256 



KNOWLEDGE & SCIENTIFIC NEWS. 



[Nov., 1904. 



Modern Cosmogonies. 



l:!y Miss Agnes Ci.erke. 



XI. — The Procession of the Survs. 



I'FiiiNfiMENA are fum-lions of lime ; .Tiid the form of 

 the funrtion has to Ijo clcterniincd in each partieuhir 

 case. That is what the liistorical method ct)mes to ; 

 .ind its use is prevalent and almost compulsory. \\'e 

 can no Ioniser be satisfied with ;i simple bird's-eye view 

 of the iinixerse ; our thoughts are irresistibly driven to 

 grope into its past, and to divine its future. Static 

 conceptions sulliced for our intellectual forefathers. 

 Thev aimed at establishing the equilibrium of things, 

 while we see them in a never-ending" flux. One .aspect 

 of them calls up the next, and that .another, and so on 

 <id infinHiiiii ; we cannot, if we would, balance our 

 ideas on the pivot of the transient present. 



'Ihe immutable heavens of the ancients strike us to- 

 da\ as the inxention of a strange r.ace of beings. We, 

 on the contrary, see them with .Shelley as a " frail and 

 fading sphere" — a "brief expanse," the seat and 

 scene of change. The " fixed " stars long ago broke 

 ;iwav from their nifiorings, and began to flit at large 

 llirongh sp.ace. Of late, a less obxious, more intimate 

 kiiul ol mobilifv has been attrilnited to them. (iroo\es 

 ot indi\idu.il dc\ el(i|iment seei'n prepared for them, 

 along which thev shilt as the tardy ages go bv ; and 

 since e\erylhing that grows must decay, the orbs cf 

 heaven, too, incur the doom of mortality. Modern 

 science, howe\er, has done much more than extend to 

 them the dismal philosophy of the phrase, " ioiii passe, 

 ii)!(t cassc, ioiif hissc." The grandiose enterprise has 

 been not unsuccessfully essayed of tracing in detail tile 

 progress of sidereal evolution, and of marshalling the 

 vast stellar battalions in order of seniority. This has 

 been rendered feasible by the disclosures of the spectro- 

 scope. Apart from their guidance, the tr.ack might 

 have been glimpsed here and there, but could never 

 have been laid down with any approach to definiteness. 

 Herschel found for it a icrm'tmis h quo In nebulae of 

 various forms, but attempted to pursue it no further. 

 We do not hesitate to run it on, from station to station, 

 right down to the Icnniiuis ad qiicm — not, indeed, with- 

 out the perception of outstanding difTiculties and in- 

 securities. They appear, howe\'er, to be outweighed 

 by a certain inevitableness of self-arrangement in the 

 visible facts. 



The argument from continuity is that mainly relied 

 upon. An unbroken succession of instances is strongly 

 persuasive of actual transition, pro\ided only that a 

 principle of de\elopment (so to call it) may reasonably 

 be assumed as influential. A series of mineralogical 

 specimens, however finely differenced, does not suggest 

 the progressive enrichment of one original mass of ore. 

 In the stars, on the other hand, a species of vitality may 

 be said to reside. They are not finished-ofT products', 

 fnit self-acting machines. They are centres of energy, 

 which they dispense gratis, supplying the cost out' of 

 their ()wn funds. And Ihe process is not only obviously 

 torminabli', hut must be accompanied by constitutional 

 alterations, which might be traceable by'subtle methods 

 of enquiry. They are traceable, unless we arc decei\ed 

 by illusory appearances. 



-Secchi's classification of the stars was unwarped bv 

 any speculative fancy. It was purely formal ; it aimed 



only at providing distinct compartments for the con- 

 venient arrangement of a multitude of differently 

 characterised items of information. Then by degrees, 

 the close gradation of one class into the next came to 

 be noticed; the partitions melted away; the methodised 

 array showed itself to be in movement ; and the bare 

 framework took shape, under the auspices of Z(')llner 

 and Vogel, as a cosmic pedigree. The white stars 

 were set forth as the progenitors of yellow, yellow of 

 red stars ; ;md the insensibly progressive reinforce- 

 ment of the traits of relationship between the successive 

 types went far towards demonstrating some partial, if 

 not a complete, correspondence of the indicated order 

 with the truth of things. It has since been found 

 necessary to divide the first stellar class into helium 

 and -Sirian stars ; and here, too, essential diversity 

 shades off imperceptibly into likeness approximating 

 to identity. All the groups hang together ; the entire 

 scheme is on an inclined plane of change. Helium 

 stars, as the^■ condense, pass into Sirian, these into 

 solar stars ; which finally, reddening through the in- 

 crease of absorption, exhibit the badge of post-meri- 

 dional existence in fluted spectra. The finality of the 

 red st.age is, indeed, very far from being absolute, but 

 what lies Ijeyond is matter of conjecture. 



There are se\eral good reasons for taking helium 

 stars to be the "youngest," or most primitive of the 

 amazing assemblage that sparkle in the vault o{ 

 he.aven. The first is their affinity with nebulae. Every 

 star, perceived to be involved in folds or effusions of 

 shining haze, has yielded — if liright enough for profit- 

 able examination — a spectrum of helium quality. 

 I'urther, they arc rcmark.ably tenuous bfidies. It has 

 been ascertained with some definiteness, from the in- 

 vestigation of stellar eclipses, that helium stars arc 

 commonly, perhaps invariably, of far slighter consist- 

 ence than the sun. Radiation, however, is maintained 

 bv contraction ; hence, orbs at the outset of their course 

 must be, f)n the whole, the most diffuse. A third note 

 of youth is membership of embryo systems ; and this is 

 affixed very markedly to helium stars. One-third, cer- 

 tainly, probably one-half of those lately submitted to 

 trial by Professors Frost and Adams proved to have 

 spectroscopic companions. They are pairs believed to 

 ha\e been recently (in the cosmic sense) divided bv 

 fission. And this is an operation which must, we 

 should suppose, be undergone early, or not at all. 



The spectra of helium stars are peculiar and sugges- 

 ti\'e. Thfise belonging to Miss Maury's earliest 

 groups — many of them visibly nebulous — bear next to 

 no traces of metallic absorption, showing instead lines 

 of oxygen, nitrogen, and of hydrogen in all its three 

 series. The conditions, accordingly, needed to produce 

 the " cosmic " modification of hydrogen arc realised in 

 these inchoate bodies. What those conditions actually 

 are, we cimnot tell ; vet it may be confidently surmised 

 that they will prove to be of an electrical nature. 

 Hydrogen resembles the metals in being electro-posi- 

 tive ; it collects at the negative pole during the electro- 

 lytic decomposition of water. There is, however, an 

 unmistakable tendency In primitive sidereal objects to 

 display absorption-rays of electro-negative rather than 

 of electro-positive elements. It is conceivable that hy- 

 drogen may be capable of altering its behaviour in 

 this respect; and that the molecules radiating the 

 Pickering and Rydberg series, in afldition to the more 

 familiar Huggins series, have, in fact, through some 

 corpuscular re-arrangement, assumed the electro-nega- 

 tive quality properly characterising a non-metallic 

 substance. The association of this form of hydrogen 



