oe ee 
‘ 
Chemistry and Physics. 419 
° 
and strontium are all present together, the characteristic reactions of the 
alkalies appear first; those of calcium and strontium usually somewhat 
later. When these last are present only in very minute quantities, their 
spectral reactions do not appear; we obtain them however, immediately 
when the wire is moistened with muriatic acid, and held for a few mo- 
ments in the reducing flame. 
e authors point out the importance of these simple processes in a geo- 
logical and minerological point of view. Thus sea-water is easily shown 
to contain potassium, lithium, calcium, and strontium, and many other 
very interesting and important examples are given, 
Sarium.—tThe spectrum of Barium is the most cneieliiated of all those 
_ yet investigated. It contains two bright green lines between the spectral 
lines E and F but nearer to E; these the authors denote by Bae and 
Ba@. A third line Bay is less sensitive, but still characteristic. The 
spectral reaction of the barium compounds is somewhat less sensitive than 
d: about +,Ayo of a milligramme of 
barium is exhibited with perfect distinctness. The cehlorid, bromid, iodid, 
end ofthe spectrum and compares in intensity and distinctness with the 
lithium line. et lowe: 
The spectral analysis promises to furnish also a method of investigating 
the chemical nature of the atmospheres of the sun and of the brighter 
- fixed stars 
i ; theoretical considerations, that the spectrum 
et ee abet uree of light of sufficient intensity 
ino a continuous spectrum, 1s placed behind it. In other — 
the bright lines are under these circumstances converted into dark ones. 
direct experiment the above conclu- 
icht lines of potassium, sodium, lithium, 
