300 OUTLINES OF NATURAL PHILOSOPHY. 



portion of the globe contained between the parallels 

 of Stockholm and of the Cape of Good Hope, and 

 between the meridians of Stockholm and Mexico. 

 This does not seem quite exact ; no part of North 

 America having its mean temperature the same with 

 that of places of the same latitude in Europe. It 

 would require at least 10 to be taken from M, to 

 adapt the formula of the last article to the New Con- 

 tinent. See KIR WAN'S Estimate of the temperature 

 of different Latitudes^ p. 15. 



409- As we go eastward from the shores of the 

 Atlantic, the mean temperature of any parallel be- 

 comes lower, at a rate that may perhaps, for the 

 north part of the temperate zone, be estimated at a 

 degree for 150 miles. 



At St Petersburgh, lat. 59 56', about 750 miles' from 

 what may be accounted the shores of the Atlantic, 

 the temperature is 5 5' below the standard. The 

 medium temperature of January is no more than 

 10. By computation from the formula above, it 

 ought to be greater than 3. The winter lasts from 

 October to April, and the cold is sometimes as great 

 as the freezing point of mercury, or 39 From 

 a mean of several years, the mean of the winter cold 

 is 25. KIRWAN, ibid. p. 61. 



It was at Krasnojark, lat. 56 30', long. 93 E. that 

 mercury was first known to freeze by natural 

 cold. 



If 



