopes of definite 
results than the paramagnetic metals. A glance at the curves 
published with Dewar and Fleming’s above-cited article will show 
what these are. Antimony, for instance, has a very characteristic 
curve ; the tangent to its thermo-electric force curve is twice 
parallel to the line of lead. 
Palladium and platinum have also very distinctly marked maxi- 
mum values. 
Evidently much more experimental data is necessary before we 
can say quite generally that the transverse effect is a function of the 
thermo-electric force ; when we have these we may, perhaps, profit- 
ably study the exact relation between the molecular motion of heat 
and that of magnetism. At present we are only justified in saying 
that in bismuth and in alloys there is a very close connection between 
the thermo-electric properties and the transverse effect. Probably 
