\o $mUi^ Jets of Liquid issui7ig from Circular Orifices. 287 



past year two different theories were proposed; one by Dejean*, 

 the other by Magnus f. Nevertheless, as I did not find any 

 reference to my theory, and consequently any opposition to it, 

 either in the short analysis which Dejean has given of his still 

 unpublished research, or in Magnus's memoir, 1 resolved to wait 

 and leave its success to time. Another theory, however, has just 

 appeared. In the report presented to the Academy last January {, 

 upon my Third Series §, where I explain the action of vibrations 

 on jets, Maus returns to the constitution of jets not subjected to 

 this action. He declares his inability to adopt my theory, and 

 indicates his reasons for the same; afterwards he developes his 

 own views. As I cannot, under these circumstances, remain 

 longer silent, I propose to compare, as briefly as possible, the 

 three theories above mentioned with my own. 



It is well known that Savart, in his able research on jets of 

 liquid II, after having by ingenious experiments discovered all the 

 peculiarities in the constitution of jets issuing from circular ori- 

 fices, gives an essay on the theory of these phsenomena in the 

 form of a conjecture simply. He attempts to show that the 

 efflux itself imparts a vibratory motion to the liquid in the vessel, 

 and to that which passes through the orifice ; that these vibra- 

 tions or pulsations at the orifice, being perpendicular to the plane 

 of the latter, alternately press out and draw in the liquid as it 

 issues, and thus occasion the annular protuberances or expan- 

 sions whose existence he established, the movement of transla- 

 tion, and the development of, and final conversion into, isolated 

 masses. 



Dejean admits the existence of pulsations, but explains their 

 production differently. In his analysis he does not say to what 

 cause he attributes the separation of the masses which compose 

 the discontinuous part of the jet. 



Magnus, in his very interesting memoir, treats principally of 

 the phsenomena which manifest themselves when two jets meet 

 under certain angles, and of the singular forms of jets issuing 

 from differently shaped orifices. He enters but little into the 

 question of the constitution of jets issuing from circular orifices. 

 He does not assume the existence of pulsations, and in the case 

 of a jet falling vertically and withdrawn from every external 

 influence, he attributes the separation of the mass to the tension 

 resulting from the acceleration in the velocity of the falling 



* Comptes Rendus, vol. xl. p. 46/. 



t PoggendorflF's Annalen, vol. xcv. p. 1 ; and Phil. Mag. for Feb. 1856. 

 X Bull, de I'Acad. de Belgique, vol. xxiii. part 1. p. 4. 

 § We hope to be able to find room for a translation of this Third Series 

 in a future Number of the Magazine. — Eds. 



II Annales de Chimie et de Physique, vol. liii. 1833, p. 33/, 



