^ Prof. Magnus's Hydraulic Researches. 



oil tlie contrary^ a larger cross section common to both, the incli- 

 nation of the several surfaces towards each other changed, so that 

 the first surface formed an angle with the one which w^as parallel 

 to the jets ab and 0^, before they encountered each other. This 

 angle increased with the magnitude of the common section, and 

 amounted to 90° when the latter was as great as possible, that 

 is, when the encounter was a central one. 



The second water surface ed,f made with the first, and the 

 third with the second, almost the same angle as the first surface 

 bcdci made with the plane parallel to the two jets. The second 

 surface edif, therefore, made with a plane parallel to the jets ab 

 and afii, an angle equal to double that which bcc,d made there- 

 with; and if a third surface existed, it made an angle with a 

 plane parallel to the jets of three times the above magnitude. 



14. When, before contact, the axes of both jets were in one 

 plane, in other words, when the jets made a central encounter, 

 the first surface bccid, as already mentioned, made an angle of 

 90° with the plane of the jets abai; the second water surface was 

 parallel to the plane of the jets, and the third again at right 

 angles thereto. These positions of the surfaces, however, were 

 only \isible when the velocity with which both jets met was rather 

 small ; in the latter case, however, the surfaces could be very 

 distinctly seen turned at right angles to each other. Fig. 9 

 represents such a phsenomenon as seen from one side and from 

 above. 



Explanations of the phanomena observable when Jets of equal 

 diameters meet each other-. 



15. Before proceeding to describe other experiments, it will 

 be best to give an explanation of those already described. 



When two fixed bodies, for instance two perfectly equal spheres 

 moving towards each other in tlie same right line with equal 

 velocity, strike one another, they remain at rest provided they 

 are inelastic ; and when two more equal spheres follow the first 

 two, they strike those already at rest with equal but opposite 

 forces, and consequently are themselves also brought to rest. 

 The deportment of liquid masses is difi"erent from this. When 

 two perfectly equal water-jets, each of which may be considered 

 as a series of particles of water following each other, move in 

 opposite directions against each other so that their axes lie in 

 the same right line, the first particles which strike one another 

 are pressed against by those which follow, and in consequence 

 of this pressure the water moves sidewards. As this action is 

 continually renewed, a continuous lateral motion from the place 

 of contact is sustained, and with equal velocity in all directions. 



