02 Prof. Magnus's Hydraulic Researches. 



jetSj and is no longer plane, but somewhat curved; neither is it 

 circular, but extended for the most part in that direction in which 

 it would be cut by a plane passing through the axes of both jets. 

 Such a surface is shown in tig. 3, Plate I. 



Savart does not appear to have observed this phainomenon, 

 but only that which manifests itself when two jets of different 

 diameters and parallel axes meet one another*. Neither has he 

 occupied himself with the phaenomena which are observable when 

 the axes of the two jets are inclined to one another. 



7. As it will often be necessary in what follows to distinguish 

 the case when the axes of the jets are in the same plane from 

 that when jets, whose axes do not intersect, encounter one an- 

 other, I will, for the sake of brevity, call the encounter of two 

 jets whose axes cut one another a central encounter, no matter 

 whether they are parallel or inclined to one another. 



Experiments with Jets of equal diameters. 



8. In the following experiments, wherein the jets were always 

 inclined towards each other, jets of different diameters were also 

 employed ; nevertheless, the phsenomena attending the encounter 

 of two jets issuing with equal velocities from two equal orifices 

 shall be first described. When the axes of two such jets, ab and 

 Oibj, fig. 4, lay in the same plane, that is to say, when a central 

 encounter took place, a water surface was produced perpendicular 

 to the plane passing through both axes ; and if both jets had the 

 same velocity at the place of meeting, the surface bisected the 

 angle made by the jets. 



This surface, however, was not equally distributed around the 

 place of meeting, but was elongated principally in the direction 

 of the motion of the jets. Fig. 4 shows the form of the surface 

 when horizontal jets were employed. 



9. The more acute the angle made by the jets, the smaller is 

 the part bq of the surface within this angle. For instance, when 

 the apertures from which the jets issued had a diameter of 3 mil- 

 ]ims., and the axes formed a right angle, the surface extended 

 itself within the angle aboj, so as to form the part bq, fig. 4. 

 When the angle between the jets, however, amounted to 60°, 

 the surface within the angle ftbui, as shown in fig. 5, no longer 

 existed, neither was it observable when the angle was smaller. 



The breadth cd of the surface cdf, figs. 4 and 5, also diminished 

 with the magnitude of the angle made by the jets ab and a/ji. 

 The angle being constant, the breadth of this surface diminished 

 with the velocity of the M^ater in the jets, 



10. When the jets encountered each other at an angle, and 



* Annates de Chimie et de Physique, 2iid series, vol. Iv. p, 280. " 



