SECT, xxvr.] STABILITY OF CLIMATE. 299 



cording to Sir Edward Parry, was 55 below the zero of 

 Fahrenheit's thermometer, only 3 above the temperature of 

 the ethereal regions, yet the summer heat in these high 

 latitudes is insupportable. 



Observations tend to prove that all the climates of the 

 earth are stable, and that their vicissitudes are only periods 

 or oscillations of more or less extent, which vanish in the 

 mean annual temperature of a sufficient number of years. 

 This constancy of the mean annual temperature of the 

 different places on the surface of the globe shows that the 

 same quantity of heat, which is annually received by the 

 earth, is annually radiated into space. Nevertheless, a 

 variety of causes may disturb the climate of a place ; culti- 

 vation may make it warmer ; but it is at the expense of 

 some other place, which becomes colder in the same propor- 

 tion. There may be a succession of cold summers and mild 

 winters, but in some other country the contrary takes place 

 to effect the compensation ; wind, rain, snow, fog, and the 

 other meteoric phenomena, are the ministers employed to 

 accomplish the changes. The distribution of heat may vary 

 with a variety of circumstances ; but the absolute quantity 

 lost and gained by the whole earth in the course of a year 

 is invariably the same. 



