Year: 1864

When ball is discharged from a gun
and strikes an object, it is found that both
the ball and the object struck have risen
in temperature. II the force is sufficient
" great you cannot touch the ball, it is so
hot; and Just in proportion to the power
of the gun will be the heat Of the ball. -
Ef the power be sufficiently great, the heat
may be 80 intense as to bring ii t. white
heat and melt the ball. The mete0ric
stones that sometimes fall to our earth
nay be regarded aS balls, hut moving
With Much greater vc'ority They strike
against our atmosphere with so mnch
force that the force is converted into heat.
10 intense that they glow or become in.
eandescrnt. Suppose our earth, in its
resolution, struck against some opposing
Abject Ike a target, what would be the
consequence The force would be CON


Verted into heat. and the velocity is so
Great-twenty niles a Src0nd-that it
would he immediately brought to the
melting point. 1t would glow like the
sun, and bee0me luminous body. The


heat would be equal to that produced hv
the burning Of thirteen rqrthS made Of
coal. And ii v9uld then lalIinto the sun,
and would. by its loss Of momentum, pro-
duce heat four hundred times greater
than before, and it would he seen on the
suns disc as bright luminous spot. -
The force Of the earth Ealing upon the
sun wn,hd cOmniu icatr heat to the Sun
equivalent to the heat emitted hv the sun
in = century. 1t would serve MS n fuel
for that length of time. Now, the heat
Of the sun is mast probably due 10 this
source, the conversion of force into heat.
II Is probable that it is not combustion.
II the sun were composed oi coal,it would
last at the present rate only five Thousand
years. The sun. in all probability. is not
. burning but an il cndescrnt body. Its
light is rather that Of glnwirg molten
metal than that nf u burning furnace
But it IS impossible that the sun should
constantly be giving out heat, without
either losing heat or being supplied with
new fuel. We know the heat of the sun.
Each point is about thirty times hotter
than the furnace of Il locomotive, that is,
. square loot Of the suns surface gives
thirty times more heat than square foot
~ w a L NV lllHSS
OF the sun is 30 great that it would re
quire three thousand five hundred >nlar
systems, if made Of coal, to account for
the heat Of the sun. Assuming that the
heat Of the sun has been kept up by mt.
teoric bodies falling into 1t, and proof has
been given Of such fall, it is possible from
the mass Of the solar system To determine
approximately the period during which
the sun has shone as n luminary. On
boarding a steamer you can on examining
the hold for Goals, and ascertaining its ca
pacity, tell approximately how long she
has been on her voyage. Limits can be
set to the fuel Of the solar system, and
therefore limits can also be assigned to
the existence Of the sun as a luininarv. -
The limits lie between one hundred mill .
ions and four hundred millions Of years.


These are enormous periods, but still
they are definite The mass is 50 great.
and the cooling is SO slow, that, even on
the saPp6sition TINT no f,:el was atl,irri. it
might be Ave or six thousand years before
!, the sun cooled down single degree. i