Richmond dispatch. [volume] (Richmond, Va.) 1884-1903, 1894-04-29
Noyement of the North Magnetic foIe'
CEDAR BLUFF, VA.
70 the Editor Of the Dispatch:


TO the Editor Of the Dispatch:
At what date did the Norih Magnetic
Pole begin It's present westward move
mcnt, and when viii 1t begin moNlnH
east again? Please answer through the
columns Of your paper and oblse.
Yours very truly, >. n H.
Captain Baylor. Of the state oyster
Ground Survey. answers this question at
our request. and as follows;
The line Of mo variation" which runs
through the North Magnetic Pole mas
been moving westward ever since the
discovery of the continent, and since
Trustworthy observations have been re-
corded
Tho line Of no variation is the line along
which the mean direction OF the compass
needle. for twcnty-four hours, Is norm
and SOUTH. G.. in the direction of the
axis Of the earth East of this line The
variation is west Of north; west OF IT,
east OF north. In oregon, for instance.
the variation is as much as 20 degrees
east Of north and in Maine as much as
- degrees west Of north.
The line Of no variation IS known to
have shifted from position east of New
York city to its present position, which
is west OF Charleston. :. c., ana OF
Detroit. Mich. How long this great move
ment viii take place. from our present
knowledge of terrestrial magnetism, we
cannot predict with certainty. The Varia-
ton has been increasing east Of the line
Of no variation until quite recently.
In Nova Scotia the needle is now almost
stationary, and is commencing TO move
eastward. This effect will gradually eX-
tend itself over the United States. and
steps and move eastward.
In Paris, where reliable observations
have been recorded for several hundred
years. the % Rod was found 10 have been
over 400 years.
The magnetic conditions of the east are
being investigated as never before. The
Intensity Of the earth's magnetism, the
variation of needle. and the dip of the
needle are being recorded night and day
in fixed magnetic obsorVd tories. The
writer has himself investigated the con
ditOns of the earth's magnetism at sta
tons distributed throughout Canada and
the United States.
As matter of local interest, 1t may be
interesting to note that throughout Nir-
ginia the variation is now west Of north,
with an annual increase Of about 3 l-3
minutes Of arc Three and one-thrd min
utes of arc will produce an error Of five
feet In the position Of n corner on a line
one mile in length. For longer period
than one year and for "a greater distance
than one mile the error would be pro-
portonally greater. In addition 10 this
annual variation. the needle has Il daily
variation. In Virginia the north end Of
the needle Will. during the summer
months, often point rs much as 70 minutes
of arc nearer the east at \. II. than
at y. Nj. SO that a surveyor with per-
feet compass. may find in the same line
one mile long an error In the position Of
corner as much as ~ : feet. IL ne
traced out his line AT Z 4. NJ. and re-
traced ii at l 7. NJ. and on the same
day.
This proves that the surveyors com
pass Is not an instrument OF precision,
and as the fixed stars are the only per
feet timCkcepers so are they the only
safe guides In determining a true di-
rection. j. b. BAYLOR.