802 Mr. W. Crookes on the existence of a new Element, 
strongly-marked line which might lead to the identification of 
either of these elements, it was not until I had in vain tried 
numerous chemical methods for isolating the tellurium which I 
supposed to be present, that the method of spectrum-analysis was 
used. A portion of the residue, introduced into a blue gas-flame, 
gave abundant evidence of selenium ; but as the alternate light 
and dark bands due to this element became fainter, and I was 
expecting the appearance of the somewhat similar, but closer, 
bands of tellurium, suddenly a bright green line flashed into view 
and as quickly disappeared. An isolated green line in this por- 
tion of the spectrum was new to me. I had become intimately 
acquainted with the appearances of most of the artificial spectra 
during many years’ investigation, and had never before met with 
a similar line to this; and as from the chemical processes through 
which this residue had passed the elements which could possibly 
be present were limited to a few, it became of interest to discover 
which of them occasioned this green line. 
After numerous experiments, I have been led to the conclu- 
sion that it is caused by the presence of a new element belong- 
ing 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 very positively. I am, how- 
ever, 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 account 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 introduced into the burner 
of the spectrum apparatus giving rise to a brilliant green Ime, 
perfectly sharp and well-defined upon a black ground, and 
almost rivalling the Na line in brilliancy. It is not, however, — 
very lasting: owing to its volatility, which is almost as great as 
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 imtroduced into the flame gradually, the 
line continues present for a much longer time. 
The properties of the substance, both in solution and in the 
dry state, as nearly as I can make out from the small quantity 
at my disposal, are as follows :— 
1. It is completely volatile below a red heat, both in the 
elementary state and in combination (except when united with 
a heavy fixed metal). 2. From its hydrochloric solution it is 
readily precipitated by metallic zinc in the form of a heavy black 
powder, insoluble in the acid liquid. 38. Ammonia added very 
gradually until in slight excess to its acid solution, gives no pre- 
cipitate or coloration whatever, neither does the addition of car- 
