Vibrations on Gaseous and Liquid Jets, 



377 



steadily, refusing to respond to any sound, musical or unmusical. 

 I urge against the broad face of the flame a stream of air from a 

 blowpipe. The flame is cut in two by the air ; and now, when 

 the whistle is sounded, it instantly starts. A knock on the table 

 causes the two half-flames to unite and form for an instant a 

 single flame of the ordinary shape. By a slight variation of the 

 experiment, the two side flames disappear when the whistle is 

 sounded, a central luminous tongue being thrust forth in their 

 stead. 



Before you now is another thin sheet of flame, also issuing 

 from a common fish-tail burner (fig. 3). You might sing to it, 

 varying the pitch of your voice ; no shiver of the flame would be 

 visible. You might employ pitch-pipes, tuning-forks, bells, and 

 trumpets, with a like absence of all effect. A barely perceptible 

 motion of the interior of the flame may be noticed when this 

 shrill whistle is blown close to it. By turning the cock more 

 fully on I bring the flame to the verge of flaring. And now, 

 when the whistle is blown, you see an extraordinary appearance. 

 The flame thrusts out seven quivering tongues (fig. 4) . As long 

 as the sound continues, the tongues jut forth, being violently agi- 

 tated; the moment the sound ceases, the tongues disappear and 

 the flame reassumes the form of fig. 3. 



Fig. 3. 



Fig. 4. 



Passing from a fish-tail to abatVwing burner, we obtain this 

 broad steady flame (fig. 5) . It is quite insensible to the loudest 

 sound which would be tolerable here. The flame is fed from 

 a small gas-holder, which places a greater pressure at my 



