590 



NATURE 



[April 19, 1888 



But even in the nucleus of a comet as in a star it is 

 niucli more easy to be certain of the existence of bright 

 lines than to record their exact positions/ and as a matter 

 oif JFact bright lines have been recorded, notably in Comet 

 Wells and in the great comet of 1882. 



The main conclusion to which my researches have led 

 me is that the stars now under consideration are almost 

 identical in constitution with comets between that con- 

 dition in which, as in those of 1866 and 1867, they give 

 VIS the absolute spectrum of a nebula and that put on by 

 the great comet of 1882. 



I am aware that this conclusion is a startling one, but a 

 little consideration will show its high probability, and a 

 summary of all the facts proves it, I think, beyond all 

 question. 



While we have bright lines in comets, it can be 

 shown that some of them are the remnants of flutings. 

 Thus in Comet III. of 1881, as the carbon lines died 

 away the chief manganese fluting at 558 became con- 

 spicuously visible ; it had really been recorded before 

 then. The individual observations are being mapped in 

 order that the exact facts may be shown. It may 

 probably be asked how it happened that the fluting of 

 magnesium at 500 was not also visible. Its absence, 

 however, can be accounted for : it was masked by the 

 brightest carbon fluting at 517, whereas the carbon 

 fluting which under other circumstances might mask the 

 manganese fluting at 558 is always among the last to 

 appear very bright and the first to disappear. 



In the great comet of i832, which was most carefully 

 mapped by Copeland, very many lines were seen, and 

 indeed many were recorded, and it looks as if a complete 

 study of this map will put us in possession of many of 

 the lines recorded by Sherman in the spectrum of y 

 Cassiopeiae. We have then three marked species of non- 

 revolving swarms going on all fours with three marked 

 species of revolving ones, and in this we have an ad- 

 ditional argument for the fact that the absence in the 

 former of certain flutings which we should expect to 

 find may have their absence attributed to masking by 

 the carbon flutings. 



We have next, then, to show that there are carbon 

 bands in the bright-line stars. 



There is evidence of this. Among the bright lines 

 recorded is the brightest carbon fluting at 517. This is 

 associated with those lines of magnesium and manganese 

 aad iron visible at a low temperature which have been 

 seen in comets. 



But we have still more evidence of the existence of 

 carbon. In a whole group of bright-line stars there is a 

 bright band recorded at about 470, while, less refrangible 

 than it, there appears a broad absorption band. I regard it 

 as extremely probable that we have here the bright carbon 

 band 467-474, and that the appearance of an absorption 

 band is due to the fact that the continuous spectrum of 

 the meteorites extends only a short distance into the blue. 



If we consider such a body as Wells's comet, or the 

 great comet of 1882, as so great a distance from us that 

 only an integrated spectrum would reach us, in these 

 cases the spectrum would appear to extend very far, and 

 more or lesscontinuously, into the blue ; but this appear- 

 ance would be brought about, not by the continuous 

 spectra of the meteorites themselves, but by the addition of 

 the hydrocarbon fluting at 431 to the other hot and cold 

 carbon bands in that part of the spectrum. 



There are other grounds which may be brought forward 

 to demonstrate that the difference between comets and 

 the stars now under discussion is more instrumental than 

 physical. 



Supposing that the cometic nature of these bodies be 



^ " Observations of Comet III., 1881, June 25.— The spectrum of the 

 nucleus is continuous ; that of the coma shows the usual bands. With a 

 larrpw ijit there are indications of many lines just beyond the verge of dis- 

 tinct' visibility." — Copeland, Copernicus, vol. ii. p. 226. 



conceded, the laboratory work will show us which flutings 

 aijd lines will be added to the nebula spectrum upon each 

 rise of temperature ; and the discussion, so far as it has 

 gone, seems to show that such lines and flutings have 

 actually been observed. 



The difficulties of the stellar observations must always 

 be borne in mind. It will also be abundantly clear that 

 a bright fluting added to a continuous spectrum may 

 produce the idea of a bright line at the sharpest edge 

 to one observer, while to another the same edge will 

 appear to be preceded by an absorption band. 



III. Stars with Bright Flutings accompanied by 

 Dark Flutings. 



I also showed in the paper to which reference has 

 been made that the so-called "stars" of Class \\\,a 

 of Vogel's classification are not masses of vapour like our 

 sun, but really swarms of meteorites ; the spectrum being 

 a compound one, due to the radiation of vapour in the 

 interspaces and the absorption of the light of the red- 

 or white-hot meteorites by vapours volatilized out of them 

 by the heat produced by collisions. The radiation is that 

 of carbon vapour, and some of the absorption, I stated, 

 was produced by the chief flutings of manganese. 



These conclusions were arrived at by comparing the 

 wave-lengths of the details of spectra recorded in my 

 former paper with those of the bands given by Duner in 

 his admirable observations on these bodies.^ 



The discovery of the cometic nature of the bright-line 

 stars greatly strengthens the view I then put forward, not 

 only with regard to the presence of the bright flutings of 

 carbon, but with regard to the actual chemical substances 

 driven into vapour. From the planetary nebulae there is 

 an undoubted orderly sequence of phenomena through 

 the bright-line stars to those now under consideration, 

 if successive stages of condensation are conceded. 



I shall return to these bodies at a later part of this 

 memoir. 



IV. Stars in which Absorption Phenomena 

 predominate. 



I do not suppose that there will be any difficulty in 

 recognizing, that if the nebula;, stars with bright lines, 

 and stars of the present Class \\\.a are constituted as I 

 state them, all the bodies more closely resembling the sun 

 in structure, as well as those more cooled down, must 

 find places on a temperature curve pretty much as I have 

 placed them ; the origin of these groups being, first still 

 further condensation, then the condition of maximum 

 temperature, and then the formation of a photosphere 

 and crust. 



We shall be in a better position to discuss these later 

 stages when the classifications hitherto adopted have been 

 considered. 



{To be continued.) 



THE HfTTITES, WITH SPECIAL REFERENCE 

 TO VER V RECENT DISCO VERIESr 



IV. 



THOSE who have attempted to decipher the Hittite 

 inscriptions have not always regarded a fact which 

 may be discerned with tolerable facility. The inscrip- 

 tions from Hamath, and those from Jerablus or Car- 

 chemish, though no doubt deriving their origin from a 

 common source, yet present, as we know them, two dis- 

 tinct types. Symbols usual and frequently repeated on 

 the Jerablus monuments are wholly absent from those of 



'■ "Les Etoiles a spectres de la troisieme classe,"^A'(?«^/. Svenska Vitens- 

 kaps-Akadetniens Handlingar, Bandei 21, No. 2, 1885. 



^ Based on Lectures delivered by Mr. Thomas Tyler at the British Museum 

 in January 188 3. Continued from p. 562. 



