588 
EDITORIAL OBSERVATIONS. 
to few, it became of interest to discover which of them 
occasioned this green line. After numerous experiments, I 
have been led to the conclusion that it is caused by the 
presence of a new element belonging to the sulphur group; 
but, unfortunately, the quantity of material upon which I 
have been able to experiment has been so small that I 
hesitate to assert this positively. I am, however, at work 
upon some of the seleniferous deposit itself, and hope 
shortly to be able to speak more confidently upon this point, 
as well as to give some of its properties. 
“ In the purest state that I have as yet succeeded in 
obtaining this substance it communicates as definite a 
reaction to the flame as soda, the smallest trace intro¬ 
duced into the burner of the spectrum apparatus giving rise 
to a brilliant-green line, perfectly sharp and well-defined, 
upon a black ground, and almost rivalling the old line in 
brilliancy. It is not, however, very lasting, owing to its 
volatility, which is almost as great as that of selenium. A 
portion introduced at once into a flame merely shows the 
line as a brilliant flash, remaining only a fraction of a 
second; but if it be introduced into the flame gradually, the 
line continues present for a much longer time.” 
A number of experiments were instituted by Mr. Crookes 
to ascertain if, by possibility, any other element might have 
been mistaken for it; but he asserts that the reactions 
which took place were decided ; and to remove any remaining 
doubt he specially examined the spectra produced by each 
element in detail, either in its elementary state or most 
important compounds. Many of them gave rise to spectra 
of great and characteristic beauty, but none gave anything 
like the green line, nor, in fact, is there any artificial 
spectrum, except that of sodium, -which equals it in 
simplicity. 
He goes on to say, “ There still may be urged the pos¬ 
sibility of its being a compound of two or more known 
elements, or an allotropic condition of one of them; a 
moment's thought will, however, show that neither of these 
hypotheses is tenable. They would, in reality, prove what 
they are raised to oppose, for nothing less could follow than 
