THE NEBULAR HYPOTHESIS 225 



of science was there heard against it. At that time it was 

 regarded as ' ' one of the most well-attested facts of hu- 

 man knowledge ' '. Now, if there was anything clear about 

 that conception, it was, that absolutely the whole of the 

 matter that composed the Neptunian annulus went into 

 that planet and his satellites ; so in the case of the Urani- 

 an annulus, and so in turn with all the planetary annuli 

 down to and including Mercury's. Yet in all the esti- 

 mates I have come across in my reading, I have failed to 

 find a single one that does not construe the Helmholtzian 

 sun as having contracted from the very periphery of the 

 original nebula. What is the meaning of such crass mis- 

 representation! Is it due to innocent oversight, or to 

 stupidity, or to intentional duplicity? Be the reason 

 what it may, the truth remains that the sun cannot be 

 consistently predicated as having collapsed upon itself 

 from a greater distance than from the line of Mercury's 

 orbit. Now, Mercury is only 1-80 as far from the sun's 

 center as Neptune, and if we take the square root of 80 

 (to allow for gravitational variation) and divide Young's 

 estimate by that quantity, the life of the sun becomes 

 theoretically reduced to a paltry 2,000,000 years ! 



The situation is in no way improved by postulating a 

 meteoric in lieu of a gaseous nebula, should such a sub- 

 stitution be attempted. In the contemplation of science 

 the original nebula, however constituted, possessed a con- 

 certed movement of rotation about an axis, and there is 

 no logical warrant for asserting that part of it took on 

 orbital motion while the rest was free to fall. Even con- 

 ceding that this last may have been the case, that part 

 which was free to fall would inevitably have traversed 

 the distance from Neptune to the sun within a few years 

 at most, and its collisional effects been ages ago dis- 

 sipated. Indeed, it was precisely to escape this galloping 

 culmination that caused astronomers to look with so much 

 more favor on the gaseous hypothesis. In all cosmologi- 

 cal speculations, duration is of the essence, and particu- 

 larly is this the case here. So far, then, as the Helm- 

 holtzian explanation of the solar heat is concerned, the 



