7. YORKSHIRE. 175 



vulcts laft mentioned to a height much ex- 

 ceeding that of the hills to be watered j fre- 

 quent!)' abounding with fprings almoil to 

 their higheft f>.vells. 



Thefe fprings arc collcdlcd and conducted 

 by a narrow channel down the Hope of the 

 mountain fides, and along the face of the 

 precipice, until the fummit be gained ; the 

 waters being thence conveyed to the place or 

 places defircd. 



In planning an artificial rill, a level and 

 lome little knowledge of the country are the 

 requifite guides. The furveyor begins at 

 the place to which water is required to be 

 brought-, and afcertains the loweft part of 

 the brink of the precipice from which water 

 can be conducted. The face of the preci- 

 pice is traced in like manner ; and, if necef- 

 fary, the afccnt of the moreland hills ; until 

 fprings, or their natural rills, can be com- 

 manded. 



If his level bring him to the bottom of 

 the fleep foon enough to catch the rivulet 

 which runs at its foot, the work is readily 

 completed. \i nor, he goes above its high- 

 eft bend; generally to the head or highcit pare 



of 



