_ W. B. Rogers on Sonorous Flames. 7 
duced by a blazing fire of wood or bituminous coal contrasted 
with the silence of a flameless mass of ignited anthracite is an 
obvious illustration of the same principle. But the experiments 
above described show the operation of this law under conditions 
which enable us more satisfactorily to mark the origin of the 
sound and the aero by which it accompanies the formation 
of the explosive mixture 
3. The sonorous state may be induced by causing an additional 
supply of air to pass up the resonant tube.—As in the above cases 
the action was mainly traceable to the more rapid mingling of 
the atmospheric air with the flame, it was natural to conclude 
that a like — would be “oan ett: by passing a current Of, air 
i 
the bottom of he resonant glass tube. Fig. 1, B, represents. 
the air Jet in connection with the other parts as adjus for ex- 7 
perimen: . 
j an Se arrangement and a proper graduation of the current 
ame 
ra current ots sey 
nant <—. Sagan 
the experiment “Wh en the resonant tube is of moderate s size, 
for example, three-fourths of an inch or an Sach in diameter, 
af the =e rex than is : suited to spontaneous 
in other words | 
manageable if made to ascend from a distance of two or three : 
inches below the oes of the tube. Using a much larger” 
_ flame in the same tube, we must of course apply a stronger cur- _ 
rent to Supply the requisite amount of air, and must therefor Z 
