C ] 
The lecond Difcourfe jDhews by Experiment that the 
quantity of Water expended by a/^-/- £eaii of the lame Dia- 
meter of Bore, but at different hights of the refervatory, 
are in a fubduple proportion of thele hights ; and it being 
found that at the hight of 1 3 foot, a jet £ea?^ of \ of an Inch 
Diameter, evacuated 14. F^m Pints, or 14 parts of 3 5 of 
theP^m CubeFootin aMin^ute, thence is concluded the 
expence of Water at any other hight of the Relervatory 
through the fame Bore. 
The third Difcourfe fhews that the quantity evacuated 
by different Bores at the fame hight of the Refervatory, are 
as the Squares of the Dianieters of the Bores, the which is 
proved both Mathematically and Experimentally : The 
fourth Difeourfe flievi's the manner of finding the quantity 
of Water which a River or an A({mduB furnifhes, which is 
illuftrated by the Example of the Seine at Varis, 
The fourth Part Treats of the height to which the 
Water of Fountains rifes, and its firfl- Difcourfe, fliews 
that the jech d'^ea^^ never rife fo high as theil' P^efervatories, 
but allways fall fliort thereof, by fpaces which are in du- 
plicate Proportion of the heights they rife to^ which is pro- 
ved by feverai Experiments : The next thing inquired after is 
the beft fort of Ajutages or Ipouts for jets £em^ affirming 
from Experiment, that an even poIilLed round hole in the 
end of the Pipe, gives a higher jelt than either a Cylindrick 
ox Conic d Ajutage^ of which yet the latter is the better, 
Laftly^tis made out, that very great heights of Refervato- 
ry are altogether ufelefs, the Water being by its great Veloci- 
ty difperfed into fmall drops and its force ioft, fo that the 
height of thtjecf is not proportionably encreafed : A fexond 
Difcourfe of this Part handles the Amplitudes or Diftan- 
ces Oblique jecis, according to the Doftrine of Galileo and 
Ton ice Hi J and concludes with a Geometrical way of find- 
ing the iieight of the Refervatory by the Horizontal Stream 
ilTuing out of a Hole bored in the fide of the Pipe* 
The., 
