16 Prof. Magnus on the Motion of Fluids. 



made by fixing the point out of the central line of a jet which 

 issued through an orifice 5 millims. in diameter ; sometimes so 

 that the point was 1*75 millim. distant from the centre when 

 the jet was projected through the air, and sometimes at a distance 

 of from 2-5 to 3 millims. therefrom. Even with this position of 

 the point the force of the jet entering the salt solution was suffi- 

 cient to carry the fluid up the tube and through cd as before. 



The results of these experiments will be found in the following 

 table : — 



From this it appears that the quantity of the salt solution in- 

 creases considerably when the point deviates from the centre of 

 the jet. 



35. I shall now apply myself to the explanation of these phse- 

 uomena. Unhappily in the present state of science a strict 

 mathematical treatment of the question is not possible. I believe, 

 however, the following considerations will furnish a complete 

 explanation of the action observed. 



Suppose a fluid to enter another of a similar nature contained 

 in a vessel of unlimited size, through an orifice situate at a suffi- 

 cient depth beneath the surface. The jet thus entering widens 

 continually, that is to say, its cross section becomes greatei', while 

 its velocity decreases as the distance from the orifice increases. 

 Both these results are easily observed. 



If the same quantity of water passed through every cross 

 section of the, jet in the same space of time, then each succeeding 

 mass would be just sufficient to take up the space occupied by 

 the preceding. 



We will now inquire under what conditions this is possible. 

 To this end let us fix our attention on a definite mass of fluid, 

 say the quantity which enters through the orifice during the 



* The diameter of the orifice through wliich the jet entered the salt so- 

 lution was 5 millims. 



