158 on philosophical geography. Feb. l . 



ttal rotation of the globe, and produce their sensible 

 effects by the changes that take place between the day 

 and the night, wh^ re is, in polar regions, the great 

 vicifsitudes of heat and cold are occasioned by the 

 earth's annual revolution, and produce their sensible 

 effects by the changes that take place between the j-«;«- 

 tner and the suiter. Hence again it follows, that if 

 the heat of the sun were the only cause of the varia- 

 tion of winds, the changes, if any, that were pro- 

 duced by that means, in equatorial regions, ought to 

 be diurnal only, whereas the vicifsitudes at the pole 

 fhould be only experienced once in six months- 



And, as these deviations of climate and seasons are 

 gradual from the equator to the poles, it must happen 

 that as you approach to, or recede from either 

 the one or the other of these vicifsitudes will be 

 more or lefs experienced. But at the equator, the 

 influence of the sun is more powerful, upon the whole, 

 than at the pole. The effects of the sun, therefore, 

 in altering the wind, must be much lefs interrupted by 

 lefser causes, and therefore more steady in equatorial 

 than in polar regions, and consequently must be much 

 more stricking to the senses. 



Experience, in this instance, accords exactly with 

 oiir reasoning. Variable winds do, in general, pre- 

 vail towards the poles, and constant winds towards the 

 equator. But, in summer, the continual heat, even 

 in high latitudes, comes to be sensibly felt, and pro- 

 duces changes on the wind that are distinctly per- 

 ceptible. In our own cold region, the effects of the 

 sun on the winds are sensibly felt during summer and 

 autumn, though much inferior in degree to that in 



