New-York tribune., 1841-12-27
Reported for the New-Yerk Tribune
DR.. Lardner's Third Lecture.
Second Series
rpE ARTS AIDED BY SCIENCE.


rBE ARTS AIDED BY SCIENCE.
Ladies and Gentlemen When look back
at the progress OF the human race in the arts Of
civilization we are forcibly struck with the truth
tina, the sentence Of labor pronounced upon oar
first parents as the condition CT acquiring material
goods, was by no means confined to the lower ah'
animal wants of man; but that it has the same
imperious force as applied TO the sra'iilca''0"
his highest intellectual necessities. we seq
,rue, that Providence has supplied various ''''''
Of advancement to the human race but these ar
no, inns ,ersec,. az we find them, but are rather
.nsce,;he of receiving perfection from Inc sPPA-
c,t;on not of mere human endeavors' out Oh ttiose
b;,bsr movers of iateec:-the image OF himself
,yhicb God has stamped upon the mind OF man.
I, ia remarkable fact that whsn we cast our eyes
ground our world, we find man the most helpless
and de:encelcss of all the animal world. Some
Of the other animals are provided with covering
Of wool, feathers, &c. to guard them from the Vi
ci.,itudcs Of temperature; others have talons
claws. horns. or teeth to serve as weapons Of al
tack and others are swift, of foot keen Of eye or
quick Of scent, to enable them to make good their
escape from all that would annoy. In NJ an alone
Of the whole creation. do we find utter and tota
helrlessne.s Neither wool to protect him from
,t,o climate, nor feathers to guard him from the
all, nor any OF those defences with which otie'
aainals are furnished, belong TO him. And yet W
find this helpless creature King of the whole Crea
ton. How has he acquired this vast sscendancl
OYER all the animals so much more literally en-
lowed b. the simple power Of that noble intel
I.-t which distinguishes him from all other crea
ted beings on the face of the earth. We see in
every case where Nature has imposed the neccs-
si,y Of cxcrtlon, it has been done just to that de
gree which provokcs the operations of their intel
Iec,Gal power.
THE MAGNETIC NEEDLE.
In The early stages of civilization, when trailc
be;wer- different nations was narrow and confined,
ravira,ion was almost entirely coast-wisc and
made principally to countries not far removed anr
inhabitcd by people of not dissimar habits. Til,
property Of the magAet discovered
that when suspended freely it directed itself to the
poles and this became an instrument by which
the early powers ef navigation increased ana
the progress of civilization greatly aided and ud
vanced. /, was soon found, however, that this III
strument, put by Providence into the hands of man
was irregular in lis operation and that it could b.
usefully employed only by application of the intel
lect. 1t became apparent that the magnetic nee
die not only did not direct itself strictly to the
pole but that it not constant to any fixed Pon'
that ii was liable to continual variations depend
ing upon its place and other circumstances. Still
it was seen that it had a sufficient direction TO b.
Of essential service to the navigator and the il.
regularity which had been observed only stimulu.
ted TO action the faculties of the intellect.
1t was found that it did not point due North;
and soon after It's first adaptation to the purposes
nf the navigator was discovered, II was ut FIRST
supposed that its deviation from the true direction
was fixed and permanently the same and 1t wa,
thought that if tie amount of this variation coulc
be detected, all that would be necessary to its
rcction would be known. But on transporting j
10 different place. it came to be observed that it,
variation was governed by no known fixed law
but that it differed continually in different places
and that in using it mariners guide onl,
a rough approximation to the true direction coald
DO obtained Natural philosophers long sought
lay down upon chart these variations OF the com
pass, for every place upon the globe, so that the
variation for each place might be registered and
thus for ever known But no such chart eve
made of practical service; and resort was iinall!
had to- simpler rules By which from day TO day tn,
exact deviation of the Needle from the me.
rdan might be determined. There are many oil
these methods in USE and for the sake OF
illustration will point out
Suppose that the direction of the Needle, in h
ccrtan case, is west of the real north the man
ner in which the mariner upon the trackless ocear
would determine how far west it might be would
be this: -Certain rules supplied him by which
for every day in the year, he tell the Suns de-
cnatien,-its distance from the celestial equa
Tor; his own latitude he can easily calculate. h,
has the means then of telling the point in the hon
1vA at which the Sun will risc-and cua say how
many degrees ii will be on the meridian from III,
poc. Now suppose the angle of the Suns direc-
ton be 700 while the angle of the direction OF III,
Needle from the Sun is 65o; he knows that IN,
Needle varies D from the true north Thus after
making the correction he has the true north which
will continue the same while the Needle retain.
its variation, which will be moro or less according
TO the position of the ship the lapse of Tune, &c
This is laid down upon his log and carefully pre-
served, so that his direction may be always knewn.
The Magnetic Needle not only docs not alway.
preserve constant direction toward the north
but when suspended upon horizontal axis it will
rot hang in u vertical direction, but will St0sI
downward u certain angle. This fact was discuy.