349 



experiments were found to be unexpectedly interesting and 

 beautiful. 



(3.) As in the above cases the action is mainly traceable to 

 the moi'e rapid mingling of atmospheric air with the flame, it is 

 natural to conclude that a like effect would be produced by pass- 

 ing a current of air upwai'ds through the tube, and on trial this 

 anticipation was strikingly verified. In order that the current 

 may be evenly distributed, it is convenient to employ an argand 

 burner, having the supply pipe at the side, and the central open- 

 ing entirely free, so that the jet pipe may rise thi'ough the centre 

 and the burner be adjusted to the proper distance below the 

 flame and the bottom of the glass tube. The air conveyed to the 

 argand burner through a flexible pipe, may be supplied either 

 from the lungs of the operator or from an adjacent gasometer. 

 In most cases the action of the current is more easily managed 

 when the apertures from which it flows are some two or three 

 inches below the bottom of the resonant glass tube. 



With this arrangement, and a proper graduation of the current 

 of air impelled into the tube, we can cause the flame to sing when 

 the other methods above described have failed to produce any 

 effect. When the flame is not far from the position in which it 

 would spontaneously sing, the lightest breathing through the argand 

 jpipe is sufficient to bring it to the sounding state, and to maintain 

 a clear, smooth tone. Even when the flame is large and other- 

 wise not readily susceptible of the sonorous action, a stronger cur- 

 rent of air applied nearer to the bottom of the resonant tube will 

 rarely fail to bring on the musical vibrations. It should be men- 

 tioned that these effects can be produced in a simpler but less 

 satisfactory manner by using, instead of the argand burner, to 

 conduct the current, a common glass tube, bent suitably, and held 

 near the jet pipe below the opening of the resonant tube. 



The sound familiarly observed wlien a flame of any kind is 

 blown upon, and especially when the air is forced into or through 

 the flame, as in the case of the jet of a blow-pipe, was long ago 

 referred by Faraday to the combustion of an explosive mixture 

 formed by the air and burning matter. The sound produced by 

 a blazing fire of wood or bituminous coal, as contrasted with the 

 silence of a flameless mass of ignited anthracite, is an obvious illus- 

 tration of the same principle. But the experiments above de- 



