98 Col. Gibbs on Magnetism. 
or has the most attraction to matter. But there are other 
rays, which Herschel, who some years since discovered them, 
calls invisible rays, which are still more refrangible, are next 
beyond the violet, when refracted, and partake of most of its 
properties, except that they are invisible. I have not yee 
seen any account of the experiments of M. Morechini, other 
than the notice in the journal ; but I trust I shall soon be able 
to determine whether those invisible rays do not possess the — 
magnetic power as well as the violet; or, perhaps, possess 
exclusively. , 
As the refraction of the atmosphere in the polar circles, is 
at least ten times greater than in the tropics, a greater quan- 
tity of the magnetic rays will there be separated. and combined 
than elsewhere; and of course arises excess of magnetism 
Hence the direction of magnetic bodies towards the northern 
and southern extreme regions. ‘Fhe great absorption and 
emission of light in the polar regions, by the ice and snow, 
may cause the extraordinary illumination of that country during 
the absence of. the sun, and the emission of the magnetic ray 
with electricity may, perhaps, give us the aurora borealis. 
e coincidence of the diurnal variation of the compass with 
the solar influence, deserves particular notice, and will have 
considerable weight on this subject. 
That there are many facts which cannot readily be explained 
by the theory of light, I shall not deny; but in the infancy F 
this system we may be allowed to hope that future observa 
tions may enable us to remove present difficulties. One thing 
must be admitted, that no theory has heretofore been published 
peawe ea hicee ces 
relating to magnetism, which has’ received, or seems entitled to 
much confidence. In your next number I hope to be able 
to furnish you with further remarks on this subject 5 but, F 
have no doubt that philosophy will finally determine that _ 
owe to the solar ray, light, heat, electricity, and magnetism. 
G. GIBBS. 
Sunswick, January, 1818. 
