170 Mr, J. N. Lockyeron Recent 



To this it may be replied that, although these red lines may 

 be apparently the brightest to the eye, it by no means follows 

 they are the longest, since they are situated in a part of the 

 spectrum which affects the visual organ more strongly than the 

 photographic region does. It is possible also that the reason- 

 ing I have lately used in a paper communicated to the Royal 

 Society, on the spectrum of calcium, may be applied in these 

 cases. 



Since a sensitized film is affected by some rays more strongly 

 than by others, in determining the lengths of lines from a pho- 

 tograph it is not fair to compare together portions of the 

 spectrum separated by too great an interval. 



Furthermore, the fact of these red lines having been over- 

 looked in the solar spectrum is not conclusive proof of their 

 absence, inasmuch as this portion of the spectrum is both 

 brighter and less refrangible, and a greater degree of disper- 

 sion would be necessary when prisms are employed to render 

 visible faint dark lines which are easily detected in the photo- 

 graphic region. 



At present, then, out of the fifty-one metals with which 

 we are acquainted here, more than thirty are known to exist 

 in the sun with more or less certitude. Now it was a very 

 remarkable thing that although such metalloids as carbon and 

 sulphur, iodine, bromine, and the like, had been very dili- 

 gently searched for, no trace whatever had been found of 

 them, giving any evidence that they existed together with the 

 metals in these zones (these shells) to which I have referred. 



Some years ago evidence was brought forward of the pos- 

 sible existence of the metalloids as a group outside the metals ; 

 and the evidence for this suggestion was of the following 

 nature: — Independently of any questions connected with solar 

 physics, I think all students of science now agree that the 

 vapours of the various elementary bodies exist in different 

 molecular states ; if these different molecular states are studied 

 by means of the spectroscope, perfectly different spectroscopic 

 phenomena present themselves. If we use a large coil, we 

 can drive every chemical substance with which we are 

 acquainted, including carbon and silicon, into a molecular 

 grouping competent to give us what is called a line spectrum, 

 the spectrum with which we are most familiar when we use 

 metals or salts of metals in the electric arc. 



If, however, other conditions are fulfilled ; if these bodies 

 are not so roughly handled — if, in other words, we employ a 

 lower degree of heat, or if we use electricity so that we get 

 quantity instead of tension, then these line spectra die away 

 altogether, and wo have a spectrum, so called, of channelled 



