influence of Vibratory Motions. 21 
Except in the particular case of a very small interval between 
the note of the instrument and that of the jet, Savart says nothing 
of the periodic changes of the continuous part; neither should 
he have done so, as we shall presently see. For intervals which 
do not fulfil the above condition, these changes are too rapid for 
the succession to be distinguished, so that all the lengths, as well 
as all the systems of ventral segments respectively corresponding 
to these lengths, ought to appear simultaneously ; hence, under 
these circumstances, each of the ventral segments of the jet 
ought to appear formed of individual ventral segments not ex- 
actly superposed, and consequently (§ 8) to present the aspect 
of an assemblage of waves. But this aspect was not new to 
Savart, for he had observed it ($ 10) in the ventral segments of 
jets not submitted to the influence of a sonorous instrument. 
§ 14. The three remaining conclusions in paragraph 12 appear 
to be confirmed by No. 8 of paragraph 3. Nevertheless, the 
manner in which Savart mentions the facts might throw some 
doubt upon the perfect exactitude of thisaccord. The following 
passages of Savart’s memoir are the only ones which refer to the 
facts in question :— 
“The octave and fifth below the note produced by the shock 
of the discontinuous part against a body employed for strength- 
ening the tone, as well as its minor third, augmented fourth, 
and the octave above, produce upon the jet modifications analo- 
gous to those just described*, but always with much less energy ; 
and there are notes which have no influence whatever upon the 
dimensions of the jet and the aspect it presents.” 
Subsequently, when speaking of a jet received at a small di- 
stance from the orifice upon a thick solid body, he says,— 
“Just as when the jet is entire, we find that the octaves above 
and below, as well as the fifth and minor third above the note in 
question}, also influence the state of the jet, though to a less 
degree.” 
Lastly, with reference to the modifications experienced by a jet 
under the influence of a note in unison with that dune to the 
shock of the discontinuous part against a stretched membrane, 
but protected from every other foreign influence, he remarks 
that— 
“ Analogous results are obtained when divers notes are pro- 
duced upon a stringed instrument in the neighbourhood of the 
reservoir, but one of these notes always exercises a greater influ- 
ence upon the jet than any of the others.” 
Do these passages imply, that, besides the unison, only the 
octave and fifth below, the minor third, the augmented fourth and 
* That is to say, to those produced by unison. 
+ That natural to the jet. 
