169 
made in the University of Utrecht. 
must be carefully removed from the place where both metals are 
in contact. If the end of the bar of antimony turned to the 
north is heated, the deviation of the needle is westward, but 
much less than when the conjunctive slip is copper. By these? 
experiments Professor Seebeck's statement is* we presume, fully 
confirmed. 
6. It thep became necessary to inquire, whether antimony* 
alone would act in this manner on the needle* or whether any 
other two metals, joined in the same manner* would produce 
similar effects^ After some trials, the following apparatus was 
adopted. A thin slip of red copper, of one-fourth of an inch in 
width, and a similar one of zinc, were bent, as in Fig. 10, CD* 
being about 8 inches in length. The ends of the two metals were 
rivetted together at A and B, and the whole placed in the mag- 
netic meridian, and a needle in E. A spirit lamp was applied 
to the end B, turned to the north, and the needle deviated 10° 
to the west. If the whole was suffered to cool again to the tem- 
perature of the atmosphere, and the lamp was applied at A, the 
needle would deviate to the east. 
7. The apparatus being inverted, so as to have the zinc above 
and the copper under the needle, then on heating the part B, 
turned to the north, the deviation was 10° to the east. 
8. The experiment was repeated with silver and zinc, instead 
of copper and zinc, as in Fig. 10. 
The apparatus being thus situated, the deviation was to the 
East , if heat was applied to the end turned to the North ; and to 
the West, if applied to the end turned to the South. 
9. It was thus evident that the property mentioned by Pro- 
fessor Seebeck, is not restricted to antimony, but that other me- 
tals, properly disposed, will produce the same effects* General 
Van Zuylen then suggested a different way of applying the 
heat, and causing the deviation of the needle, by which means 
the effects were rendered more striking. Slips of copper and 
zinc were disposed as in Fig. 11. The two ends of both metals 
were coiled up together, so as to form a spiral of several turns. 
This spiral was immersed in a cup containing water; and the 
whole was placed as in Fig. 11. The needle was set upon the 
zinc. Sulphuric acid was then poured into the cup, and the 
needle deviated to the westward as much as 50° or 60°, and some- 
