1893.] Flame Spectra at Higli Temperatures. 



II. " Flame Spectra at High Temperatures. Part I. Oxy- 

 hydrogen Blowpipe Spectra." By W. N. HARTLEY, F.R.S. 

 ' Received May 10, 1893. 



(Abstract.) 



Brewster, in 1842, first examined the spectra of salts with a flame 

 of oxygen and coal-gas ('Proc. Roy. Soc. Edin.,' vol. 6, p. 145). 



Professor Norman Lockyer has given us maps of twenty-two 

 metallic spectra at tbe temperature of the oxygen and coal-gas flame. 

 The region observed lies between X 7000 and 4000. 



Preparatory to undertaking the study of spectroscopic phenomena 

 connected with the Bessemer " blow " and the manufacture of steel 

 generally, I have carefully observed the spectra of metals and metallic 

 oxides obtained by submitting the substances to the oxyhydrogen 

 flame. 



Method of Investigation. The method of obtaining spectra with 

 flames at high temperatures is the following. Hydrogen proceeding 

 from a large lead generator is burnt in a blowpipe with compressed 

 oxygen. Tbe blowpipe measures 3 in. in length by f in. external 

 diameter. The substances examined are supported in the flame on 

 small plates of kyanite about 2 in. in length, -^ in. in thickness, and 

 J in. in width. This mineral, which is found in masses in Co. 

 Donegal, contains 96 per cent, of aluminium silicate, and is prac- 

 tically infusible. The spectra were all photographed with the instru- 

 ment employed by me on former occasions for photographing ultra- 

 violet spectra, illustrations of which were published in the ' Chem. 

 Soc. Journ.,' vol. 41, p. 91, 1882. The dispersion of the instrument 

 was that of one quartz prism of 60. 



Isochromatic plates developed with hydroquinone were largely 

 used. Various dyes for sensitising and all kinds of developing sub- 

 stances were tried. The spectra were measured with an ivory scale 

 divided into hundredths of an inch, and directly applied to the photo- 

 graphs, the division 20 on the scale being made to coincide with the 

 yellow sodium line which appears in every photograph. It was 

 found convenient to record the measurements on a gelatino-bromide 

 paper print taken from an enlarged negative. Sometimes, for more 

 careful and minute reference, it was found convenient to make an 

 enlargement of the spectrum with the scale in position, but accurate 

 measurements cannot be made in this way. It is necessary to use a 

 low magnifying power and cross wires in the eye-piece. 



For the identification of lines already known nothing more com- 

 plicated is required, but to measure new lines and bands it was con- 

 sidered desirable to make use of a micrometer and microscope, the 



