24

Hydraulics.

merit a or Forces pf several Jets spouting-through the Sides or Bottoms of Vessels at

different

the Jet a little, that the upper Water may not bearupon the rising Stream, for the Jet will then play higher*but be less beautiful.

7. If the Hole of the Adjutage G be less than I ofan Inch in Diameter, the Force of the Attraction ofCohesion will extend itself through the Body of the Jetat the Hole, and greatly obstruct its Ascent; hencethe Rise of Jets in Models for Experiments cannot beexpected so high as others, because of the very smallHoles made use of in them. Whence all Jets of largerFountains (such as are in Gentlemens Gardens) oughtto exceed' J of an Inch in Diameter, and that in Pro-portion to the Height of the Reservoir, as will be shewnhereafter.

8. If the Conduct-Pipe E F G be not of a properSize to supply Water, as fast as it can be expended atthe Adjutage G, the Jet will likewise be checked, andwilbwiot rise to the full Height. To ascertain theProportion of the Conduct-Pipe to the Bore of theAdjutage, is the Business of Experiments; and whathas resulted from thence, in regard to this Matter, willbe shewn in a Table by and by.

9. And one Thing more is necessary to be known,that the Jet may play the highest possible, viz. that thePart of the Conduct-Pipe at the Adjutage does ■ notturn up at a Right Angle, but with a gentle easyCurve ; that is, not as at G, but as at L, where theJet plays to a greater sleight at K. The upright Partat G directly resists the Water coming from F, wherethe Curve at L causes the Impulse of the Water againstit to be very oblique; and therefore a less Part of itsMomentum will be destroyed, and consequently, thegreater remaining Force will throw the Jet the higher.

10. From what has been said in Art. 4. it appears(cisteris paribus) the Hole.in the Adjutage ought to bemade in a thin Plate of Brass, and not through theBore .of a Tube of any Length, because of the Quan-tity