I 7 iquiries conceniing the Magnetum of the Earth. 123 
ed that ho other energy can be developed between two such 
bodies, the assertiori wiU need proof, and the proof will be hard 
to find. 
I reckon it possible, therefore, that by means of the mutual 
relations subsisting between the sun and all the planets, as well 
as between the latter and their satellites, a magnetic action may 
be excited in every one of those globes whose material struc- 
ture admits of it, — in a direction depending on the position of 
the rotatory axis with regard to the plane of the orbit. Each 
of the planets might thus give rise to a particular magnetic axis 
in the sun ; but as their orbits make only small angles with the 
sun’s equator and each other, those magnetic axes would, per- 
haps, on the whole, correspond with the several rotatory axes. 
Such planets as hav0 no moons would, on this principle, have 
but one magnetic axis; the rest would, in all cases, have one 
axis more than they have moons ; if those different axes, by 
reason of the small angles Avhich the orbits of their several 
moons form with each other, did not combine into a single axis. 
The conical motions by which the rotatory axes of the planets 
are carried round the pole of the ecliptic, (the precession in the 
earth,) joined to the revolving motion of the orbits about the 
sun’s equator, (which occasions the present diminution in the 
obliquity of the ecliptic,) might perhaps, in this case, account 
for the change of position in the magnetic axis. It would 
greatly strengthen this hypothesis, if the above great magnetic 
period, after the lapse of which both axes again assume the 
sarnie position, should .in fact be found to coincide with the 
period of the precession, which, however, seems a little doubt- 
ful.” 
Perhaps the Speculation just quoted, may seem more com- 
prehensive than profound ; it was given as a conjecture, and is 
nothing more. In fact, beyond the mere elements, the whole 
science is involved in conjecture, and after all that has been 
attemj)ted and achieved, we may still conclude, with a slight 
change, in the words of old Purchas, assumed by Mr Hansteen 
as a motto : “ This magnetical virtue was hidden to the gol- 
den and silver ages, her iron sympathie has long been known 
to the iron world ; but her constant polar ravishments, and her 
