Vibrations on Gaseous and Liquid Jets. 389 



for the full development of the continuous portion of the vein ; 

 still Savart was so far able to withdraw his vein from the influ- 

 ence of such irregular vibrations that its limpid portion became 

 elongated to the extent shown in fig. 19. Fig. 17, it will be 

 understood, represents the vein exposed to the irregular vibra- 

 tions of the city of Paris, while fig. 19 represents a vein pro- 

 duced under precisely the same conditions, but withdrawn from 

 those vibrations. 



The drops into which the vein finally resolves itself are inci- 

 pient even in its limpid portion, announcing themselves there as 

 annular protuberances, which become more and more pronounced, 

 until finally they separate. Their birthplace is the orifice itself; 

 and under even moderate pressure they succeed each other with 

 sufficient rapidity to produce a feeble musical note. By permit- 

 ting the drops to fall upon a membrane, the pitch of this note 

 may be fixed ; and now we come to the point which connects the 

 phenomena of liquid veins with those of sensitive flames and. 

 smoke-jets. If a note in unison with that of the vein be sounded 

 near it, the limpid portion instantly shortens : the pitch may vary 

 to some extent, and still cause a shortening ; but the unisonant 

 note is the most effectual. Savart's beautiful experiments on 

 vertically descending veins have recently been repeated in our 

 laboratory with striking effect. From a distance of 30 yards 

 the limpid portion of a vein has been shortened by the sound 

 of an organ -pipe of moderate intensity but of the proper pitch. 



The excellent French experimenter also caused his vein to issue 

 horizontally and at various inclinations to the horizon, and found 

 that in certain cases sonorous vibrations were competent to 

 cause a jet to divide into two or three branches. In these ex- 

 periments, the liquid was permitted to issue through an ori- 

 fice in a thin plate. Instead of this, however, we will resort to 

 our favourite steatite burner ; for with water also it asserts the 

 same mastery over its fellows that it exhibited with flames and 

 smoke-jets. It will, moreover, reveal to us some entirely novel 

 results. By means of an india-rubber tube the burner is con- 

 nected with the water-pipes of the Institution, and by pointing 

 it obliquely upwards, we obtain a fine parabolic jet, fig. 20. At 

 a certain distance from the orifice, the vein resolves itself into 

 spherules, whose motions are not rapid enough to make the vein 

 appear continuous. At the vertex of the parabola the spray of 

 drops is more than an inch in width, and further on they are 

 still more widely scattered. On sweeping a fiddle-bow across a 

 tuning-fork of the proper pitch, the scattered drops, as if drawn 

 together by their mutual attractions, instantly close up and form 

 an apparently continuous liquid arch some feet in height and span, 

 fig. 21. As long as the proper note is maintained the vein looks 



