iriM New Syphon for raifing WaUr. 



refervolr beneatli, which is open, and filled with water ; and there is a valve opening 

 upwards at the lower end of each of thefe tubes. The air within is of tlie fame denfity 

 and temperature as that VTidiout ; but the external communication of this included air i* 

 prevented by the fides of the engine and the water which occupies part of its 

 interior. 



The great afpirator, the fmall afpirators, and the refervoirs, placed beneath thcfe laft, 

 have all the form of vertical prifms ; the fmall afpirators are equal and fimilar, and the 

 portions of ttibe comprized between the afpirators and their refervoirs are of equal length. 



Things being in this fituation, we are to fuppofc that the water of the great afpirator 

 flows out by the onhccf, and it is required, i. what will be the depreffion of the M'ater 

 when the fpring of the included air, and the charge of the water on the orifice of 

 emiflicJn, fliall be equal to the weight of the atmofphetc } 2. die q^iantity of water which, 

 at this period, fliall have rifen in the fmall afpirators ; 3. the requifite dimenfions of the 

 apparatus, in order that the water emitted from the great afpirator, plus that raifed in one 

 ef the other afpirators may be a determinate part of the water which a fpring of known 

 produdl affords in a day ; and, 4. the proportions of the fame apparatus which (hall give 

 the greateft ratio between the fum of the volumes raifed in all the fmall afpirators, mul- 

 tiplied by their elevatiotj, and the volume of water emitted from the great afpirator, 

 multiplied by its height. 



Fornwltc for the Solution of the foregoing Problem. 



Let Qj= the volume of water afforded by the fpring in one day. 



7 = the number of times which this volume of water contains that which flows from 

 the great afpirator from the inftant of its being filled to the cefl'ation of its efflux. 



c =: the height of the great afpirator. 



A =: the common length of the portion of pipe comprized between a fmall afpirator and 

 the refetvoir, whence its water is drawn. 



n =: the number of fmall afpirators. 



s = the horizontal feftion of each fmall afpirator. 



I =.the horizontal feiTtion of the lower refervoir, from which the fmall afpirator 

 draws the water. 



S = the horizontal fe£tion of the great refervoir. 



V = the capacity of the interior parts of the machine, which are at no time occupied by 

 water, but conftantly hold air. 



A — the height of the column of water which meafures the total prefTure of the 

 atmofpherc. 



* =: height of the water above the orifice of emifllon of the great afpirator, at the 

 moment when the fpring of dilated air within, and the charge of water on the orifice of 

 emiffion, are equal to the weight of the atmofphere. 



ji. — the correfpondent depreffion of the upper fiirface o£ the water in the great afpirator. 



