896 FRAGMENTS OF SCIENCE 



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 

 planetary bodies, drawn by the earth's attraction. They 

 enter our atmosphere with planetary velocity, and by fric- 

 tion 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 contrary, 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 Zodi- 

 acal 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 suffi- 

 cient 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 



