382 CELESTIAL CHEMISTRY. 



devolution : but does the one process compensate for the other? 

 Is the cosmos a closed curve endlessly repeating itself? Or is 

 it an open curve, tending we know not w^iither ? — a clock once 

 wound up and now running down ? Here science gets out of 

 its depth, but this much it can testify to. Stars are growing 

 hotter, and stars are cooling : here the elements, as we know 

 them, are being built up, there they are being broken down. 

 Beyond that science ceases and speculation begins. And 

 admitting that a nebula is the first stage in the development 

 of a solar system, even then, as Sir George Darwin said at 

 Johannesburg, " Such primitive nebulae stand in as much need 

 of explanation as their stellar offspring " and " the advance 

 towards an explanation of the universe remains miserably 

 slight." 



Some may think that I have not fulfilled my title ; that there 

 has not been enough of chemistry in my remarks : but that 

 can only be because of the other sciences inextricably inter- 

 twined with it. Did I not say truly that the spectroscope 

 symbolised the meeting of the sciences ? Beneath the limitless 

 celestial dome all the sciences — all the forces of Nature — work 

 in harmony. The vault of the heavens covers a boundless 

 chemical laboratory, and the stars — as Sir David Gill has 

 phrased it — are the crucibles of the Creator; the incandescent 

 bottles which Sir Norman Lockyer once longed for that he 

 might examine at leisure the chemical changes produced at the 

 high temperature of the centre of the fleeting electric spark. 

 The spectroscope enables us to peer into those crucibles, if 

 perchance we may descry something of the wonderful reactions 

 that take place there. By means of this exquisitely delicate 

 instrument, well said to be — next to the balance — the most 

 useful and important appliance which the chemist possesses, 

 the whole science of celestial chemistry has been built up from 

 its very foundations in less than the last half century. We know 

 more to-day about the chemical conditions of immeasureably 

 distant stars than we could have hoped, fifty years ago, ever to 

 know about our own sun. The spectroscope, by affording an 

 insight into the conditions of hotter and cooler stars, gave us 

 the first inkling of the possibility of splitting" up the elements, 

 as we call them, into less complex substances; and what Sir 

 William Ramsay appears to have only just succeeded in proving 

 experimentally in regard to radium and helium, was inferred 

 by Sir Norman Lockyer, from his spectroscopic observations 

 of the stars, more than a quarter of a century ago. 



The spectroscope has also more clearly demonstrated that 

 there is no stagnation in nature, but that vast chemical changes 

 are ever in progress, and that there is an unending and 

 stupendous activity in the heavens. The seeming fixity of the 

 fixed stars is an illusion, for the spectroscope in the hands of 

 Sir William Huggins has been largely instrumental in proving, 

 by a method which I have no time to enter into more fully. — I 

 hinted at it earlier in this paper— that individual stars are rushing 

 hither and thither at immense speeds, in fact, that whole star 

 systems are streaming onwards through space — like stupendous 

 cosmic rivers whose drops are suns — with incredible swiftness : 



