New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1892-02-03
A SCIENTIFIC MYSTERY UNRATELLED.

SCIENTIFIC MYSTERY TNRAVELLED.
Just why the magnetic needle, instead Of point
ing due northward, iuclncs TO one side to greater
or less degree. and why the region toward which
il is directed keeps shifting slowly, is a problem
which has for ages baflled the wscst men. But
a solution of IL which, if it is not accepted by
the scientific world as complete and final, at
least has much TO commend it to instant favor Is
now offered by Henry Wilde +. r. ;. It is briefly
discussed in Tho American Meteorological
journal for January by that new, though al
ready eminent, authority on Terrestrial Magnet
ISM Professor Frank H. Bigclow.
Mr. Wilde has come TO tho conclusion that the
outer she'll OF the earth and the great mass within
rotate somewhat independently of each other
The interior portion, still in liquid condition, he
concciycs as continuing to rcvolve about the axis
which our planet had in its infancy; that is, one
perpendicular to the plane Of the ecliptc. Some
how, in the great cataclysm in which the moon
was thrown OIL from the earth, the crust of our
globe was he thinks, skewed over TO one side
about twenty-thrce degrees; and this part of our
sphere, therefore, rcvolvcs about what we call
the geographical pole" The inner mass, like
the other planets and the sum- he regards electro
dynamic: while the shell is eectro-magn
Furthermore, two causes are supposed to render
those portions of the carth's exterior underlying
the oceans more highly magnetic than others ;;
the permanent 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
siructs n 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 correspond to
the oceans he attaches magnetized sheet-ron And
by means Of proper gearing he makes the inner and
outer spheres rotate on axes % IL degrees
apart Finally, for test purposes, he provides
for temporarily fixing a magnetic needle at any
point on the surface of globe. With this ingenious
apparatus, he declares he can reproduce every
known variation of intensity and direction in ter.
rcstria magnetism of which be can find a record :;
and what il the convincing feature of his eXper-
iment the real magnetic history OF all parts of
the world for the last four centuries far as he
can learn it, is actually repeated in the minutest
details when the inner sphere is made to fall
Iehind the outer one, in their revolution at the
rate Of 20 IL minutes Of an arc annually! That
exceedingly well-informcd and cautious expert. DR..
Charles A. Schott of the United States Coast and
Gcoietic Survey, tells Professor Bigelow 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 verifcatons Mr.. Wilde has presented, the theory
still holds good. The period Of time here required
for one whole secular" change is $50 years. which