AMERICAN 



JOURNAL OF SCIENCE AND ARTS. 



[THIRD SERIES.] 



Art. XXXVII.— On Vortex Rings in Liquids; by John Trow- 

 bridge, S.D., Assistant Professor of Physics. (O- 

 from Physical Laboratory of Harvard College. No. XVIII.) 

 [Presented at the Meeting of.the Am. Acad, of Arts and Sciences, Mar. 14, 1877.] 



_ It has often been observed by chemists that a drop of colored 

 liquid falling from a burette into a liquid of a different specific 

 gravity, in which it can diffuse, assumes the form of a ring. 



Vortex motion, by the researches of Helmholtz, Thomson, Ran- 

 kine, and Maxwell, is now attracting so much attention, that I 

 have thought that a study of the general equations of motion 

 of matter in connection with a study of these rings would con- 

 tribute to our knowledge of vortex movement. 



Prof. W. B. Rogers published in this Journal, xxvi, 1858, a 

 paper on smoke rings and liquid rings, and described several 

 methods of studying them. In Professor Tail's "Recent Ad- 

 vances in Physical Science," a method of forming smoke nngs 

 is given. The apparatus consists merely of a large box closed 

 at one end by a thin sheet of india rubber, or with a tightly 

 stretched towel, and having a circular opening of six or eight 

 uches in diameter at the other. Clouds of sal-ammoniac vapor 

 are generated inside the box, and rings are expelled from the 

 opening by a blow upon the rubber or towel, fair 

 Willi am Thomson suggests that two such boxes placed so that 

 the rings may impinge on each other at any angle would form a 

 useful apparatus for studying the behavior of such rings toward 

 each other. At the conclusion of this paper, several methods 

 of studying liquid rings will be described. When a drop of 

 Muid falls from a short distance into a liquid of less density, 



Am- Joub. Sci—Thibd Series, Vol. XIII, No. 77,-May, 1877. 



