Morning herald. [volume] (New York [N.Y.]) 1837-1840, 1840-12-15
MAGNETIC seicnce-Loekc's Lecture !.

also in norton Of what is called respectable society
in New York.
Magnetic seience-Loe ke's Lecture.
Mr. r. A. Locke delivered the first lecture Of his
coarse ON Terrestrial Magnetism at the Rooms of the
American Institute in the Park last week The lee
ture was well attended, and was clearly illustrated
by diagrams.
Mr. Locke be gan by observing that the subject of
Terrestrial Magnetism was one OF the deepest inter-
est to every American. The successful study of 1t
was certain to advance the interests of that Raton,
or individual, who pursued it. With this end the
nations of Europe had already engaged extensively
in the prosecution Of it; they were, and had been
for time directing al their wealth, talent aud
energies, with view to increase their knowledge
of terrestrial magnetism, and to elevate it to the
rank of exact science; and to be enabled to cacu
late all its data successfully and accurately,
we now made calculate ions in the science of astro-
nomy.
Although terrestrial magnetism had scarcely
reached that point where it could lay claim to the
dignity of place among the sciences, yet its opera
tons had been known and noticed as far back and
farther than had authentic date TO guide US
in history. The antiquity Of the magnetic needle
was known to all Ii extended as far back as 100
years the Christian era then it found to have
been known to the Chinese; from them was traced
back to the Hadoos; then through one or two other
nations back again to the Hndoos, from them to the
Persans, and hey ond them il is lost in oblivion.
1t seems strange that knowledge Of the prnci-
Piles of magnetism has not been obtained before this
Its operations aud effects seen in mining and
they are seen in the motions OF the stars The sa-
wage nations knew OF the existence OF magnetism In
minerals and have operated thereon, withOat posses
sing much scientific knowledge. The calculations
relative to the made by the ancients all ba
sed upon the connection which those motions have
with that magnetism which pervades the whole uni
verse and which is rendered evident to by
sensations
The declination or variations OF the ghetto nee
de- as they are called, have long been noticed, and
written Of as being sometimes to the west Of north
and south, and sometimes TO the east OF north and
south. The dip Of the magnetic needle, as IT is
termed, has also long been observed But still
great and valuable progress has been made by scicn
tifc men general towards accounting upon scien-
tfc principle for those variations and the dip OF the
needle, nor for calculating accurately the progress
and data Ct those variations. We have dignified
tronomy with the rank Of an exact science; although
the and variations Of the heavenly bodies
were once thought % be as mysterious and incom-
prehensiblc as those Of terrestrial magnetism And
whv should we not be able to calculate accurately
the ements connected with the latter Is it not
an elementary principle which we find extensively
in operation through all the works of nature. And
al nature and all natures elements are perfect and
controlled by certain immutsble laws there is
the refore ertanty in regard to the move
ments and operations Of terrestrial nagnet,m than
there is to the walk Of the stars through the lofty
vaults of heaven.
Mr. Locke then paid very handsome tribute to
DR. Sherwood whom he termed the discoverer of the
true principles which egulate terrestrial
and then observed that the theory of Dr. HALEY that
there were two poles in each hemisphere, and one
termed the magnetic pole, had long been known To
all But that the whole principle Of the laws of all
Mating forces were discovered by Kepier when
he laid down the rule OF the inverse squares of the
Magnetism is the parent Of all forces; Of those that
regulate life, cur whole being the movements Of
our limbs the circulation Of blood and the acute
Of all our sensations under all circum stances II
we stand in any particular latitude and longitude,
say that OF New ork, and watch the movements Of
the ma gneie neeols, find that the needle after
rv ing at direction where IL points due north and
south, varies from that position and runs from East to
west; In this progress declines to the west after
il reaches certain point to the west, il does not
any farther west nor does ii Immediately run back
to the east but it pauses awhile. This fact has
yer been accounted for and has occasioned great
c sion in all calculations the subject which
perhaps would have been obviaed If the persd bad
been accounted for in which the needle appears TO
remain stationary.
IL has also been observed that Will this dec lima
I ION OF the needle has been going from east TO
west, at the time il has been ascertaned that
the needle has begun TO decline from horizontal
position, or apont Of no angle, until it rested at a
certain determnste angle with the horizon; this is
called the " dip ofthe needle, and is very different
in different places the earth The apparatus BIZ
which this ascsrtaned has been called the dipping
needle, in which 1T has been supposed that the nee
die points directly 10 the magnetic pole Of the earth
There is point zone, near tho terrestrial equator
however where the needle has no dip at all; but as
general rule, on the terrestrial equator the magne-
To the north 81 thi. magnetic zone or equator. |
that extremity OF the needle which Is charged with
hat is termed the austra gnetism declines from
the horizontal; and to the south Of the magnetic
equator, that end Of the needle charged with borcal
gpetsm declines. And the poles OF the earth and
Of the needle have thus been considered the centres
Of acnon OF the magnetic forces.
The magnetic equator has been found TO lie at a \
ertan angle with the terrestrial equator but these
lines also found To be double aud TO each
other in different positions. So. also, great difficult
ty has been experienced ia determining the line of
no variations, which ha, been said to be the most
tortsous cf ALL All this has caused great confusion
In the calculations Of scientific men; and has caused
the various nations Of Europe to send out expen.
sive expeditions TO test all these things and 10 ar
rive at correct data and definite cone ions; as to
whether this line Of variation 10 dire line, and
can be relied on as certain guide for determining
the latitude and longitude.
The syste u which has generally been pursued in
all these expeditions, has been very good for pur
poses on a small scale. But the thorough and |
searching observations OF the deelinstion Of the
needle, have bees tso much neglected for those Of
the magnstic forces OF certain local spots which
are always operated upon, more or less by certain
local attractions. And IL would have been much
better in all those instances to have attended the
regard to the general direction of the great magne
tic forces.
In course OF lectures 81 this nature to mixed
audience, OF coarse, the first must be q very elg-
mentary one. What | purpose demonstrating in |
these lectures 10, that al the principles and
ments conneotcd with magnetism can be czlc usted
and defined az CLEARLY as those OF any OF the sci
ences with which VIC are most familiar DR. Ross
crossed the magnetic equstsr in Iss5, in latitude
II deg Jm.; and making allowance for the time Of
year, this vas the exact spot 1t whish DIR. Sher-
wood had calculated IL would be fossd. And BY his
system we calculate accurately what the varia-
tons Of the needle have been in all tne past; and
what they will be IN all time 20 come. We can give
predictions cf variations and loustudes, eslculs ed
upon those variations, for any time or place; and
they will be found correct, as tested by ob.erva-
tions Of the sun with transit instrument.
In all the phenomena connected with this wonder
ful and delightful science there sre no errors-no
discrepancies! All the parts of the machinery
work with truth and accuracy knewp only to the
ahtx rnzchinerx af naaure- For The 40 called