Theory of the Pneumatic Parador. 303 
The oe is the experiment, of Venturi, cited i in proof of it it. 
Fig. 2. 
aaa 
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To an orifice near the bottom of a reservoir, in which water 
was maintained at the constant height of 31.5 inches above the 
centre of the orifice, he adapted the tube KLV, one inch anda 
half in diameter, and four inches and three quarters in length. 
Into the tube KLV was inserted the glass tube QRS, at the dis- 
tance of two thirds of -an inch from the orifice KL. The lower 
end was plunged in colored water, contained in the vessel T. 
The efflux of water through the tube being permitted to take 
place, four cubic feet flowed out in thirty one seconds, and the 
colored water in T rose in the tube to 8, twenty four inches - 
above the surface of the waterin T. The heanale RT was short- 
so that RT was only six inches longer than RQ, and the 
colored liquid in T rose. through RS RS, and mixed with the water 
that flowed from the reservoir theongli the tube KLY, and ina 
short time the water in the vessel T’ was emptied. The same 
effect takes place when the tube KLYV is directed upwards or 
downwards. 
The true saplallition of these and kindred ape of 
Venturi, 1s found in a fact, apparently overlooked by those who 
have adduced them as proofs of the general principle, that liquids 
flowing through a horizontal cylindrical tube, exert no pressure 
against its interior surface. When water flows through a circular 
orifice in a thin plate, the jet, in consequence of “the interference 
of the particles of the fluid coming from the parts on each side of 
