NATURAL HISTORY OF SELBORNE 187 



if the rule holds good, which says that mercury in a 

 barometer sinks one-tenth of an inch for every hundred 

 feet elevation, 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 Weybridge, 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 considered, cannot be less than an hundred 

 miles. I am, &c. 



