7. YORKSHIRE. 149 



I. The Run. A bare firm I'lirfacc, as a 

 road, collefts the greateft quantity of water. 

 A grajjy furface retains the rain-water which 

 falls upon it, and which in Ic'jei iitiiatlons is 

 conduded into the foil by w'orm-holes and 

 other inlets, with which grafsland in general 

 abounds j efpecially in fummer, when a col- 

 le(5lion is of the greateft value. However, 

 if the fublbil be retentive, ditches, efpecially 

 of arable inclofures, will frequently afford 4 

 fupply even in fummer ; but, in an upland 

 SITUATION, where the fubfoil is generally ab- 

 forbent, a road, or an artificial run, becomes 

 neceffary. 



In highland Diftrids, as the Wolds of 

 Yorkfliirc, and the Downs of Surrey and 

 Kent, the furface is generally broken into 

 hill and dale, and diverfined by fmaller val- 

 lies and inequalities. In fituations of this 

 kind ARTIFICIAL RUNS atc mod wanted, and 

 may be moft eafily made. I have feen fome 

 faint attempts at making them on the Wolds 

 of this Diftrid:, by cutting a few grips with a 

 fpade above the rcfervoir ; but they were too 

 few, too fliort, and too feldom fcoured to an- 

 fwcr in ^ny confiderable degree the in- 

 L 3 tenacd 



