1895 - 96 .] Dr Beattie on Thermo-electricity in Bismuth. 147 
Metal. 
R. 
Gold, 
— 
0 00071 
Silver, 
— 
0-00083 
Zinc, 
. + 
0-00041 
Cadmium, . 
. + 
0-00055 
Iron, 
. + 
0-0113 
Antimony, 
• + 
0-192 
Tellurium, 
. 4- 
532-000 
The two irregularities, so far as direction is concerned, are cobalt 
and lead. 
In considering the magnitude of the Hall effect, we must 
remember that different specimens have been used for thermo- 
electric and for transverse effect purposes ; that slight changes in 
structure and in composition have a great influence on the thermo- 
electric position of a metal ; and that probably the quantitative 
differences in the transverse effect in different specimens of the 
same metal are largely due to difference of structure and to the 
presence of foreign matter. Thus the irregularities in the second 
column in those metals which have a small transverse effect need 
not surprise us. The three metals in which the effect is greatest 
are bismuth, where the greatest negative effect is found, antimony, 
and tellurium ; in the latter two the effect is positive, and in 
tellurium it is extremely great. Bismuth is at one end of the 
thermo-electric series, antimony and tellurium at the other. 
We see that metals with an extreme position thermo-electrically 
have a correspondingly extreme position as regards the transverse 
effect. Without at present trying to explain what the exact 
relation between these two effects is, let us consider how we can 
experimentally test whether or not the above general conclusion is 
justified in other cases. 
To do this we must examine other conductors, whose thermo- 
electric positions are at the extreme end of the series. Reference 
to a number of such, alloys and various minerals, will be found in 
the chapter on thermo-electricity in Wiedemann’s Lehre von der Elec- 
tricitcit. In the paper before referred to, the experimental arrange- 
ments and results with a number of alloys will be found. For the 
present purpose it is sufficient to give the table in which the results 
for the whole are gathered together. 
