Hydraulic s.
the Weather again alters to wet, and the Spi ing ceasesof course, till it meets a fresti Supply from the preceding
Rains, and so on.
2,0. The Intermitting Springs may be thusaccounted for : Let I KL be a Cavity in the Mountain,to which at I there is a feeding Stream that brings theWater from other Parts, and at K, on the lower Part,there goes a Duct K k C, which is of a curved orcrooked Form, and conveys the Water to the Side ofthe Hill at C, where it breaks out in a Spring. Heretis evident, that as the Water rises in the Cavern, itWll rife in the Duct at the fame Time, till the Surfaceof the Water IL be level with the highest Part k ofthe Duct, aster which the Water will descend from kto C, which Point C, being lower than the Orifice ofthe Duct K, will exhaust the Cavern of all its W r ater,and then the Spring will stop till the feeding Stream Ireplenishes the Cistern to the fame Level I K, and thenthe Fountain will play again ; this supposes the DuctRC to carry eft' more Water than the other at I bringsto the Cistern ; and then every Thing follows from tbteNature of the bended Syphon as explained m the next
•Annotation. _ ,
2i. The Reciprocating Springs are occahoned
after this Manner. Let M N O be a Cavity supplied ,by a feeding Stream P M, and also by a Syphon K. k O,which brings Water from another Cavity above, asI K L ; the Duct ND carries the Water to the Sideof the Hill at D, and there makes a constant. Spring,W Virtue of a constant Supply of Water, by the Draink M. The Water at D will also flow and ebb alter-nately, for when the Syphon K k O works, the Surfaceof the Water MO will be suddenly raised, and pressupon the Water at N with a greater Force, by whichMeans it will issue out at D with a greater Velocity,and raise the Surface if confin’d; but when the Syphonintermits, or.ceafes, the Adamentum of the W ater at Dis not so great as before, and then the Spring will stnk
17
or dccFE«ii'&
LL. In like Manner we account, for the 1 ising of ' fj£)
ter in Wells. Thus suppose a Well be sunk at h~ ^Foot of the Hill at E, to such a Depth E V, « ^
/
st
Vol, II.