SOLAE CHEMISTKY. 
209 
others following him, thought that the Light emitted from the 
photosphere was, from the first, deficient in those rays, or that 
they were lost, either by absorption in passing through the 
solar atmosphere, or possibly in passing through that of the 
Earth. Angstrom, — who also discovered many bright lines in 
the spectra from artificial lights,— advanced some highly philoso- 
phical views in 1855; but the investigations of Bunsen and 
Kirchoff, remarkable alike for the delicacy and caution observed 
in the inquiry, and for the refined nature of them deductions, 
lead us probably up to the true explanation of these phenomena. 
The dark hues of the Solar Spectrum, and the bright ones 
observable in the spectra obtained from artificial lights, have 
been investigated by Professor Wheatstone, Dr. W. A. Miller, 
Air. Fox Talbot, and Sir John Kerschel. These investigators 
have proved that the spectra obtained from the Light emitted 
from incandescent mineral bodies differ from that obtained 
from the Sun ; that the lines from artificial sources of Light 
are, in many cases, peculiar ; and that, in the majority of 
instances, bright lines appear to take their place. So rigidly 
exact were the positions and characters of the lines obtained 
from differently coloured flames, that both Wheatstone and 
Miller suggested the adoption of spectral or prismatic analysis, 
as a means of determining the presence of exceedingly minute 
quantities of any substance. The investigations of Bunsen and 
Kirchoff have, from their high interest, again drawn attention 
to this subject. These hues, dark and bright, have been 
employed in the analysis of the solid mass of the Sun itself ; 
and the extreme delicacy of the indications is proved from the 
discovery, by Bunsen, of two new metallic bodies — one called 
caesium (meaning bluish gray), and the other rubidium (from 
the Latin rubidus, which was used to express the darkest red- 
colour), which existed in infinitesimally small quantities in some 
mineral waters of Germany. 
By the beauty of the new phenomena observed, and by the 
boldness of the deductions drawn from the experiments made, 
the greatest additional interest has been added to this class of 
investigations. The discoveries, it must not be forgotten, have 
been arrived at by a series of steps, every one of them of the 
utmost importance, and it cannot but be regretted, that the 
most recent investigators have exhibited a singular blindness to 
the labours of other men. In the history of science, this will 
not redound to the honour of those in every way eminent philo- 
sophers, who unfortunately have not been able to rise above 
the little jealousies of ordinary mortals. 
To render the phenomena, and the hypothesis involved, intel- 
ligible to those who may not have studied the subject, it is 
necessary to recapitulate, and enter a little into detail. 
