Hydraulics; *9

Whence they are supplied by proper Canalsor Springs (LXXII.) * ROli

there can be oo Times the Water of the TTjslm/w broughtto the Mediterranean by all its Rivets. (2.) oc

tor accounts for Springs by the Quantity of V apoexhaled by the Sun alone, whereas if we .^ j fhalf this Quantity, and take in what is raised byWind and Agitations of the Sea, togetherwith the largeSupplies from Rain, melted Snow, we lha un-doubtedly find sufficient Matter for the Sources ot a .the Rivers and Springs. (3.) As the Vapour is ex aefrom the Surface of the Water only, it will be pro-portional to the Heat in the Surface only, which multbe nearly the fame for the most Part of the Lay withe contiguous Air, and therefore the Case is not lo■Widely different from the Doctor’s Experiment as mightbe at first imagined.

(LXXII.) 1. The Nature of the bendedshort (of which we have made so muc “t , ■ ,

ceding Annotation) will easily appear by con £ w.follows. A B C D is a Vessel, into which is mserted at Platsthe Bottom a bended Pipe BGHIK to represent the XVIII;Syphon. Now if Water be poured into the Vessel, it Fig. L»will as it rises in the Vessel rife also into the PipeDuct, till the Water in the Vessel be upon a Level F Ewith the upper Part G of the curved Tube; what moreis poured in after this will run over the Bend at G downthe lower Part G H ; and from the lowest Point H itWill, by the fame Principle as before, be forced intotbe fifing Part H I, where at the Bend I it will againtun over, and descend through the Part IK, and at Jvit will run out, as being lower than the Level 01 theBottom of , the Vessel CL. , „

2- That the Pipe must necessarily be full to the'MiAltitude everywhere as the Watef stands ih the Vessel*by the Pressure of that in the Vessel, is evident fromWhat we have shewn in Annotation LXX. And since 1tail rise ho higher in the Vessel than in the P‘P<;> an “

the Pipe it can rise no higher than the bended art£ 2 tjr or