II

Hydraulics.

By the Pressure of the Phiid it mayeasily be convey’d over Valleys and ^ s

z. They who advance the Capillary Hypothesis, orsuppose the Waters rife from the Depths o t e athrough the porous Parts of the Earth, as it ri es mCapillary Tubes, or Tubes of Sand or Aftes, seemnot to consider one principal Property of this Kind otTube, or this Sort of Attraction ; for though the Wa-ter rise to the Top of the Tube or Sand, jet will itrise no higher, because it is ,hy the Attraction o eParts above that the Fluid rises, and where t a iswanting it can rise no farther. Therefore, tho theWaters of the Sea may be drawn into the Substance othe Earth by Attraction, yet can it never be railed bythis means into a Cistern or Cavity to become the source

of Fountains. , , c

4. The true Principles which supply the Waters of

Fountains or Springs, are undoubtedlyRain-Water , and condensed V^p ourS * eve t . 1 .

tempted to solve the Phenomena by Snow or Rain only ,but others making an Estimate of the Quantity orand Snow, that falls in the Space of a Year, to fee ifit would be equal to that which the Rivers dischargeannually into the Sea, found that it was much fcort of

that Quantity. , ,

5. But that which was most extraordinary was, iathey found by their Experiments, that the Rain anSnow which fell in one Year would not produce morethan | of what was raised in Vapour; for by Experi-ment it was found, that the Rain and Snow that sell ina cylindric Vessel, raised a Column of Water about 19Inches higst; whereas the Water raised in Vapour wasyearly about 32 Inches in Altitude. This great De-ficiency of 13 Inches plainly indicated another Way,by which the Waters circulated from and to the Sea.

6. This (among many other Things) was left to t eDiscovery of that sagacious Naturalist Dr. Halley, w 0being on the Tops of the Mountains in the Isle of t.Helena (in South Lat. 16°) making his Observations