[ To face page 244. Phyf. C/.] 



The MEAN STATE of the ATMOSPHERE in St Peterfburg, for Sixteen Years, extraaed from a Regifter of the 

 Weather, kept by ProfefTor Euler, perpetual Secretary to the Imperial Academy of Sciences. 



For the fix Winter Months, November, December, January, February, March 

 and April, which make i8i days of the common year. 



I. B A R O 



At 20 feet above the mean level of the Neva, and at 6000 feet from its falling 

 into the Gulph of Finland. 



At highert, 28-87 commonly in January. 



At loweft, 26.99 ofteneft in November. 



Difference, 1.88 The mean between thefe ejrtremes, 27.93. 



Mean height, 28.02 Paris inches. 



It (lands 9 j days above 28 inches, and 86 days below it. 



For the fix Summer Months, Way, June, July, Auguft, September and Oflober, 

 which make 184 days of the year. 



METER. 



N. B. The fcale of the barometer is divided into Paris inches and hun- 

 dredth parts. 

 Athigheft, 2S.47 ofteneft in May or Ofliober. 



At loweft, 27.50 ofteneft in September or Oilobcr. 



Difference, .92 The mean between thefe extremes is 27.96. 



Mean height, 28.04 Paris inches. 



Its height for 107 days is above 28 inches, and for 77 days below it. 



II. THERMOMETER. 



De l'Isle's Thermometer in the Ihade, and expofed to the north, the inftrument in ufo in the Imperial Academy of Sciences. 



Greateft cold, 196° commonly in January, equal to 24° below o of Fahren- Greateft heat, 106° commonly in July or Auguft, equal to 85° of Fahr. 



HEIT, or 24°i of Reaumur below o. above o, or to 24°^ of Reaum. above o. 



Leaft cold, 141° in November or April, equal to 57° of Fahr. above o, or Leaft heat, 144° in May or Oftober, equal to 41° of Fahr. above 0, or to 



3°J of Reaum. above 0. 3° of Reaum. above o. 



Difference, 55° equal to 64° of Fahr. or 28°^ of Reaum. 



Mean cold of the night, 162° equal 23° of Fahr. above o, or equal 7° of Reaum. 



below 0. And of the afternoon, 154° equal 27° of Fahr. above o, or equal 2° 



of Reaum. below 0. 

 The cold has been above 170° for 47 nights, equal to 8° of Fahr. above o, or equal 



to io°f of Reaum. below o. And above ijo", or the freezing point, for 156 



nights. 

 The mean term of the firft froft, the 9th Oftober, new ftUe. 

 The mean term of the Neva freezing, the 27th November. 



Difference, 38° equal to 46°^ of Fahr. or equal to 2o°f of Reaum. 



Mean heat of the afternoon, 127°, equal to 59° of Fahr. above o, or equal to I2* 

 of Reaum. above o. And of the night, 136°, equal to 49° of Fahr. above 0, or 

 to 2°j of Reaum. above 0. 



The heat of the afternoon has been 130°, equal to 56° of Fahr. above o, or io°| 

 of Reaum. above ; and above 150° for 182 days : That is to fay, that the ther- 

 mometer has been fo many days above the freezing point. 



The mean term of the laft froft, 3d of May, new ftile. 



The mean term of the opening of the Neva, 19th of April. 



Perfefl; calm, 28 days. 



Briik gales, 50 days. 



N. 14 days. E. 23 days. 



N.E. 19 S. E. 12 



III. w 



Light breezes, 87 days. 



Strong gales, 16 days. 

 S. 20 days. W. 45 days. 

 S.W. 22 N.W. 26 



N D. 



Perfect calm, 

 Briflc gales, 

 N. 32 days. 

 N.E. 15 



41 days. 

 53 days. 



E. 



S. E. 



19 days. 



s. 



S.W 



Light breezes, 75 days. 



Strong gales, 15 days. 

 22 days. W. 27 days. 

 24 N.W. 27 



Sky clear. 

 Fog, 

 Rain, 

 Snow, 



IV. s 



Cloudy, 68 days. 



K Y AND 



Overcaft, 74 days. 



S P H 



39 days. 

 26 — 



20 — 



64 Mean term of the firft fnow. Oft. 9. N. S. 



Qu;:ntity of rain and melted fnow, A-^i' "f about 5 inches. 

 Aurora Borealis, 16 or 17 days. 



Tempeft, feldom. 



Hail, ' very feldom. 



53 days. 

 17 



ERE. 



Cloudy, 87 days. 



Overcaft, 44 days. 



T M O 



Sky clear. 

 Fog, 

 Rain, 



Snow, from 6 to 7 days. Mean term of the laft fnow, 4th of May, N. S. 

 Quantity of rain-water, lo^^, or about II inches. 

 - Aurora Borealis, from 8 to 9 days. 



Tempefls, from II to 12 



Hail, from 2 to 3 



