THE ULTRA-VIOLET SPARK SPECTRA. 129 
salts, the lines of the metal do not appear in the case of borates, and only 
the strongest line of sodium (A=3301) can be observed in the spectrum 
of silicates, even when concentrated solutions are used. These are the first 
spectra of boron and silicon obtained from metallic salts. Their lines are 
the foilowing :— 
Boron. SILICON. 
Wave-lengths Wave-lengths 
3450°1 2881°0 
2497°0 2631°4 
2496-2 2541-0 
2528°1 
2523 5 
2518°5 
2515°5 
2513°7 
2506°3 
2435-5 
In Messrs. Liveing and Dewar’s map of the carbon spectrum,! and in 
the list of the carbon lines, and in the map of the iron spectrum,? a 
number of lines are given which are absent from the photographs of the 
spectrum of graphite published in the Transactions of the Royal Dublin 
and in the Journal of the Chemical Society. Many hundreds of spectra 
taken between graphite poles have failed to show a trace of these lines, 
and as the spectra have been photographed under varying conditions it is 
scarcely likely that the lines in question are really carbon lines. They 
have now been identified with the spectrum of silicon. The following 
are their wave-lengths :— 
LINEs FROM THE CARBON SPECTRA Smi1con 
(Liveing and Dewar) (Hartley) 
Spark Are Spark 
— F ‘ : 288k: : ¢ . 2881:0 
25410 . : ‘ — F 4 : . 2541:0 
25282. . : se AD2Selh : ‘ . 2628+1. 
2523°6 . ; f PBT ae & . 2523°5 
25187 . i fi ‘ ae og A c . 2518'5 
25158. 2 Z , 92b1o Ss = é ; 2 ols 
25140 . : : . 25141 . 3 . o e2bI3 SF 
25063. : - . 25066 . ; : . 2506:3 
— = e - . 24783 . fs - : a 
_ 4 5 : . 24348 . A - e 2435°5 
From this it appears that in the spectrum of the arc, carbon yields 
but one line in the ultra-violet, wave-length 2478°3. 
The spectrum of berylliwm.—The researches made for the purpose of 
this Report have been useful in furnishing evidence leading to a determi- 
nation of the probable position of beryllium among the elements. It has 
been proved that the spectra of metallic solutions are identical with 
those of the metals themselves, and it is therefore obvious that charac- 
teristic spectra may be obtained from concentrated solutions of nitrates 
or chlorides when metallic electrodes are not procurable, just as is the 
case with visible spectra. It was resolved to photograph the spectrum of 
beryllium as obtained from its chloride, in order to observe the character 
of its lines and the manner of their grouping. The following were the 
lines observed :-— 
? Proce. Roy. Soc. vol. 33, p. 403. 2 Phil. Trans. vol. 174, Part I. 1883. 
Pp 
8 Transactions, vol. 41, p. 90. 
1883. K ; 
