WITHDRAWN FROM THE ACTION OF GRAVITY. — 331 | 
§ 26. Now, a vein being projected under such an angle that the sheaf shall 
be well formed, let us submit it to the influence of a sonorous instrument. The 
sound which will most shorten the continuous part will still be evidently that 
whose vibrations succeed one another at the same intervals which the constric- 
tions and dilatations due to the configurative forces (§§ 5 and 12) observe in 
their passage at the contracted section. But these vibrations being perfectly 
regular and isochronous, they will prevent, if they have sufficient intensity, 
the disturbing causes from modifying the incipient constrictions; in other terms, 
in influencing the transformation, they will impart to it their own regularity, so 
that all the incipient constrictions will have the same length, and henee all 
the isolated masses will follow identically the same trajectory (§ preceding ;) 
under the influence of this sound the sheaf will disappear, and the whole of 
the vein be reduced to a single jet presenting a very regular system of expan-_ 
sions and nodes. 
§ 27. As to the singular effects of reduction of the sheaf to two or three jets 
under the influence of other sounds, it would be necessary, in order to attempt 
an explanation, to know the relations of the sounds in question with the princi- 
pal ones—relations which Savart nowhere indicates. But as these phenomena 
are not the least curious of those which result from the action of vibrations on 
liquid veins, I have decided to attempt this investigation. 
The orifice I employed had a diameter of 5 millimetres; it was pierced in 
the centre of a circular plate of brass of 12 centimetres diameter,* so inclined 
that the jet might be projected at an angle of about 35° above the horizontal ; 
this plate formed one of the bases of a cylindrical drum which communicated 
by a horizontal tube, wide and short, with the lower part of one of Mariotte’s 
large vases; the discharge was of 34 centimetres, the sonorous instrument was 
a violoncello, the base of which was made to rest on the supports of the ap- 
paratus. 
The’ sheaf being well developed, the attempt was made in the first place to 
ascertain by approaches the principal sound, or, in other words, that which pre- 
cisely reduced the whole vein to a single jet with a regular system of expan- 
sions and nodes, and which, at the same time, caused the first expansion to arise 
very near the orifice. This point being attained, the sound of the instrument 
was raised by successive semi-tones. Under the influence of the vibrations 
thus communicated, the jet first lost its regularity, next the sheaf gradually 
reappeared, and afterwards was maintained without being reduced to either two 
or three jets. A return was then made to the principal sound, and from that 
point the sound of the instrument was caused to descend, likewise by semi- 
tones. The same effects, the alteration, namely, of the regularity of the jet 
and the progressive reappearance of the sheaf, were now manifested; but, on 
approaching the grave octave, a tendency to the change of the sheaf into a 
double jet was remarked, and when this last sound was reached, the sheaf was 
distinctly replaced by two jets with regular systems of expansions and nodes. 
The sound continued to be lowered, and the two jets still to appear, until the 
third below the grave octave was attained ; still lower, and so long as the double 
grave octave was not reached, sometimes two and sometimes three jets were 
obtained ; the fifth, however, sometimes -yielded a single jet; finally, for the 
double grave octave, three jets were constantly observed. In all these cases, 
the jets continued each to have its system of expansions and nodes. 
These facts are less restricted than those stated in No. 16 of § 3; according 
to that number, in which the purport of Savart’s expressions is reproduced, it 
* A diameter so considerable was employed from the necessity of leaving sufficient liberty 
to the vibrations of the plate. Without that liberty, the vibrations of the liquid which flows 
towards the orifice would be impeded, and would hence lose some of their action on the vein. 
