W. B. Rogers on Sonorous Flames. 13 
2 pec of —— is directly applicable to the phenomena 
rous fl 
“ces an vadamasienes: series of experiments, Sondhauss has been 
led to similar conclusions as to the mechanical condition of the 
air-jet and has furthermore attempted to bs pen for its vibration, 
as had been previously done by Cagniard-Latour, by the friction 
of the issuing column against the sides of the aperture, aoe 
various important observations recorded in his elaborated m 
moir the following will strike the reader as interesting from its 
analogy with some of the phenomena of singing flames. 
He states that on raksted an n pipe near the aperture we 
erve certain sounds of the pipe ie be scam panied by a secondary 
sound produced by the air-jet Manich 1 ts either in unison with that of 
pipe or an octave below it. Have we not here an exact counter- 
part of the beautiful experiment of Tyndal and Schaffgotsch, in 
which the silent plane is made to sing by sounds of a certain 
pitch produced in its vicinity? Alluding to this observation of 
Sondhauss, Masson suggestively remarks, “ that the fact seems to 
him to admit of no other eevee: g than that which Savart 
has given of the influence of external sounds on liquid jets.” 
It should be added that both Masson and Sondhauss have 
roved that neither the material of the aperture nor its shape 
ve any influence on the cause which produces the sonorous 
co ee of the air-jet. 
above brief reference to the discoveries of Savart oa 
those Ses have followed in the same line of investigation is 
care ms show that jets of air under the pgs ere of oe - 
and doubtless all air-jets, in egree, are, at 
Dae or efflux, capes with a ee or poate 
movement, and that this is the primary source oF the vibration in 
singing 
fr g flames of these facts we may describe the principal phases in in 
production of the singing flame, briefly as follows 
First. Every jet of gas and therefore of flame is ot al ae Se 
the seat of a vibratory motion, but under ordinary circumstances 
this is too feeble to produce either audible or visible effects. 
Second. When the jet is placed in conditions to favor an ox 
plosive combustion the remissions and intensions of the jet due 
to the vibratory motion, render the explosions more or less dis- 
continuous, and thus add greatly to the energy of the aoa atc 
Third. These vibra pain: Rem ae explosive flame occ 
within a resonant tube of suitable ions, me oe 
and re-enforced, until eqeeamen the mutual aokon of the vibrat- 
jet and ihe air column a is produced co corresponding 
more or less nearly to the faBaxisentnl note, or one of the har- 
monics of the tube. 
