BY W. H. GILDER. Author of "Schwatka's Search," "Ice Pack and Tundra,"
etc.
On the Fourth of July, 1879, after a long and tedious journey over
territory never before crossed by man, I stood with Lieutenant
Schwatka on Cape Felix, the most northern point of King William's
Land.
Looking in the direction of the Isthmus of Boothia, not more than
twenty miles to the eastward, across the frozen surface of McClintock
Channel, we could see the snow-covered hills of Cape Adelaide, radiant
with all the tints of the rainbow, in the light of the midnight sun.
It was there that, nearly half a century before, Sir James Ross had
located the North Magnetic Pole. The place is invested with deep
interest to all explorers, but, with us, the pleasure was mitigated by
the knowledge that we were entirely devoid of instruments with which
to improve the opportunity of either verifying the work already done
or continuing it upon the same line of research.
Ever since that time I have been strongly imbued with the desire to
return to that field of labor with a party of observers properly
equipped to make an exhaustive search through that storehouse of
hidden knowledge.
About three years ago I brought the subject uppermost in my mind to
the attention of Professor T. C. Mendenhall, Superintendent of the
United States Coast and Geodetic Survey, in Washington, and to that of
his assistant, Professor Charles A. Schott, in charge of the computing
division of that bureau. From the first both of these gentlemen have
been strong advocates of such an expedition.
[Illustration: COLONEL W. H. GILDER.]
"The importance of a redetermination of the geographical position of
the North Magnetic Pole," said Professor Mendenhall, in a letter to
the Secretary of the Treasury written at that time, "has long been
recognized by all interested in the theory of the earth's magnetism
or its application. The point as determined by Ross in the early part
of this century was not located with that degree of accuracy which
modern science demands and permits, and, besides, it is altogether
likely that its position is not a fixed one. Our knowledge of the
secular variation of the magnetic needle would be greatly increased
by better information concerning this Magnetic Pole, and, in my
judgment, it would be the duty of the Government to offer all possible
encouragement to any suitably organized exploring expedition which
might undertake to seek for this information."
Acting upon a further recommendation in this letter, the Secretary of
the Treasury requested the President of the National Academy of
Sciences to appoint a committee of its members, or others familiar
with the difficult problems involved, "to formulate a plan or scheme
for carrying out a systematic search for the North Magnetic Pole, and
kindred work," and such a committee was subsequently appointed, with
Professor S. P. Langley, Secretary of the Smithsonian Institution, as
chairman.
[Illustration: GENERAL A. W. GREELY.]
The work proposed by this expedition has attracted the attention and
held the interest of scientists everywhere, and material aid from
several scientific bodies has already been pledged toward the securing
of the necessary funds for transporting the party to the field of its
labors, and its maintenance while at work there.
The observers will be selected from among the officers of the United
States Navy attached to the Coast Survey, who have had special
training in magnetic field work. That bureau will also provide the
necessary instruments, but, in the absence of any appropriation that
could be applied to the transportation and maintenance of the party in
the field, the funds for that purpose have to be obtained by the
voluntary contribution of those with means and inclination to aid so
important an enterprise.
Said the late Professor Trowbridge of Columbia College, in a lecture
upon the data to be obtained by this expedition for subsequent expert
discussion, "We are living in an epoch in the world's history when man
is struggling for a higher and more perfect life, not only against the
degrading tendencies of his inherited nature, but to make the forces
of nature subservient to his advancement and well being. Among these
forces there are none which seem to affect or control the conditions
of animal life on the earth more than heat, light, electricity, and
magnetism, all, perhaps, the manifestations of one cosmical agent. As
the variations of the magnetic force appear to follow lesser and
greater cycles, it is not impossible that nearly all terrestrial
phenomena, which depend on causes allied to magnetism, follow similar
cycles. We can now predict the course of storms; may we not hope to
determine their origin and predict their recurrence, as far as they
depend upon the forces which have been mentioned? A knowledge of the
laws of the cycles through which these forces pass is the first and
only step in this direction to be taken, and this step must be made by
patient, long-continued observations."
[Illustration: PROFESSOR T. C. MENDENHALL.]
An immediate practical use of the observations to be made is their
application to the correction of compass errors. Every one can see
that such work as tends to render the mariner's compass a more
reliable instrument must be of immediate and direct benefit, not only
to the sailor, but to the surveyor on land.
Admitting that the observations of such an expedition as that to the
North Magnetic Pole will be of scientific and general value, it
remains to explain something of the personnel of the party, how the
work is to be conducted, and by what route it will reach the field of
its labor.
Besides the two observers of terrestrial magnetism to be supplied by
the Coast Survey, there will be a physician fitted by education and
habits of study to take charge of some scientific portion of the work,
in which he will be specially instructed by the Superintendent of the
Coast Survey or his assistant. There will also be three sailors
selected from the whaling fleet, who will have charge of the three
whale boats belonging to the outfit, and act as assistants to the
several observers. The writer of this article, by reason of his
experience in Arctic travel, will have charge of the expedition in all
except the scientific work, the reports on which will be turned over
directly to the officers of the United States Coast and Geodetic
Survey for reduction and discussion upon the return of the party from
the field.
The scheme of work has already been prepared by Professor Charles A.
Schott, who is looked upon as probably the best informed on all the
details of terrestrial magnetism of all men in this or any other
country. In the course of his exhaustive report upon this subject he
says: "The magnetic observations proper will comprise the measure of
the three elements, the declination, the dip, and the intensity, which
fully define the magnetic force at a place. The measures will be
partly absolute and partly differential, and will be considered under
two heads; those to be taken while travelling, and those to be
attended to at winter quarters." Detailed instructions for this work
are given which are too technical to be interesting except to the
specialist. He recommends that a single cocoon thread carrying a
sewing needle shall be used to observe the declination where by
proximity to the Magnetic Pole the horizontal force is weak. For it
must be borne in mind that the Magnetic Pole is the point where the
vertical force, called "dip," is greatest--represented by 90 deg.--while
the horizontal force, called "declination," is 0 deg.
[Illustration: DIAGRAM OF THE NORTH MAGNETIC POLE REGION.]
The observations for dip, naturally the most important of the survey,
will be made with a Kew Dip Circle employing two needles; the usual
reversals of circle, face, and polarity should be attended to at each
station, to place the instrument in the plane of the magnetic
meridian. The usual method of finding the plane of the meridian will
probably not answer in that part of the world for want of sufficient
accuracy; the direction of the magnetic meridian should, therefore,
be taken as indicated by the delicately suspended needle of the
declination instrument, and, where this method fails, dip observations
should be made in any two planes 90 deg. apart, of which the first plane
is preferably that of the meridian as guessed at.
It is proposed to charter a steam whaler to take the party from St.
John's, Newfoundland, to the northern part of Repulse Bay, which,
being directly connected with Hudson's Bay, is the nearest point to
the pole-containing area that is accessible any year. There a
permanent station is to be erected where regular observations will be
continued all the time and from which each spring a field party
(perhaps two) will start to locate the geographical position of the
pole.
[Illustration: PROFESSOR C. A. SCHOTT.]
It may be well to repeat that the Magnetic Pole is that point where
the needle of the dip circle is absolutely vertical--where it stands
at exactly 90 deg. to the plane of the horizon.
To find this unknown spot the observer follows as nearly as possible
the direction indicated by the delicately poised needle of the
declinometer. The magnetic meridian is not always a straight line, and
may therefore indicate a very circuitous route, but by a system
something like the regular approaches to a besieged fort one may be
certain of arriving there eventually.
For instance, when the needle indicates a dip of 89 deg. the stations
should be nearer together--say not farther apart than twenty miles, if
possible, and these intervals should be less as the dip increases.
Suppose the observer to have reached a point where the dip is found to
be 89 deg. 30', and at the next station he has 89 deg. 35', at the next
89 deg. 40'. At the next he may find only 89 deg. 37'; he then returns to
where he found the greatest dip and starts off at right angles, one
way or the other, to that course. As long as the dip continues to
increase, he knows he is travelling in the right direction. When it
again decreases he returns to the point of his last greatest dip and
travels at right angles to his last course as long as the dip
increases. In this way he will eventually see the absolute verticity
of the suspended needle marked and know he has reached the North
Magnetic Pole at last. Sir James Ross did not succeed so well, the
needle marking only 89 deg. 59' of verticity. But as this would indicate
that he was within one and a quarter to two miles of the point sought,
he was justified in feeling elated at his success.
It is believed, however, that with the improved instruments of the
present day, and in the light of our increased knowledge of
terrestrial magnetism, absolute accuracy is now demanded. These
observations will have to be repeated from time to time until at last
we shall know with certainty whether or not the North Magnetic Pole is
a fixed or movable point, and if it is found to move, the direction
and rate of that motion shall be positively determined.