Hydraulics* 3

Pistons, as in all Kinds of forcing Pumps*

&c. (5.) By the Power of Attraction, as

in the Cafe of Tides, &c. Of all whichin Order.

I. The most natural Motion of Fluidsis that arising from the Force of their ownGravity, by which those Parts which standhighest press upon others below them, tillby that Means they rife to the fame hori-zontal Level. Thus Water in a FountainA BCD by its Pressure raises that in the ^Aqueduct FGH to the fame Height IK Flg . 5 /L M, in every Direction or Position of theDuct GH or GN; unless the Orifice ofthe said Duct be below that Level, in ■vctnch.

Cafe the Water will continually flow tornthe fame. The Reason hereof is evidentfrom the Principles of Hydrostatics, whereit was shewn, that the Pressure of Fluids wasin Proportion to the Altitude only , and not ac -cording to the Quantity thereof ; and thereforethe Effect or Rife of the Fluid in the Ductmust be equal thereto. Or thus ; Fhe Velo-city of the Fluid in the DuSl at L, is to thatin the Fountain at IK, as the Quantity ofthe Fluid in the Fountain is to that in theDudl in given Altitudes ; whence (from thePrinciples of Mechanics) the Momentum ofthe Fluid in each will be equal, and con-B 2 fequently