148 Scientific Intelligence. 



SCIENTIFIC INTELLIGENCE. 



I. Physics. 



1. Flame Spectra at High Temperatures. Part I. Oxy- 

 hydrogen Blowpipe Spectra, by W. N. Hartley. (Abstract, re- 

 ceived from the author, of a paper presented to the Royal Society, 

 May 10, 1893.) — Brewster, in 1842, first examined the spectra of 

 salts with a flame of oxygen and coal-gas (Proc. Roy. Soc. Edinb., 

 vol. vi, p. 145). Professor Norman Lockyer has given us maps 

 of twenty-two metallic spectra at the temperature of the oxygen 

 and coal-gas flame. The region observed lies between X 7000 

 and 4000. 



Preparatory to undertaking the study of spectroscopic phenom- 

 ena 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 pro- 

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

 compressed oxygen. The blowpipe measures 3 inches in length 

 by § inch external diameter. The substances examined are sup- 

 ported in the flame on small plates of cyanite about 2 inches in 

 length, -Jq i n ch in thickness, and \ inch in width. This mineral, 

 which is found in masses in Co. Donegal, contains 96 per cent of 

 aluminium silicate, and is practically infusible. The spectra 

 were all photographed with the instrument employed by me on 

 former occasions for photographing ultra-violet spectra, illustra- 

 tions of which were published in the Chem. Soc. Journ., vol. xli, 

 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 sensitizing and all kinds of developing 

 substances were tried. The spectra were measured with an ivory 

 scale divided into hundredths of an inch, and directly applied to 

 the photographs, the division 20 on the scale being made to coin- 

 cide with the yellow sodium line which appears in every photo- 

 graph. 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 measurement 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 

 complicated is required, but to measure new lines and bands 

 it was considered desirable to make use of a micrometer and 

 microscope ; the screw of the micrometer was cut with 100 threads 



