5^» WATER BLOWING MACHINE. 



from the bottom of the channel: now this addition to the 

 height confiderably increafes the quantity of water expended 

 by the machine. 



Conclvfvms from thefe Experiments. 



Genera! cnnclu- (A.) Under the circumftances related in the firft fet of 

 fions. The experiments, 

 engine by 173 » 



cube feet fall- I. The expenditure of water for the blowing machine 



jng through 21 w ith which they were made was 173 cubic feet in a minute. 



feet, drove out J . 



441 cubic feet 2. I he air emitted from the aperture of the nozzle, being 

 of air in a ( W0 inches in diameter, when the anemometer was at 26 



minute, under a., .' , 1 • r , . 



preffureof >6 inc *hes, was 441 cubic feet in a minute. 



inches of water (B.) Of the four air-holes in the machine, three only con- 



cury; which is (C.) The hatch placed near the orifice of the machine in- 



not quite one creafed ; ts effe6l when lhe | p t f h raifed fi 



pound per fquare , » 



inch. inches one line above the bottom of the channel to which it 



was fitted. 



(D.) A crofs placed at the upper orifice of the machine 

 diminifhes its effect when the hatch is taken away: on the 

 contrary they increafe it, if the hatch be fo placed, as to be 

 five inches eight lines above the bottom of the channel, an 

 elevation greater than that mentioned in the preceding 

 paragraph (C.) and which increafes the expenditure of 

 water. 



From thefe refults it may be inferred, that the crofs mould 

 not be ufed in feveral cafes, where the quantity of water with 

 which the machine is fupplied, is confined within certain 

 limits. 



ANNOTATION. W. N. 



The water blow- The blowing engine defcribed in the preceding memoir 

 ing engine a ^ s upon tne principle of the lateral adhefion of fluids, upon 



farther explain- * r ' . 



ed. which Venturi has fo ably written, m a treatile given entire 



in our Quarto Series of this Journal, and feparately publifhed 



afterwards by Taylor in Holborn. The fliower of water in 



its defcent through the vertical pipe carries down a mafs of air 



along with it, in the fame manner as a fhower of rain on the 



flat furface of the fea produces that temporary blaft of wind, 



3 which 



