New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1870-01-22
THE AMERICAN INSTITUTE.


Institute the Constitution Of the SUM-" The lecture
was profusoy illustrated by photographs Of the sum- re-
aected with the aid OF lantern upon background OF
white CLOTH One Of the Photographic showing spots and
facula was taken yesterday afternoon by MT Lewis NJ
Rutherford HIS observatory, and was pronounced p
DR. Gould excellent The lecturer was introduced
BY Prof Tman who announced that the last lecture OF
the course will be delivered Friday evening next by
Prof j. s. Newberry OF Columbia College. Subject "TDe
Colorado Plateau-Its Cahons and Ruined Cities
Dr. Could upon coming forward was greeted with APP
plause He said:
70 attempt any investigation OF the history OF
our early astronomical knowledge OF the SUM- Hero
Ao,us relates that Thales of Mlctus predicted the
total eclipse, which occurred In the year esA
n C. during the sixth day OF battle between
the Medes and Iydians and which by its awe-inspirng
,panepee brought their iye-years war to close We
tpow too that Pythagoras and his immediate pupils
Taught the doctrine winch he probably learned In Egypt
where he had studied that the sun is the center OF the
universe and that the earth revoyes around him once
wear Three and half centuries later Archimedes cor
reety determined the SUMS apparent diameter as be-
tween ~ and 49,.
The deteripatioplof the earths from the
problem Of peculiar importance, inasmuch rs 1t is
the unit in which, by Of KeppleTs laws all the
planetary distances are measured Consequently all our
knowledge OF celestial distances excepting only that OF
the mooL closely connected with the value OF this fun
knowledge which shows any adopted distance TO be
too large or too small demonstrates the same for all the
rest This determination is made by the same means
used by surveyors for detecting terrestrial nights and dis
tauces by measuringthe paIaax-i the difference OF
pons of view Mars and Venus, being the nearest TO
the earth offer the greatest advantages Tor
parallax, aud many observations nave therefore
been made Of these planets at two well
determined points, distant from each other on
the eartls surface The base line between tem pelhg
well known and the difference in direction IN which me
planet appears to the observers being carefully noted
Of Triangle which the distance of the planet
and thence eau deducted the distance Of the sun as
earth The actual distance OF the sun correspond
oO0 niles ana Since his apparent diameter this dis
taDco Is 81 81 somewhat more than han deGreel We
readily find corresponding true diameter TO be OF the
colossal represented by S6l232 statute miles This i
nearly 100 times that OF the earth SO that the earth
seen from the SUM- would appear but little more than
Il2OOO part large the sun appears TO us The Veo
cry oi I =. ~ s ,s AT the rate of is5 COO miles i'm
To form some idea of the stupendous distances, magn
tudes and velOcities with which we thus become ac-
quainted lie: compare them with some Of those with
ordinary rcbulet the would be represented the
same scale by glOOe OF II feet in diameter at distance
Of 30 rods; but denote the earth by an orange OF
size the sun would appear as sphere % feet III
diameter half mile oft We have seen that light even
with It's Uncomfortable velocity requires MN sec 10
traverse this enormous distance An electrical signal
travelling with the speed usual upon our telegraph wires
would put grdle round the earth in about ii seconds
yet 1t would require hour 80 min. TO reach the sum-
263s years in traversng the distance and could we
suppose iron bar TO extend from the earth to the SUM-
blow pull given at either end, matter how vio
lenty could reach the other extremity for more than
days although vibrations are transmitted throughIrOn
at the rate OF about ITO miles H9S3 metersJ in every
second The relative size Of the sun is represented On
the diagram which represents in true proportion the
disks OF the larger planets and the orbit of the moon
traced on a circle representing the face Of the sum-
SUNS
The suus distance and size thus being known, next
question has regard its weight mass it called
Uhan larry hoiie are NJ W.
abundant and trusty information and IL has proved
easier to weigh the than to his distance The
weight Of any terrestrial object is simply the attraction
subssting between and the EARTH being measured by
the force necessary to lift it, Now by Of large
Of metal other heavy material IL has Deen
found possible 10 exert measurable erayatye attrac
ton upon small objects, and comparison between the
exers and that exerted by the earth shown by the
weight Of the object itself gives us the actual mass OF our
planet In this way the mass OF the earth has been found
TO be little less than six sexuhons OF metric tuns of
about 2O5 avoirdupos) One moro step or the same
other heavenly bodies by the sun ana the earth respec
the very nearly 32 oOo times that Q; our planet
los times that of the earth His volume total size,
therefore is about ,2SOO0 times, while his weight is
must consist OF material fOuIfod lighter tue average
than that OF which the earth IS compOsed DIS spechc
gravity being on the whole about lSS times that OF
Since the attraction exerted by sphere is proportion
ate 70 It's divided by the square of the distance
from its center 1t is easily seen that the weight OF any
object the surface Of the sun must be 276 tunes as
great az the weight object the earth
Anything drop the surface OF the earth Will ta
l feet during the first second but near the suns
surface it Will fall than 44l feet during the first
second at the end Of the next 1t would have acquired
velocity equal 70 that Of cannon ball as II leaves the
most powerful gum and even n let Ian at the night OF
two miles 1t would this distance in less than
II was once thought that an exterior she'll surrounding
tho true body OF The SUM- the source Of his light ana
hest aud within this spell was comparatively cool
aa,k g1oy WniGn Noy that We know the case
20 be Otherwise aud that the interior OF the sun must pe
at temperature SURPRISING that OF the nercest fires
which eau be- produced by human the question Of
habitabty loses Its siguucance except perhaps from
theological pOiut of view.
But a consideration which might well have been borne
IN mind the vastly greater weight which all OBJECTS AT
iuIucusc mass A man Of ordinary size would there
Endorse the Younger Hersclels statement h" that no
weight" We must cOncede that II would he somew hat
tgiug exercise for him 10 run up and down STAIRS
very often and that the suns surface would be rather
hard road 10 travel
TIKI SUNS HEAT.
The sources of the light and heat of the sunthe only
two OF his properties apparent TO the ordi-
nary obeIysr--are problems Of the greatest difficulty
Iwn Only say here that the vivid light developed
by human art when interposed between the eye and the
cum appears like black spot upon the solar disk The
highest temperature yet produced by man is that evolved
by The combustion Of charcoal in oxygen, which Bunsen
estimates 10000 c. $4,000 J.; and this Is about hye'
eoycuhs OF lowest reasonable estimate for the tenn
perature OF the solar surface Coal DnhnS az te rae
of 10 the square foot IN abOn2 seconds would attain
this temperature and RanEne has estimated that m inc
furnaces OF powerful Locomotive engines, pOuhu oi
each square foot Of CRATE surface ls consumed III
from 80 to 90 seconds yielding neat from Ito 10 140 rs
Intense that at the surface OF the sun. . -.
Adopting s estimate that heat equal 10 mat elstted
BY the might be attained by the combustion OF coal
this rate OF OneDai pound per second 10 JUG squao
foot II Is easy to ud how long the whole mass OF the sun
would last were composed Of coal burning at that rate
aud furnished moreover with an unlimited supply OF
oxygen support the combustion. PERFORMING inc CAL