[280 j 
XIX. 
ON THE OCCURRENCE OF CYANOGEN COMPOUNDS IN 
COAL-GAS, AND OF THE SPECTRUM OF CYANOGEN 
IN THAT OF THE OXY-COAL-GAS FLAME. By W. N. 
HARTLEY, F.R.S., Royal College of Science, Dublin. 
[Read Frpruary 21; Received for Publication Frpruary 23 ; 
Published Aprin 6, 1900.] 
_ In a memoir’ giving an account of an elaborate investigation, by 
Messrs. Eder and Valenta, of the spectrum of the flame afforded by 
coal-gas when supplied with oxygen, the authors remark that one 
of them had discovered the ultra-violet spectrum of the inner blue 
cone of the flame of a Bunsen burner in 1886, and in 1890 had 
published photographs of the visible and ultra-violet emission 
spectrum of feebly illuminating hydro-carbon flames with wave- 
length measurements of the principal lines and bands. They state 
that the spectrum of the oxy-coal-gas flame, described by me in 
“Flame Spectra at High Temperatures,” Part I., ‘“ Oxyhydrogen 
Blow-pipe Spectra” (Phil. Trans., vol. 185, p. 16, 1894), contains a 
list of measurements of lines and markings on the bands, which are 
erroneous to the extent in some cases of five-tenth metres in wave- 
length, and that no regard was paid to the work mentioned above. 
It may here be explained that I was quite unaware of this work at 
the time, and, moreover, the spectrum of the oxy-coal-gas flame 
was photographed and described by me in 1888-89, and therefore 
anterior to its date of publication. The account of it formed a 
small part of a long communication made to the Royal Society in. 
1893, and was intended as a study preliminary to the fuller 
examination of the flame spectra of metals and metallic oxides; also 
of flames arising from metallurgical operations, such as the 
Bessemer and open-hearth steel processes. The lines and bands to 
the number of 111 observed in the oxy-coal-gas flame when using 
a single quartz prism, and a ‘‘ somewhat wide slit’’’ (see p. 170, 
1 Denkschr. K. Akad. Wiss. Wien. Vol. 67, Sept., 1898. Also Beiblatter, 
Wiedemann’s Annalen, vol. 23, p. 557, Sept., 1899. 
2 On p. 2 of Eder and Valenta’s paper, these words are wrongly translated—‘‘ Mit sehr 
weitem Spalte,’? which is a departure from the true meaning and from the actual fact. 
Y¥ 2 
