New-York daily tribune. [volume] (New-York [N.Y.]) 1842-1866, 1848-01-27

....Coscluc 81 hea>etioIs.
This distinguished Astronomer vss greeted iGst
evening by large and highly intelligent audience
who manifested the deepest interest gbout his
Lecture. He spoke as follows
LADIES AsD GESTLExES. Already have learned
enough Of America to know how needless it is
that a visiter from Great Britain should begin an
intercourse such as propose 20 establish here with
anything merely spol0getic ior believe that these
two nations resting the opposite sides Of the At
antc 10 whatever discussion OF minor interests We
may be severed, still neither Of as inclined
70 forego the privilege derived from our common
language and also a common, and surely may
say an illustriOus ancestry, Of union ia the grand
tssk Of exploring through the mGzes OF creation
the mighty ordinances Of God. and Of c)ntem-
plating together, for a moment. the deeds Of
those who have striven 70 unfold them. Con
fdent then, OF an entirely kindly reception
confident that may almost drUp tuv name Of
stranger. / would now venture 10 bring before you
some Of those cOnte mplations which are pressed
upon US by a consideration OF the laws which gov
ern the great Universe in which we are. would
venture that we cast our eyes for r while upward
from the Earth. toward that dazzling array OF stars
which bursting forth as the lominary Of day de-
clines, summons Us 20 the contemplation OF those
vast infntudes in which they are.
1t lis my wish during the presen. lecture, 20 pass
with you upward from these confines Of our Solar
system toward tina, grand congeres Oforbs OF which
our Sun is the center, and 20 trace among these II
we can marks Of that order and system which
Indicate % US as do althe phenomena aroundus that
We are here amid an Intelligence which preserves
them even as at first created IL isnot certainly
natural when one considers the depths AZ which
these stars ie the impossible character OF the CULTS
which separate them from our Earth that even at
the threshold Of the inquiry, We should be met by
an uDbeef in many respects, whether or not we
can reach them, or, ut all events be able 70 carry
there precision Of view, without which perrns-
hence Of understanding regarding their arrange
ments can well be discerned- On which account
permit me- in the first place briefly TO place before
sou the principle on which these great instruments
have obtained the power 10 which we owe
knowledge of these remote realms OF Space.
would for one moment. ladies' and gentlemen, pre-
yious 10 entering upon the subject, request your
attention to the character Of that great telescope
power which has enabled us % pierce beyond the
confines OF our own system, and examine those
mighty orbs which fill the boundess realms Spacc
beyond it. The telescope IS not simple instrument
but when we look at It with regard u Its more sim.
ple elements we see at once, and clearly. how 1t
enables us 20 20 into these great proundities We
find that when one views with the naked eye
distant object. the power OF vision is dependent on
one plain and very distinct circumstance. II is
this We find that the power OF vision cannot be
made sensible unless the light that comes 20 the
quantity or density There be little doubt
that however far away the brilliant object Is, II It
is sending forth light through all space that light
must reach every nerve which is capable OF recev-
ing il but still unless 1t reaches the human eye
with sufficient power. density or Intensity II
will not enable that eye TO have the sensation OF
sight or vision.
Suppose for instance, We have brilliant point
A, as thus
sending out light through all Space wherever an
eye is placed capable of receiving light from that
brilliant point, it must inevitably receive rays from
that point in other words. II must be acted upon
by that point toreceise tie accusation VI VISION
It is so with regard to the human eye. Unless
certain density Of light enters T. the sensation oil
vision will not be preserved Notwithstanding
what the distance of the object may be, light must
enter into the eve from that object. Suppose, Tor
instance, the eye is placed at 1; the ilsht coming
rom the object A. being dispersed through space
will necessarily be less than the light at b. and
while the light NJ Is definite, distinct quantity,
the light received by an eye at may not be
at ali sufficient 10 operate upon the nerve
so as TO cause the perception OF vision Now then
supuosng that when the eye 81 10 preSentedt 20 the
brilliant point A. that that point is merely sending
forth quantity Of light sufficient TO cause the sen
sation ollight and nothing more, what would We
require 10 DO in order 10 make this point or star
brighter tnan il naturally Is IL seems 10 me We
would require 20 make the light coming from this
star more dense than i. appears to be when IN lis
natural state. Now, the point Is, how can THIS be
donel How can We, oy means OF any art or SCI
ence place the eye in such relation 10 tue star,
that il shall view greater quantity OF light than It
nsturallydo There s principle IN optics which
comes to our aid, of a very plain and distinct
kind and which think the audience wall az once
understand. Suppose that We place at b lens,
piece Of glass shaped that when the rays OF
light pass from the star or the brilliant object A,
&, hall No lnnppr their
rectiinear course but shall be caused by the lens
to converge and fall upon the eye at {. The au-
dience will at one perceive that the eye at L IL
altogether in new position. Instead OF receiving
merely faint dim ray Of light. It Is now receiving
a great clear and strong ray OF light formed by
the concentration by the lens oil the numerous
rays Of light which previously were dihused
over a large surface This IL the principle
upon which the telescope acts IL collects the
scattered RAYS Of light and causes them TO fall
upon the eye in the manner OF the lens as Just des
cribed Let US see, then, what must be the power
ofthe telescope as compared with that oil the eye.
II simply this: II We have placed between TIE
eve and an external object, any great lens, We
will see that object with an amount Of lght Just
az much greater as the lens through which we are
viewing IL il greater than the pupil OF the eye.
Now II seems to me that. II We understand TINS
very simple principle, the great power oil me tee
scope can be easily and at once sscertalned- sup
tislileo-that little, simple telescope with which
he first attempted to make his way In the hea-
yens. We find that il Is but little more than
an inch In diameter. Yet still, when We com
pare the surface Of light which that inch neces-
sarlly met wi h the quantity OF light falling from
any object upon the pupil OF our eye, one cannot az
all marvel that we should be able 10 see through
comparatively small glasses, objects situated a.
great distances with very remarkable dlstinctness-
Until comparatively recently, the telescope had
not at all reached the great power which II now
possesses The instrument recently used by
Us. was perhaps one whose object glass, or MIR
ror was not larger than eighteen inches N d.
ometer This was the one by which Sr WI
han Herschel was enabled to make his grand
5iscoveries. Recently however, we have con
structed instruments OF mach greater power The
vast telescopes Of Lord Rose have reacned the
diameter OF four and even SIX feet Now, II the
audience will for a moment consider the immense
surface OF mirror Of six feet IN diameter COM
pared with the surface Of the pupil Of the eye
/ think that il will not DO al al marvellous
70 them that the power OF these telescopes
should be so enormous rs has been report
ed. The telescopes OF Herschel, which were
about eighteen inches in diameter, possessed nine
~ five times greater power Of penetrating into
S,,ra than the naked eve bat the power OF tee