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IV. On Flame Spectra. 



By OHARLEB DE WATTKVILLB. 



Communicated bi >/ ARTHUR SCHUSTER, F.R.S. 



Received May 28, Read June 16, 1904. 



[PLATE 4.] 



IN the course of a photometrical investigation of flames, which had l>een coloured by 

 injecting the spray from saline solutions into the gas to be burnt, M. GOUY discovered, 

 in the spectra of the flames, several new lines belonging to the metals contained in 

 the solution.* Instead of appearing throughout the whole flame, as did the previously 

 known lines, these new lines were only emitted in the vicinity of the blue inner 

 cone the origin of the Swan spectrum. The observations of M. GOUY were limited 

 to the examination of certain lines of the visible portion of the spectrum, and, with 

 the advice of Professor SCHUSTER and under his direction, I have taken up this study 

 with the object of extending it, by means of photography, to the ultra-violet portion 

 of the spectrum and also of detecting lines which are too feeble to be visible to 

 the eye. 



I. METHOD OF PRODUCING THE FLAME. 



The method employed for the production of the flame is, in short, that which has 

 been introduced by M. GOUY, and described by him in his memoir, to which reference 

 should be made for a more detailed description. The very slight modifications which 

 have been made in the apparatus of this scientist are due to the necessity of having 

 an arrangement which should be as automatic as possible during the eight hours 

 which were often found necessary for the photographic exposures. These modifications, 

 however, have an important bearing upon the success of the experiments. 



Iteferring to the diagram, A is a glass globe, having three necks at B, (J, and D. 

 Into the neck at B is fitted the sprayer P, which consists of two concentric tubes, 

 which have been drawn out together very finely at one end. The inner tube, through 

 which the liquid is blown, is connected by means of indiarubber tubing to the lower 



* ' Ann. ilc- de Chimie et tie Physique,' 5t-h Series, vol. XVIII., 187S). 

 (375.) T 2 12.11.04 



