434 M. J. Plateau on Jets of Liquid under the 
small amplitude, and if it is held at a great distance from the 
orifice, it may occur that the relative velocity of the impulses 
always continues to be considerable; so that the intensity of the 
jet’s note is sensibly uniform, whilst that of the body’s, even 
when greatest, is not able to overpower it. The former will 
then always be perceptible, and consequently during the most 
intense periods of the latter, both notes will be heard at the 
same time. Without doubt it is thus that we must interpret 
the words or even simultaneously, which are taken literally from 
Savart. 
§ 17. Let us reconsider the case where a note in unison with 
that of the jet is produced by an instrument. If the latter, 
stead of acting at a distance, is placed in contact with the 
sides of the vessel from which the jet issues, it is evident that 
the vibrations communicated to these sides and propagated in 
the liquid will be much more energetic, and consequently that 
the modifications of the jet will be much more developed ; more- 
over, it is manifest that the small irregularities of which we have 
spoken in paragraph 10 may then be entirely effaced. The con- 
tents of No. 11 of paragraph 3, therefore, require no further 
explanation. 
§ 18. According to No. 12 of paragraph 3, another system of 
shorter and thinner ventral segments and nodes is now observ- 
able in the axis of the jet from the lower extremity of the conti- 
nuous part downwards, which system, as Savart remarks, is due 
to the spherules that accompany the masses. 
An apparent difficulty here presents itself. When the jet is 
protected from all vibratory action, its troubled part is free from 
ventral segments and nodes; it would appear, therefore, that ° 
under the sole action of the forces of figure, the masses arrive at 
the spherical form without executing sensible oscillations, and 
that oscillations of form take place solely in the cases where the 
forces of figure are activated by vibrations. Now the production 
of the spherules cannot in any manner be influenced by the vibra- 
tions; for the latter only act directly at the contracted section, 
their effect below this section being limited to acquired velocities 
($$ 6 and 8) which accelerate the development of the expansions © 
and contractions, and the subsequent conversion of each of the 
latter into a thread. The transformation of this thread, whence 
result the spherules, is effected solely by the forces of figure 
which are generated therein, as in every other sufficiently elon- 
gated cylinder of liquid; nevertheless these spherules execute 
oscillations of form, as is proved by the appearance of ventral 
segments and nodes presented by their passage before the eye. 
In order to elucidate this point, let us attentively examine the 
<ircumstances relative to these spherules and to the large masses, 
a 
