WEATHER. 315 



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 baro- 

 meters 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 a hundred miles. 



LETTER CV. 



TO THE SAME. 



SINCE the weather of a district is undoubtedly part 

 of its natural history, I shall make no farther 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 



