Richmond dispatch. [volume] (Richmond, Va.) 1884-1903, 1888-03-24


were long enough 10 reach il and burn
his finger, 1t would take $50 years TO
transmit the feeling from his fnger-end
to his brain and enable him to feel hurt.
DIAMETER.
"The diameter of the sun is about
$50, 600 miles~A109 times the diameter of
the earth. The moon on O clear night
looks a good distance off 1t is about
240, ,0G0 miles away, or about a thousand
times as far as it is from here to Phila-
delphia. So with our largest telescopes
(say the one at Charlottesville with q
power of about 1000 the
moon looks as far away MS Philadelphia.
Z" If the sun were hollow sphere and
the earth were put in the middle of 1t,
the moon would be only about three
fifths OF the way out Of the surface Of
tue sun, so that the surface of the sun
would be capital sky for the moon.
BULK.
"Knowing the distance it is easy TO
calculate the bulk. 1t would take mil
lion and quarter of the earth to make
a ball as large as the sun. If the earth
were as large as n baseball the sun on
that scale would be twcnty-eight feet in
diameter. And yet it is only a little
star.
"But though the sun Is n million and
a quarter times as bulky as the earth, it
is only 800, 600 times as heavy. In other
words, its density, to use the technical
term, is only one fourth of that of the
earth, and it averages only about one
and one fourth times the density of water.
II would take us too far into the night
and into the subject to ascertain how We
this
at will suffice to say that we find it by
the distance (about sixteen
icet) that body falls in a second at the
sarths surface with the curvature of the
aaIth's orbit. Every year the earth de-
;cribcs its enormous orbit around the
iun, aud in order to do this It's path must
"a continually bent in towards the sun,
md the amount Of this bending is about
me ninth of an inch in second. This,
with the sixteen feet, gives us
he necessary dut0 for computing the
suns weight.
HOW FAST THE EARTH TRAVELS.
Have you ever thought how fast the
,arth travels in making this distance
Iround the sun? 1t hicsn nearly nineteen
niles in every second, and the swiftest
'annon-ball goes only a mile in four
econds, and it is as easy to see that the
'arth would overtake a cannon-ball in
he same fashion that a cannon-bAll
would overtake a freight train.
A WOMAN WEIGHING 4 TON.
"The weight of body on the suns
surface is about twenty-eight times as
much as it is on the earth, so that
ady who weighs one hundred pounds
would weigh over a ton on tho suns
surface.
"Ihe light that the sun sends us is
lbout fifteen hundred and seventy five
billions OF billions Of candle-power. It's
surface is about one hundred and fifty
lines as bright rs the calcium light, and
rom three to four times as bright as the
brightest part Of the electrical arc.
HEAT.
Gas to the heat Of the sun it is i'm
possible to speak of the exact tempera-
.ure. 1t is shown 20 be exceedingly
nigh by the burning glass. The burn
ing glass virtually moves a body at its
locus to the sun. but can never
produce n heat as great rs that
IF the sun. Lenses have been made
which virtually bring q bofy1t0 WITHIN
lj0.0 900 miles of the sun. In other
words, a body in the focus Of such a lens
IS heated as itwould be If 30, 600 miles
rom the surface Of the sun. Under
iuch circumstances pat mum, calcium,
and i'll fact every material,
nelts down at once. This, however,
loes lot give us the temperature of the
un. because it is not to be supposed
hat the different parts of the earth have
he same atmosphere any more
han all parts OF the earth have
he same temperature. Some parts are
lotter than others. But while We cannot
measure the temperature, We can mea-
ure the amount of heat sent out by the
un, which is an entirely different thing.
The calory or unit of heat is the amount
# heat that will raise the temperature
# one kiloPram of water by one
Iegree. Now, we find that at
he upper surface OF the earth's
atmosphere, when the sun Is vertically
'verhead, each square metre receives
rom % TO 80 of these Calorles Of heat
very minute, and since II calories a
minute are equivalent to one-hOrse
,ower, it follows that each metre of the
upper surface of the earth is receiving
II amount of energy equal to two-and-a-
lalf-horse power. We can put this
Expressing it by means of
he amount Of lee that the suns rays
7ould melt, We find that the amount of
eat received by the earth in one year
,ould melt 50 feet Of ice all over the
arth's surface, and if We can suppose
he sun to be frozen in and covered with
,e the solar heat would melt a thickness
( about. 90 feet in one minute.
WHERE DOES THE HEAT COME FROM?
GAS for an explanation of this heat.
ontinued the Professor, sit must suf /
ce tonight to say that it is not case
1 simple cooling or combustion. The |
leory that the suns heat is produced |
Y the fall of meteoric matter on the |
ln's surface is inadequate, and the best /
nd most satisfactory explanation is sug |
ested by Helnholtz, who in 1853 said it |
maintained by slow contraction of
le sun. An annual shrinkage of 250 |
,et in the suns diameter would account |
,r the observed fact.
"The only objection urged to this |
leory is that il il is true the emission |
{ solar heat must come to an end some
me.
According to Professor Newcomb,
le sun may be some 100000 years
ID, ana may possibly have future life
/ some 1000, 900 years more, consistent !
ith this hypothesis. But it is not i'm
ossible that some other causes of solar
lergy may not be ascertained.
THE SUNS CONSTITUTION.
The lecturer then discussed the con-
tuition of the sun, explaining the yisi-
lie surface or photosphere as a shell OF
Iminous clouds covering the great