beatae Poni ti ale 
ae 
Nature of the so-called Elements. 109 
Lithium. ve 
Before the maps of the long and short lines of some of the 
chemical elements compared with the solar spectra, which were 
published in the Phil. Trans. for 1878, “ Plate IX,” were com- 
municated to the Society, I very carefully tested the work of 
prior observers on the non-coincidence of the red and orange 
lines of that metal with the Fraunhofer lines, and found that 
neither of them were strongly if at all represented in the sun, 
and this remark also applies to a line in the blue at wave- 
length 4603. 
The photographic lithium line, however, in the violet, has a 
strong representative among the Fraunhofer lines. 
Applying, therefore, the previous method of stating the facts, 
the presence of this line in the sun differentiates it from all the 
others. For the differentiation of the red and yellow lines I 
need only refer to Bunsen’s spectral analytical researches, which 
were translated in the Philosophical Magazine, December, 1875. 
In Plate IV, two spectra of the lithium chloride are given, 
one of them showing the red’ line strong and the yellow one 
feeble, the other showing merely a trace of the red line, while 
the intensity of the yellow one is much increased, and a line 
in the blue is indicated. Another notice of the blue line of 
lithium occurs in a discourse by Professor Tyndall, reprinted 
in the Chemical News, and a letter of Dr. Frankland’s to 
Philosophical Magazine, vol. xxii, p. — 
“On throwing the spectrum of lithium on the screen yore, 
hence does this blue line arise? Does it really belong to 
the lithium, or are the cone points or ignited air guilty of its 
production? I find there blue bands with common salt, but 
they have neither the definiteness nor the brilliancy of the 
lithium band. When lithium wire burns in air it emits a 
somewhat crimson light; plunge it into oxygen, and the light 
changes to bluish white. This seems to indicate that a high 
temperature is necessary to bring out the blue ray.” 
Postscript, Nov. 22, 1861.—I have just made some further 
experiments on the lithium spectrum, and they conclusively 
prove that the appearance of the blue line depends entirely on 
the temperature. The spectrum of lithium chloride, ignited in 
a Bunsen’s burner flame, does not disclose the faintest trace of 
Am. Joor. Beige Series, Vou. XVII, No. 98.—Fes., 1879. 
