Mr. Halliwell on the History of the Inductive Sciences, 461 
all appearance perpetual. I thought for some time it might 
be possible to procure similar perpetual currents, by com- 
pound thermo-electric arrangements. Fig. 8 will serve to 
show the character of these combinations, and also the cause 
of their failure. Let «, b, c, be wires of three different metals 
soldered together so as to form a triangle. Now if these 
metals were selected, so that a and h could form a more 
powerful thermo-electric pair than a and c, or h and c, it 
might be expected that at all temperatures an incessant cur- 
reru would run round the system. Such, however, will not 
be found to be the case. In effect, any one of these three 
serves simply as a connecting solder to the other two, and 
hence no current is excited; for the ends that have the third 
metal between them, although that metal intervenes, are un- 
der exactly the same condition as the other ends which are 
in contact. 
5. Thermo-electric currents, evolved by pairs of different 
metals, do not appear to differ specifically. As different gases 
durino- combustion burn with differently-coloured flames, and 
as different sources of caloric evolve rays of heat which are 
absorbed differently by different media, it might be expected 
that a pair of wires of copper and platina would give out a 
current of electricity unlike that of iron and palladium. I have 
made many trials on this point, adjusting a wire of copper and 
one of lead to each other, so as to stop equal quantities of 
electricity flowing from a pair of copper and platina, the 
galvanometer needles being brought to the same point, 
whether the long wire of copper or the short wire of lead 
was employed. But, in the case of every combination which 
I tried, these two wires acted alike, nor could I ever evolve a 
current which would pass with more or less absorption along 
the lead than along the copper. 
LXVIII. Illustrations of the History of the Inductive Sciences, 
No, I. The Reception of the Copernican Theory in England, 
By J. O. Halliwell, Esq.^ F.R.S., F,R.A,S,, F,S.A,^ 
M.R,S.L., (^rc, of Jesus College^ Cambridge J 
^ I "'HE most zealous reader would not require, nor the most 
enthusiastic inquirer expect, to find the results of new 
and deep antiquarian research in so comprehensive a work as 
that by Professor Whewell on the History of the Inductive 
Sciences ; much less would any one for a moment consider 
the credit of that eminently distinguished author in any de- 
* Communicated by the Author, 
