The Vermont watchman. [volume] (Montpelier, Vt.) 1883-1911, 1892-02-17
A Scientific Mystery Unrayeled.

A Scientific Mystery Unraveled.
Just why the magnetic needle, instead
of pointing due northward, inclnes to
one side to greater or less degree, and
why the region toward which it is di-
rected keeps shifting slowly, is prob
lem which has for ages baffled the wisest
men. But solution of it which, if it
is not accepted by the scientific world
as complete and final, at least has much
to commend ii to instant favor, is now
offered by Henry Wilde, F II. S. 1t is
briefly discussed in the American Me-
neurological Journal for January by that
new, though already eminent, authority
on Terrestrial Magnetism, Professor
! Frank II. Bigelow.
Mr.. Wilde has come to the conclusion
that the outer shell of the earth and the
great mass within rotate somewhat in
! dependently of each other. The inte-
| rior portion, still in liquid condition,
| he conceives as continuing to revolve
about the axis which our planet had in
its infancy; that is, one perpendicular
TO the plane of the ecliptic. Somehow,
in tie great cataclysm in which the
moon was thrown off from the earth,
the crust of our globe was, he thinks,
skewed over to one side about twenty
three degrees; and this part of our
sphere, therefore, revolves about what
we call "the geographical pole" The
inner mass, like the other planets and
the sun, he regards as ectro-dynamic:
while the shell is electro magnetic.
Furthermore, two causes are supposed
10 render those portions of the earth's
exterior underlying the oceans more
highly magnetic than others; the per-
manent low temperatures at the bottom
of the ocean, and the greater amount of
iron here included, the crust being
thicker under the seas than elsewhere.
| For purposes of demonstration Mr..
Wilde constructs machine, consisting
of one sphere within another slightly
| larger one, both converted into magnets
by coils of wire encircling them. Upon
those portions of the shell which cor
respond to the oceans he attaches mag
netized sheet-iron. And by means of
proper gearing he makes the inner and
outer sphere rotate on axes 235 degrees
apart. Finally, for test purposes, he
provides for temporarily fixing a mag
netic needle ut any point on the surface
of the globe. With this ingenious appar-
atus, he declares he can reproduce every
known variation of intensity and direc-
ton in terrestrial magnetism of which
he can find a record; and, what is the
convincing feature of his experiment,
the real magnetic history of ali parts of
the world for the last four centuries, so
far as he can learn it, is actually re-
peated in the minutest details when the
inner sphere is made to fall behind the
| in THAR raupl,tinn ot tho
rate of 224 minutes of an arc annuallyt
cautious expert, DR.. Charles A. Schott.
of the United States Coast and Geodetic
Survey, tells Professor Bigeow that he
has records of magnetic variations of
which Mr.. Wilde is evidently ignorant;
and that when these are used as tests,
in addition TO the vast number of veri-
fcations Mr.. Wilde has presented, the
theory still holds good. The period Of
time here required for one whole "sec-
uIar" change is 900 years, which agrees
with the values OF Sir William Thorn
son, though differing somewhat from
tradition.
The only doubt which will remain in
any scientific mind regarding the
soundness of Mr.. Wilde's explanations,
after studying this magnificent demon
stration, will probably spring from the
notion, now widely entertained by
physicists, that the earth is solid to its
core. Sir William Thomson has ex-
pressed the belief that the whole globe
is as rigid as glass, if not as firm as steel.
Yet Mr.. Wilde declares himself thus
confidently: From the various move
meuts of the declination and inclination
needles, correlated with eacn other in
direction, time and amount, on different
parts OF the earth's surface, the theory
of fluid interior may now be consid-
cred 10 be as firmly established as the
doctrine of the diurna rotation of the
earth on its axis "-NeU York Tribune.