THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[FOURTH SERIES.] 



AUGUST 1866. 



XII. Flame Reactions. By R. Bunsen*. 



[With a Plate.] 



ALMOST all the reactions which can be performed by means 

 of the blowpipe may be accomplished with far greater ease 

 and precision in the flame of the non-lnminous gas-lamp. This 

 flame, moreover, possesses several peculiarities which render it 

 available for reactions by which the smallest traces of many sub- 

 stances occurring mixed together can be detected with certainty 

 when the blowpipe and even still more delicate methods fail. 



The number of new reactions which can in this way be per- 

 formed is so large that I am only able here to mention the most 

 important, leaving it to those who wish to make themselves ac- 

 quainted with this subject to apply the same principles to other 

 cases, and to follow out this method in other directions. 



I. The Structure of the Non-luminous Gas-elame. 



The gas-lamp with non-luminous flame used for these reac- 

 tions is represented in fig. 1, Plate I., and must be made, exactly 

 to scale, 3J times as large as the drawing. It must be furnished 

 with a cap at a for closing and opening the draught-holes, so as 

 to be able to regulate the supply of air for every dimension of 

 the flame. The conical chimney dddd, fig. 2, must also be 

 made of such a size that the flame burns perfectly steady. 



Fig. 2 represents this flame of its natural size. It is com- 

 posed of the following three chief divisions : — 



A. The dark cone, a a a, containing the cold unburnt gas mixed 

 with about 62 per cent, of atmospheric air. 



B. The flame-mantle, a cab, formed of the burning coal-gas 

 mixed with air. 



* Translated by Professor Roscoe, F.R.S., from the Annalen der Chemie 

 undPharmacie, vol. cxxxviii. p. 257. 



Phil. Mag. S. 4. Vol. 32. No. 214. August 1866. G 



