286 FRAGMENTS OF SCIENCE. 
of coal. How much greater must be the heat developed by 
a body falling against the sun! The maximum velocity 
with which a body can strike the earth is about seven miles 
in a second; the maximum velocity with which it can 
strike the sun is 390 miles in a second. And as the heat 
developed by the collision is proportional to the square of 
the velocity destroyed, an asteroid falling into the sun 
with the above velocity would generate about 10,000 times 
the quantity of heat produced by the combustion of an 
asteroid of coal of the same weight. 
Have we any reason to believe that such bodies exist in 
space, and that they may be raining down upon the sun? 
The meteorites flashing through the air are small planet- 
ary bodies, drawn by the earth's attraction. They enter 
our atmosphere with planetary velocity, and by friction 
against the air they are raised to incandescence and caused 
to emit light and heat. At certain seasons of the year 
they shower down upon us in great numbers. In Boston 
240,000 of them were observed in nine hours. There is 
no reason to suppose that the planetary system is limited 
to " vast masses of enormous weight;" there is, on the con- 
trary, reason to believe that space is stocked with smaller 
masses, which obey the same laws as the larger ones. That 
lenticular envelope which surrounds the sun, and which is 
known to astronomers as the Zodiacal light, is probably a 
crowd of meteors; and moving as they do in a resisting 
medium, they must continually approach the sun. Falling 
into it, they would produce enormous heat, and this 
would constitute a source from which the annual 
loss of heat might be made good. The sun, according 
to this hypothesis, would continually grow larger; but 
how much larger? Were our moon to fall into the 
sun, it would develop an amount of heat sufficient to 
cover one or two years' loss; and were our earth to 
fall into the sun a century's loss would be made good. 
Still, our moon and our earth, if distributed over the sur- 
face of the sun, would utterly vanish from perception. 
Indeed, the quantity of matter competent to produce the 
required effect, would, during the range of history, cause 
no appreciable augmentation in the sun's magnitude. The 
augmentation of the sun's attractive force would be more 
sensible. However this hypothesis may fare as a repre- 
sentant of what is going on in nature, it certainly shows 
