1894-95.] Mr J. C. Beattie on Alloys in a Magnetic Field. 483 
than in antimony. Antimony and zinc, taken in quantities pro- 
portional to their atomic weights, give an effect which is not inter- 
mediate in value between those of antimony and zinc separately, 
but one which is much greater than in antimony ; and so on for 
the other alloys. 
Before comparing columns (1) and (3) we must note that the 
transverse effect is not in all cases a simple one ; for example, in 
the alloys of bismuth and antimony, bismuth-lead, the effect is 
certainly made up of two parts, one proportional to the first power 
of a given function, probably the magnetisation, and the other to 
the third power of the same function. The sign given in the 3rd 
column refers to the first of these, and we see that it is determined 
by the alloy’s thermoelectric position. 
So much cannot, however, be said about the numerical value : 
various discrepancies are to be found at the positive end of the 
series, but these are such as could be accounted for by a variation 
in the thermoelectric position. To answer this question it would 
be necessary to examine the thermoelectric properties in the different 
plates used, which, however, was not in this case attempted. 
If we consider the above results with those already obtained for 
other metals and alloys, we arrive at the following result : — With 
the exception of cobalt^ the simple transverse effect {Hall effect) in 
conductors has its direction certainly, and its magnitude probably, 
determined by the thermoelectric power of the conductor considered. 
ib) The Variation of Resistance. 
The modification of the Wheatstone bridge method, due to Lord 
Kelvin, was employed to measure the variation. The galvanometer 
reading for a given field strength — the bridge having been previously 
arranged so that no current passed through the galvanometer when 
the field was off — divided by the primary current, was taken as pro- 
portional to the variation of resistance. Unfortunately the per- 
centage variation was not determined. 
It is well known that in bismuth the variation of resistance is 
great, and it was found that in the bismuth-antimony alloys the 
variation was greatest in those alloys which contained the greatest 
