1813.] 



Neiu Hydraulic Machines, 



185 



fountain of Hiero. It is well known that this fountain of Hiero 

 is composed of two close compartments^ placed the one above 

 • the other, and separated by a diaphragm. By introducing water 

 into the inferior compartment, by means of a pipe from the 

 reservoir, the air wliose place it occupies is gradually compressed. 

 It is compressed likewise in the superior compartment, in con- 

 sequence of a tube of communication established between the 

 two compartments. The water in the superior compartment 

 being thus pressed upon, rushes through a pipe, and ascends 

 above the reservoir. 



But this effect, being produced only by the compression of the 

 air in consequence of the introduction of water into the lower 

 compartment, ceases as soon as this compartment is filled with 

 water, because then the air ceases to be compressed in the upper 

 compartment. To renew the effect we must empty the lower 

 compartment of the whole of its water. This is what M. 

 Mannoury accomplishes by means of his intermitting syphon* 

 This syphon being fitted to the inferior compartment, empties it 

 at once, as soon as the water reaches the top of the syphon. Air 

 rushes in, and supplies its place, and things arc brought back to 

 the situation in which they were before the machine began to 

 play. The jet is again renewed by the falling of the water, and 

 thus the machine continues to raise water above the level of the 

 reservoir without having any moveable part whatever. We have 

 only to repeat this mechanism by a suite of similar fountains 

 placed in stages below one another, to raise v/ater to any height 

 we please by means of a loss proportional to what runs through 

 the intermitting syphons. This is what M. Mannoury does in 

 one of his machines, which is nothing but a collection of various 

 fountains of compression, connected with each other, and so 

 contrived that all are brought into action by means of one inter- 

 mitting syphon adapted to the inferior compartment of the lowest 

 of the fountains. 



It is easy to see that the intermitting syphon may be applied 

 likewise to various other machines to restore their energy after 

 they have produced a given efiect, and thus to enable them to 

 continue their action. M. Mannoury varies his applications; 

 but the example which we have given is sufficient for explaining 

 the way in which this first mode of raising water above the 

 reservoir may be applied to machines without any moveable 

 parts. 



HYDREOLE. 



The author has giv^en the name of hydreole (composed of 

 vo'^^^ water, and A;oAo^, ^Eoius) to the mach.ines in which he 

 ernploys a mixture of water and air to make the first of these 

 fluids ascend above its natural level. This method consists in 



