296 (M Jfh of Liq\dd isming from Circular Orifices. 



which the tabulated observations of the ilhistrious French philo- 

 sopher fnlly contirWr ''i' '>»*^ ^^^ ^^'>' «' l»n»pfl o/lr ,Hoi,tom y;fot.;i • 

 I have still to establish 'thfeC«il*edon<%etwkn«i^4h(eory'aiifd 

 the T^hanomcna resulting from the influence of tones ; as already 

 stated, this was done in my Third Series. When vibrations are in 

 reality communicated to the vessel and the liquid it contains, the 

 principle of pulsations at the orifice ceases to be a vague and 

 improbable hypothesis, and becomes almost a certainty. Now I 

 "have demonstrated that when the tone which acts upon the jet 

 is exactjy in unison mth the one which the shock of the discon- 

 tinuous part against a stretched membrane would produce, the 

 expansions and contractions causied by th(, vibrations executed at 

 the orifice coincide perfectly with the expa:isions and contractions 

 due to the molecular forces, so that there is absolute concuiTcnce 

 between the two actions. From this simple principle I have 

 afterwards deduced the explanation of all the phjenomena ob- 

 served by Savart. 



If, in this collection of theoretical researches, I have had 

 V recourse to hypotheses, they are purely accessory, and serve only 

 « to explain certain facts too complicated to admit of our appre- 

 1 dating th6 action of the several elements concerned in their pro- 

 - duction. 



.^ Let us pass, lastly, to the arguments upon which Maus bases 

 ■a' his opposition^ - They are stated in the Idbwing passage of the 

 ^gxeport :— i^^'^'to ^-ooiif'to '!>> s'lC'drltrTi fsih '\o ^ fivn t H-mH// jMUfMi:' 



8'* ''I find it difficult to admit, with Plateau, that in a 



s^phsenomenon principally produced by gravity, this force ought 

 to be completely eliminated in order to attribute the configura- 

 -ration of the moving mass exclusively to molecular forces, which 

 8'' are far inferior to gravity. '« ^/ .ofo/i/r« «fi ffoitj'^jgri ^'jinii 

 3ii " My hesitation increased when if6?andv'that^ iii 6rder'to jtis- 

 n'tify the elimination of gravity, Plateau considered this force as 

 only acting upon the jet when leaving the orifice, without con- 

 sidering its action upon the liquid contained in the vessel ; which 

 action, by its manner of attracting the liquid molecules towards 

 the orifice, exercises upon the form of the jet an influence which 

 cannot be doubted when we consider the phsenomena known as 

 the contraction and inversion of a jet. 



• ^f'The beautiful experiments with jets of liquid, repeated every 



year by Prof. Richelmi at the hydraulic establishment of LaParella 



near Tui-in, havmg shown me a kind of opposition between ori- 



i; flees of different shapes and the profiles which they produce in 



o; the jet at a short distance from them, have not prepared me for 



Qii disregarding the interior action on the form of the jet.^fj^ ; 



It is impossible to find real objections here. Without doubt 

 gravity causes the liquid to leave the vessel and thus produce 



