Vermont phÅ“nix. [volume] (Brattleboro, Vt.) 1834-1955, 1866-11-30
For The Phoenix
Variation of DcclinatiOn.

Columbus observed with intense anxiety,
while navigating an unknown ocean, Il de-
clination in the relative position of the mag
netic needle of his compass. Hitherto and
even now the uninitiatcd believe the same;
the needle was supposed at every longitude
to constantly point due north. By the mar
iners the declination was apprehended to be
an ineXplicablc mystcryla y nor is it solved
to-day-the mystic fact remains, though the
cause is unfound. But it is not prudent to
affirm that what never has never Will be
discovered: or what has happened will hap
pen always in like manner; nor to say with
a writer, thirty years since, that "lhe polar
ity of the needle. with its variations and IT,
regularities, is a hidden mystery which is
never to be searched out by man." Modern
science disproVes the assertion. And the
Atlantic cables demonstrate an operation,
which, if foretold in Columbus's time, that
that would be done in as few minutes as he
was months in traversing the wilderness OF
waves, would have been deemed more than
miracle. Yet observation and experiment
the basis of practical science, have reduced
to practice and shown results which enable
the mathematician to derive rules for regu-
lating with good degree of accuracy, his
measurements of lines and angles with the
compass, which although not perfect in
strument, is always convenient and seldom
very wrong"
A very few declinations of the needle arc
as follows: Paris in 1880, II deg. 30 min. Z
1866. deg: 1914. % deg. 81 min. W; 1853
20 deg II min. W. Angle of Maine, 1866
% deg W: annual change, min. sec.-
Cape Ann, II deg. W; Boston, IL deg. q
mil. W; Cambridge, Mass. II deg. II min
W: annual change, min. Hanover, n. IL.
II deg. 81 min. W. Annual change at Ches-
terrified, n. H., 6 min. 4 sec. Westminster
VT, deg. w; annual change, I min. 30 sec
SaXton's River Seminary, VT, 10 deg 5U
min. W annual change, Smin. 80 sec. New
| fame, VT, deg. 30 min. W; annual change
min. Hartford, CT, 0 deg. s min. W; an.
nual change, min. Burlington, VT, II
deg 80 min. w. New York City, 6 deg. "a
min. 3G sec W; annual change, 3 min. 6 sec
Philadelphia, 3 deg. 26 min. - sec. W. De
troit, II min. E; annual change, min. st
Louis, 0 deg 30 min. Is sec. E; annual
motion, min. sec. Washington Terrific
ry, 2l deg. ID min E; annual change, moi
very far from | min.
The polarity of the needle is a fruitful
subject for investigation and analysis; fol
even llS lTIcguldrlllCS Stcll regular, anu
there appears to be period in which, hav-
ing departed its maximum, it returns regu'
larly, passes ON TO the other side of the true
meridian, etc, GtciWO. But it is observable
that it moves most rapidly towards its at
trahent when near the meridian on either
side yet in its courses, it compasse'
complete arc, and, as shown above, de-
monstrates the truth of Boscovich's theo
ry, viz: "That any variable quantity, whls
it passes from one magnitude TO another
passes through all the intermediate magni
| tudes of the same kind. That to every par
ticular instant a particular state CORE
spends"
The methods Of determining the annua
motion of the needle, owing TO its imper
ceptibleness, and requiring as it does a Sc
ries of years for its ascertainment, are NOR,
tedious than those for finding the actual de
clination, which can be derived from sin
gle observation upon the north polar star
| (Cynosure0 or by comparing the compass
with some known meridian mark; which, i
is wished, might be established by law il
every town, so that the surveyor could read
lily note the needles declnation, which. fo
convenience of future reference should b
noted in every survey taken with the com
pass. d. L. a.
Fayetteville, VT.