The Natural History of Selborne 367 



this house : but if the rule holds good, which says that mercury in a 

 barometer sinks one-tenth of an inch for every hundred feet eleva- 

 tion, then the Newton barometer, by standing three-tenths lower than 

 that of Selborne, proves that Newton House must be three hundred 

 feet higher than that in which I am writing, instead of two hundred. 

 It may not be impertinent to add, that the barometers at Selborne 

 stand three-tenths of an inch lower than the barometers at South 

 Lambeth : whence we may conclude that the former place is about 

 three hundred feet higher than the latter; and with good reason, 

 because the streams that rise with us run into the Thames at Wey- 

 bridge, and so to London. Of course, therefore, there must be lower 

 ground all the way from Selborne to South Lambeth ; the distance 

 between which, all the windings and indentings of the streams con- 

 sidered, cannot be less than an hundred miles. 



I am, &c. 



