40 C. PIAZZt SMYTH ON THE 



spectroscope I had ever used ; and on bringing in our old friends of the little b 

 group, there was not only all that Dr Schellen and Professor Vogel have 

 recorded for the latter— not only too all the physical features which I had noted 

 with difficulty at Madeira, — but there were b z and b i , each of them as clearly 

 doubled, and their components clean separated, as any observer could possibly 

 desire. Of b z one line was shown to be much stronger than the other, but 

 equally sharp ; while of b A one line, the stronger also of the pair, was evidently 

 hazy, and just as accurately concentric with that cloud of haze, as were the 

 old b 1 and 6 2 with regard to their clouds of haze ; but the new and weaker 

 component of 6 4 was evidently excentric to the haze of 6 4 ; a further test now 

 of performance, but whose additional utility will presently appear. 



So far then as mere optical definition was concerned, nothing could be more 

 satisfactory, or rather I should say transcendent, than this trial of the new 

 College spectroscope on the little b group ; though it had been preceded in its 

 detection of duplicities merely, by the American observers, and also by M. 

 Thollon in France, and M. Fievez in Belgium. But those gentlemen have 

 not, so far as I know, taken the further step of investigating chemically and 

 physically the ultra nice points of optical discovery which they have added to 

 the b group. 



I do not of course by this allude to what every one may read in Angstrom's 

 admirable normal map, as to b 1 , b 2 and & 4 , all of them now known to be endued 

 with a remarkable haze, being the reversals of magnesium metal burning in the 

 Sun, and 6 3 , so strikingly without haze, being a similar representative of iron ; 

 — but to this further detail, that under and coincidently with 6 4 , Angstrom 

 placed an iron, as well as a magnesium line ; and under b 3 , a nickel, as well as 

 an iron line. Or, as his followers are delighted to assert, 6 3 and b A are basic 

 lines ; viz., one line standing as a base for two metals. The principle therefore 

 of any such basic line represents a new chemistry, where two earthly elements 

 are, by long roasting in Solar heat, resolved into one element, forming a 

 common base to them both. So that certain reputed simple and original 

 elements of the chemists hitherto, are really compound bodies ; and the list of 

 elements in the Sun, is shorter than that which is accepted on the earth. 



It is something of a check to that system, to he enabled to say from mere 

 optical observation, that in the two instances in little b, where basic lines had 

 been thought to be met with, superior spectroscopes have shown there are two 

 lines in each case ; but much more than that is necessary for full proof ; for 

 who can be certain that any two given spectrum lines seen very close together, 

 in place of representing a mere chance, or optical, coincidence of two perfectly 

 unconnected elements' lines, may not be a physically double line of some one 

 metal. 



I have therefore been trying the Cooke Spectroscope on this point, by 



