The Natural History of Se I borne 383 



weight of the atmosphere what it may. The plate of the baro- 

 meter at Newton is figured as low as 2 7 ; because in stormy 

 weather the mercury there will sometimes descend below 28. 

 We have supposed Newton House to stand two hundred feet 

 higher than 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 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 baro- 

 meters 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. 



