240 THE NATURAL HISTORY 



so continues to do, be the weight of the atmosphere what 

 it may. The plate of the barometer at Newton is figured 

 as low as 27 ; 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 

 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, etc. 



LETTER LXI 



TO THE HONOURABLE DAINES BARRINGTON 



Since the weather of a district is undoubtedly part of its 

 natural history, I shall make no further apology for the 

 four following letters, which will contain many particulars 

 concerning some of the great frosts and a few respecting 

 some very hot summers, that have distinguished themselves 

 from the rest during the course of my observations. 



As the frost in January 1768 was, for the small time 

 it lasted, the most severe that we had then known for 

 many years, and was remarkably injurious to ever-greens, 

 some account of its rigour, and reason of its ravages, may 



