1813.] 



New Hydraulic Machines. 



189 



syphon^ that is to say, in the bending of the syphon where it is 

 horizontal^ this portion of fluid being animated with no living 

 Jbrcey either actual or potential, the sum of the living forces of 

 the whole mass would not be altered, but it will be distributed 

 through a smaller mass. 



Suppose we continue to pour water into the first branch of the 

 syphon : this new quantity of fluid will bring a new sum of living 

 forces to the mass. If then at each oscillation we were to 

 remove a portion of inactive fluid, while on the other hand we 

 introduce a new change of living forces, the sum total of the 

 living forces would continually increase, though the total mass 

 remained the same. Hence the ascent of the water in the 

 second branch of the syphon would increase indefinitely. 



But if we wish to set limits to this increase of the living force 

 of the column, we have only to cut off the second branch of the 

 syphon at any height we think proper, then at each oscillation a 

 portion of fluid will flow from the end of that branch, and thus 

 the water will be made to rise higher than the reservoir. 



The difficulty then is reduced to abstract the competent 

 portion of fluid which fills the lower part of the syphon the 

 moment the fluid becomes stationary, and this without employing 

 valves or any moveable piece of machinery whatever. This M. 

 Mannoury accomplishes in a very simple manner, by establish- 

 ing, at the lower part of the syphon, a small solution of conti- 

 nuity between the two branches of the same syphon. 



When the water is animated by a rapid mov^ement of oscilla- 

 tion it cannot escape through that opening, because its acquired 

 motion enables it to clear the small interval ; but the moment 

 it becomes stationary, the acquired motion having now no place, 

 the portion of fluid, which corresponds to the small opening, 

 escapes ; and this is precisely what must happen in order that the 

 machine may be able to produce its effect, without any loss of 

 living forces, as we have explained above. 



Still more certainly to prevent the escape of water, before it 

 has acquired a state of rest, M. Mannoury makes the lower end 

 of the first branch of his syphon terminate in a truncated cone, 

 which occasions a contraction in the fluid vein that issues out of 

 it, and determines it to enter entirely the second branch. 



It is much easier to explain than to foresee this singular effect; 

 but success has justified this delicate experiment of M. Man- 

 noury. it is obvious that much time and many trials are neces- 

 sary to produce from this principle an useful machine. At 

 present we can only consider it as a very curious experiment, 



M. Mannoury wished to know what would happen when the 

 second branch of the ^-yphon was shut at its upper extremity by 

 means of a. plate, h -v^^ g Moly a small opening in tliat plate. 

 What happened was us tbliows. The column of waler, which 

 mounts by its bsciilutious iu the second bxaach of the syphon. 



