294 77 * $ Chemistry of the Future. [July, 
among the lowest of the metallic elements. We do not, 
therefore, see any reason why the above nineteen elements, 
if present in the sun, should elude our researches. 
The third hypothesis seeks to account for the absence of 
certain terrestrial elements in the solar atmosphere by as- 
suming that at the temperature there existing such elements 
would be dissociated, or rather that they could never be 
formed. This supposition may be tested by the following 
methods : — 
a. Physicists conclude that all the fixed stars are by no 
means equal in the energy of the thermic phenomena which 
they display. Some emit a pure and intense white light, 
and seem to be hotter than our sun ; others, of a deep yellow 
or red hue, are supposed to be in a more advanced stage of 
their career, and to have greatly cooled down. If this third 
hypothesis is correct the white stars will contain none of 
the elements absent in our sun, whilst some of those distin- 
guished in him will in them probably be missing. With 
the redder — or, generally speaking, the moye highly-coloured 
■ — stars, on the contrary, some of the elements absent in our 
sun ought to be recognised, and none which are found in 
him ought to be wanting. There is also, as we have already 
hinted, a further consideration : if any of our elements can- 
not exist in the sun or in the stars, it becomes highly probable 
that in the solar and stellar speCtra there will be indications 
of bodies, not existing as such , on our globe, but which are 
the materials from which such missing elements are com- 
posed. Mr. Lockyer, to whose researches in this direction 
we shall shortly refer, considers that a series of photographs 
of stellar speCtra will afford valuable information in regard 
to the constitution of certain substances now regarded as 
elementary. We may here remark that the discovery, in 
the sun or in the stars, of any element not found in the 
earth, is, with the means at our disposal, scarcely conceiv- 
able. The spectroscope shows us certain lines : some of 
these we identify with the characteristic lines of terrestrial 
elements ; others we fail to identify, and therein we reach, 
for the present, our limits. How can we, from out of the 
mass of unidentified lines, seleCt one as characteristic of x, 
another as belonging to y, and a third as peculiar to when 
these bodies are strictly, to us, unknown quantities ? 
b. The next method for the verification of the above hy- 
pothesis is a direCt attack of some of the supposed elements 
• — perhaps preferably some of the nineteen found wanting in 
the sun — from the most promising point of view. There 
may, perhaps, be little hope that any of our present simple 
