2. Each of the masses, as they detach themselves from the extremity of the continuous part, becomes flattened alternately in a vertical and horizontal direction, presenting to the eye, under the influence of their translatory motion, regularly-disposed series of maxima and minima of thickness, or ventral segments and nodes. 3. The foregoing modifications become much more developed and regular when a note, in unison with that which would be produced by the shock of the discontinuous part of the jet against a stretched membrane, is sounded in its neighborhood. The continuous part becomes considerably shortened, and the ventral segments are enlarged. 4. When the note of the instrument is _almost_ in unison, the continuous part of the jet is alternately lengthened and shortened and the beats which coincide with these variations in length _can be recognized by the ear_. 5. Other tones act with less energy on the jet, and some produce no sensible effect. When a jet is made to ascend _obliquely_, so that the discontinuous part appears scattered into a kind of _sheaf_ in the same vertical plane, M. Savart found: _a._ That, under the influence of vibrations of a determinate period, this sheaf may form itself into _two_ distinct jets, each possessing regularly-disposed ventral segments and nodes; sometimes with a different node the sheaf becomes replaced by _three_ jets. _b._ The note which produces the greatest shortening of the continuous part always reduces the whole to a _single_ jet, presenting a perfectly regular system of ventral segments and nodes. In the last memoir of M. Savart—a posthumous one, presented to the Academy of Sciences of Paris, by M. Arago, in 1853[85]—several remarkable acoustic phenomena are noticed in relation to the musical tones produced by the efflux of liquids through short tubes. When certain precautions and conditions are observed (which are minutely detailed by this able experimentalist), the discharge of the liquid gives rise to a succession of musical tones of great intensity and of a peculiar quality, somewhat analogous to that of the human voice. That these notes were not produced by the descending drops of the liquid vein was proved by permitting it to discharge itself into a vessel of water, while the orifice was below the surface of the latter. In this case the jet of liquid must have been _continuous_, but nevertheless the notes were produced. These unexpected results have been entirely confirmed by the more recent experiments of Prof. Tyndall.[86]