CLIMAtE of RUSSIJ. 



219 



are fet down in this reglfter ; for we have often, for example, a 

 ipore confiderable degree of cold than what is indicated abuve, 

 as our greateft during the feafon j 27° of Reaum. or 62° of 

 Fahr. below o, are often felt here, andfometimes as far as 30°; 

 nay, a cold of 32° below the freezing point of Reaum. is upon 

 record, which is the freezing point of the pureft mercury, ac- 

 cording to my experiments, publiflied here in 1785. 



It muft be alfo remarked, that the thermometer fometimes 

 has a furprifing range during winter, fo as to produce a change 

 of temperature from 10° to 25° of Reaum. (or from 23° to 

 57° of Fahr.) in 24 hours ; a trying circumftance fcr delicate 

 conftitutions, and which the moft robuft feel after the prime of 

 life. The prefTure of the air on the body is alfo equally vari- 

 able in 24 hours, as indicated by the barometer on thefe occa- 

 fions. 



BAROMETER. 



Placed 20 feet above the mean level of the Neva, and at 6000 

 from its opening into the gulph of Finland. 



Higheft, 28.87 ofteneft in January. 

 Loweft, 26.99 ofteneft in November. 



Difference, 1.88 



Mean height, 28.02 Paris inches. 



Windsi ' 



The prevailing wind during winter is the weft, and its pro- 

 portion to the eaft is, 



Weft, 1 1 3 days in the fix winter months. 

 Eaft, 68 days in the fame period. 

 N.B. The fouth wind, and all to the weft of the meridian, 

 is reckoned weft ; the north wind, and all to the eaft of the 

 meridian, is reckoned eaft. 



e e 2 This 



