108 J. N. Lockyer on the supposed Compound 
very faintly visible, while dimmer still are seen the lines of the 
triplet between H and A. 
here is another series of facts in another line of work. In 
solar storms, as is well known, the iron lines sometimes make 
records his observation of the chromospheric lines, made on 
behalf of the United States Government, at Shumar, in the 
ow two very faint and short lines close to the triplet near 
G were observed to be injected thirty times, while one of the 
lines of the triplet was only injected twice. 
€ question next arises, are the triplets produced by one 
molecular grouping or by two? This question I also think 
the facts help us to answer. I will first state by way of re 
minder that in the spark photograph the more refrangible tnp- 
let is barely visible, while the one near G is very strong. Now 
if one molecular grouping alone were in question this relative 
intensity would always be preserved however much the abso- 
lute intensity of the compound system might vary, but if it 1s 
a question of two molecules we might expect that in some of 
the regions open to our observation we should get evidence of 
cases in which the relative intensity is reserved or the two 
intensities are assimilated. What might happen does happet: 
the relative intensity of the two triplets in the spark photograph 
is grandly reversed in the spectrum of the sun. The lines 
barely visible in the spark photograph are among the mo: 
prominent in the solar spectrum, while the triplet which 18 
strong in that photograph is represented by Fraunhofer lines 
not half so thick. Indeed, while the hypothesis that the 10? 
lines in the region I have indicated are produced by the vibra- 
tion of one molecule does not include all the facts, the hyp 
thesis that the vibrations are produced by at least three distinct 
molecules includes all the phenomena in a most satisfactory 
manner. 
