444 M. J. Plateau on Jets of Liquid under the 
§ 27. With respect to the singular effects whereby, under the 
influence of other notes, the sheaf is reduced to two or three jets, 
it would be necessary, before attempting an explanation, to know 
the relation between the notes in question, and the principal 
note; which relation Savart does not indicate. On this account, 
and because these phenomena are not the least curious amongst 
those which result from the action of vibrations upon jets of 
liquid, I decided to attempt the experiment. 
The orifice I employed had a diameter of 3 millims. ; it was 
made at the centre of a circular brass plate 12 centimetres in 
diameter*, so inclined that the jet issued upwards at an angle of 
about 35° to the horizon ; this plate formed one of the bases of a 
cylindrical drum, which communicated by a wide and short hori- 
zontal tube with the lower part of a large Mariotte’s vessel; the 
charge amounted to 34 centimetres ; lastly, the sonorous instru- 
ment was a violoncello, the bottom of which rested on the sup- 
ports of the apparatus. 
The sheaf being well formed, repeated trials were made to find 
the principal note, or that which completely reduced the whole 
to a single jet with a well-regulated system of ventral segments 
and nodes, and which at the same time originated the first ven- 
tral segment very near the orifice. This being accomplished, 
the pitch of the instrument’s note was raised by successive semi- 
tones. The influence of the vibrations was then found to dimi- 
nish, the jet commenced to lose its regularity, afterwards the 
sheaf gradually reappeared, and then it remained without be- 
coming reduced to either two or three jets. The principal note 
was next reproduced, and starting from it, the note of the in- _ 
strument lowered im pitch by semitones. Again the alteration 
in the jet’s regularity, and the progressive reappearance of the 
sheaf, manifested themselves; but on approaching the octave 
below, the sheaf showed a tendency to become changed into a 
double jet, and on arriving at the latter note the sheaf was de- 
cidedly replaced by two jets with regular systems of ventral seg- 
ments aud nodes. On continuing to lower the pitch of the note 
down to a third below the octave above mentioned, the two jets 
continued unaltered ; lower still, and before reaching the second 
octave, sometimes two, sometimes three jets were obtained ; the 
fifth alone occasionally gave a single jet; at length with the 
second octave below the principal note, three jets were always 
observed. In all these cases the jets invariably presented systems 
of ventral segments and nodes. 
* The object of this large diameter was to allow sufficient hberty to the 
vibrations of the plate ; without which liberty, indeed, the vibrations of the 
liquid flowing towards the orifice would be impeded, and would thus lose 
their action on the jet. 
