On the Chemistry of the Hottest Star, 



197 



Professors Eder and Valenta thus state the conclusions they have 

 recently arrived at in their study of the changes in the spectrum of 

 mercury : — 



" Ferner ist die Brscheinung des ziemlich unvermittelten Auf- 

 blitzens des Hnien-reichsten Spectrums (siehe die Abbildung, fig. 8, 

 der heliographirten Tafel) bei hochgradig gesteigerter Starke des 

 Flaschenfunkens und gleichzeitigera Erhitzen der Capillare, beson- 

 ders das Auftauchen zahlreicher neuer Hauptlinien, welche friiher 

 nicht oder kaum sichtbar waren, und mancher Doppellinien an Stelle 

 von einfachen Linien, eine derartige, dass sie zu Lockyer's Theorie 

 der Dissociation der Elemente passen wiirde, wenn man iiberhaupt 

 die Zerlegbarkeit unserer Elemente in die Discussion ziehen will."* 



[Translation : — 



" Moreover the appearance of the great brilliancy of the richly 

 lined spectrum with a high tension jar spark, the capillary being 

 heated, and especially the interchange of a great number of new 

 lines which were dim before, and also the change of single lines into 

 double ones ; these are such that would harmonise well with 

 Lockyer's theory of dissociation of the elements, if one is prepared 

 to bring into the discussion the possibility of the dissociation of the 

 chemical elements."] 



I am glad to be able to quote the following opinion of Mr. Crookes,t 

 to which I attach great weight : — 



" Until some fact is shown to be unreconcilable with Mr. Lockyer's 

 views, we consider ourselves perfectly justified in giving them our 



of Class IITa (Group II) is something like that of the electric arc, while that of 

 the stars of Class Ila is higher, and that of stars of Class la is at least as high as 

 the temperature of the high-tension spark from a Leyden jar. This view receives 

 striking confirmation in the precisely opposite behaviour of the magnesium line at 

 X 4352-18. First becoming visible in the spectra of type la (Group IV), which 

 have numerous lines, it is strong in the spectra of type Ila (Groups III and V), 

 and increases so as to be one of the strongest lines as we pass towards type Ilia 

 (Group II). Now, as was found by Liveing and Dewar, this line exhibits just the 

 same peculiarities in the laboratory ; in the spark spectrum it is hardly recognis- 

 able, in 1he arc spectrum it is very strong." 



The association of 4352 with 4481 in the hottest stars, if the stellar line really 

 coincides with the magnesium line 4352, suggests that this is perhaps the last 

 surviving line of the lower temperature spectrum wken a very high temperature is 

 reached, but there is nothing in the appearance of this line in the spark spectrum 

 with large jars which would lead us to expect a behaviour similar to that of 4481. 

 It is not impossible, then, that the faint line near 4352 in the hottest stars is not a 

 magnesium line at all. 



# ' Denkschriften der kaiserlichen Akademie der Wissenschaften,' Wien, Bd. 61 

 p. 429, 1894. 



f ■ Chem. News,' 1879, vol. 39, p. 65. 



p 2 



