1879.] 



On the Capillary Phenomena of Jets. 



71 



VI, " On the Capillary Phenomena of Jets." By Lord Rayleigh, 

 F.R.S. Received May 5, 1879. 



When water issues under high pressure from a circular orifice in a 

 thin plate, a jet is formed whose section, though diminished in area, 

 retains the circular form. But if the orifice be not circular, the section 

 of the jet undergoes remarkable transformations, which were elabo- 

 rately investigated by Bidone,* many years ago. The peculiarities of 

 the orifice are exaggerated in the jet, but in an inverted manner. 

 The following examples are taken from Bidone's memoir. 



Fig. 1. 



M 



r\ 



D 



Fig. 1, orifice in the form of an ellipse (A), of which the major 

 axis is horizontal, and 24 lines long ; the minor axis is vertical, and 17 

 lines long. The head of water is 6 feet. 



Near the orifice the sections of the vein are elliptical with major 

 axis horizontal. The ellipticity gradually diminishes until at a distance 

 of 30 lines from the orifice the section is circular. Beyond this 

 point the vertical axis of the section increases, and the horizontal axis 

 decreases, so that the vein reduces itself to a flat vertical sheet, very 

 broad and thin. This sheet preserves its continuity to a distance of 

 6 feet from the orifice, where the vein is penetrated by air. 



B represents the section at a distance of 30 lines from the orifice. 

 It is a circle of 16 or 17 lines diameter. 



C is the section at a distance of 6 inches from the orifice. It is an 



* " Experiences sur la Forme et surla Direction des Veines et des Courans d'Eau 

 lances par diverses Ouvertures." Par George Bidone. 



