Democratic standard. [volume] (Georgetown, Brown County, Ohio) 1837-1850, 1843-08-15
BY b. P. PALMER.
DR.. LARDNER's LECTURE ON THE
MOON


Of this eminent professor. Some of our
readers msydOubt some Of the positions
assumed by him in relation to the phys.
ical structure of the moon; but all will
admire the didas;ic simplicity with which
his views ore announced and illustra-
ted.
The Moon, he said, was a body of We
ryismall magnitude as compared with ma
ny Of the members of the solar system;
but was, 10 the dwellers on our planet,
'an object Of greater interest than any
ether-lbe Sun, alone, e4cepled-by rea.
son Of proximity--iis relations to the
earth.its importance to the theory of
gravitation and its various supposed and
real influences upon our globe. The OBJ
iect of ths astronomer was 10 ascertain
and establish facts; and in pursuit Of this
object, many erroneous notions and rdi.
culcus superslitions in relation to the
Moon and its imaginary influences had
been dispelled.
The Moon moved round the earth in
an orbit nearly circular, as was apparent
from the fact that her size remained the
same .be whole time.
The distance of the moon had been as,
certained by the usual mathematicaI
methods which are familiar to such as
had occasion to asc ertan the distance of
anac cessable objects. There were two
ways Of measuring distances-One was
the mechanical mode, that is, an aBpli>
cation OF the measure 10 the thing meas.
ured-as any body can see done by a
dry goods man, every time he measures
off yard Of cloth; another was by antap'
plicaton Of doctrines Of ratios. Toillus-
tate what this last meant, he supposed it
desirable TO find the distance, for exam
pie, Of lamp in frOntofthe stage, which
should be considered inaccessible. The
way to ascertain by the latter mode men.
toned, would beto observe it from The
two extremides Of the front of the stage.
The length of this front is susceptible of
admessurement by mechanical means,
and its length being once ascertained,
the two observations Of the lamp would
show the proportion between its distance
and the length Of the stage front. In
this way are obtained most of the long
distances on the earth's surface. In this
way the distances of the heavenly bodies
are established. A measure on the
earth's surface having been once ascer.
tained--the distances of the other bodies
can be shown TO bear fixed and definite
ratio of il.
These distances are usually measured
by diane ters of the earth, and in astrono'
mical language, ths Moon is said to be3O
.diameters distance from our Globe, or
100000 miles; our earth's diameter be.
ing 5000. This distance being known,
there is very easy way of ascertaining
its diameter. To determine this, you
have only to take 25 cent piece, an inch
across. Hold il before your eye, at such
distance as that it will exactly cover
the Moons disc aud no mole. This dis.
tance will be found to be. 10 feet. Now,
as 10 feet or 100 inches, is to one inch,
the 2 bit pieces diameter, so is the dis.
7 tance Of the Moon to her diameter; as
100 is 10 one, so is 24O 900 10 the an.
swer. The diameter of the coin, is hun.
.dred and twentieth part its distance and
the diameter Of the Moon is a enc hun
dred aud twentieth part Of her distance
Or2O00 miles.
OF the physical condition Of the Moon,
it may be remarked, that she has no lighl
other own, thsawhOle Of the light with
which she is supplied, being furnished
by the Sun. Her lineaments always pre-
sent the same appearance. they are
. unchanged, The same con6guratiOni
! now presented TO the eye of an observer
on the earth, have always been present
ed. The s'man in the Moon'' is an ole
A. saying. His size and shape were ascer
tained centuries ago, and the old gentle
men has not changed whit ia the inter
val. This shows, that the Moon alway!
keeps the same face towards us, and o
course cannot bo accused of wearing
two faces.
Again, the Moon has no atmosphere
This position is now pretty well estab
lished One means of so doiAg has beel
by observation Uf the occultatlon OF star
by this body. 1t is known principle
optics, that light passing through medI
Of different density will be refracted 0
bent out Of a straight line. This may b.
shown BY very simple experiment
which Is familiar to every school boy.-
Take an empty mug, and place in tn
bottom Of il piece of coin. Now, sta
tiOE the eye at such point obliquel
from and above the vessel, as shall a
low the edge Of the vessel TO interceE
and prevent view of the coin. Then
keeping the eye fixed at this point, le
water be poured into the vessel. Imme
diately, the object, hitherto hidden, be
comes apparent to the eye, although lh
place Of The eye remains unchanged
Nov this result follows from The fec