54 THE POPULAR SCIENCE MONTHLY. 



bits in which their components move, will for a moment adopt the 

 belief that they have been ejected from the stars, even though he may 

 accept the colorless theory (which explains nothing) that they were 

 captured by the giant planets from out the star-depths. 



Nor are we at all helped by remembering that the sun himself is a 

 star, and that certain among the meteors which reach the earth may 

 be supposed to have come from him. For assuredly the meteors re- 

 garded by Meunier and Tschermak as of terrestrial origin can not be 

 attributed to the sun as their source, while the orbits of all the recog- 

 nized meteor-streams are entirely inconsistent with such an origin. 

 Mr. Matthew Williams, in his "Fuel of the Sun," has pictured bodies 

 ejected from the sun which somehow come to be traveling afterward in 

 orbits nowhere approaching within millions of miles of his surface ; 

 but no such processes are within the range of dynamical possibilities. 



How, then, are we to retain at the same time what we regard as 

 proved by Daubree, and also those facts, inconsistent with Daubree's 

 theory as actually presented, which have been shown with equal cer- 

 tainty, either in their positive aspect (as in the case of the November 

 and August meteor-streams) or negatively, to be certainly inconsist- 

 ent with the supposed origin of meteorites from the stars ? Clearly 

 we must widen our range of survey so as to recognize an origin for 

 meteors and meteorites which, while including Daubree's facts, shall 

 not exclude the others ; and I think there can be very little doubt how 

 such widening of the range of survey should be effected. Widening 

 our survey of space will be of no service, for we only bring in more 

 distant regions, and the meteors we have to explain require a nearer 

 origin ; but if we widen our survey of time, as assuredly we are justi- 

 fied in doing (for many meteorites must be millions, nay, tens, hundreds 

 of millions of years old), we shall find other stars than those consid- 

 ered in Daubree's theory, and some of these may meet our difficulty. 



If there is one fact about the past of our earth and the other mem- 

 bers of the solar system which may be regarded as certain (amid all our 

 uncertainties in regard to the possible nebular origin of the system, or 

 its possible origin by aggregation, or by a combination of both pro- 

 cesses), it is that each planet began its career in a state of intense heat. 

 I suppose no one doubts now that the giant planets retain much more of 

 their primeval heat than the earth or Venus or Mars ; nor, on the other 

 hand, can it be reasonably doubted that the moon has parted with 

 much more of her original heat than our earth, insomuch that, whereas, 

 once she was the scene of such activities as we recognize in our world, 

 she is now a cold and lifeless orb. It is in their aspect as records of 

 the past of the planets that I note these facts. They indicate a pro- 

 gressive loss of heat w r hich we only have to trace back to recognize 

 each one of the planets, in the earliest stages of its career, as a sun- 

 like body. 



Extending, then, thus our survey in time, we find another set of 



