A HISTORY OF SCIENCE 



in the hemisphere of darkness there would be found a 

 region of extreme cold and perfect dryness. 



" Let us now suppose the earth as turning on its axis 

 in the equinoctial situation. The torrid region would 

 thus be changed into a zone, in which there would be 

 night and day; consequently, here would be much 

 temperance, compared with the torrid region now 

 considered ; . and here perhaps there would be formed 

 periodical condensation and evaporation of humidity, 

 corresponding to the seasons of night and day. As tem- 

 perance would thus be introduced into the region of 

 torrid extremity, so would the effect of this change be 

 felt over all the globe, every part of which would now 

 be illuminated, consequently heated in some degree. 

 Thus we would have a line of great heat and evapora- 

 tion, graduating each way into a point of great cold 

 and congelation. Between these two extremes of heat 

 and cold there would be found in each hemisphere a 

 region of much temperance, in relation to heat, but of 

 much humidity in the atmosphere, perhaps of continual 

 rain and condensation. 



" The supposition now formed must appear extreme- 

 ly unfit for making this globe a habitable world in 

 every part; but having thus seen the effect of night 

 and day in temperating the effects of heat and cold in 

 every place, we are now prepared to contemplate the 

 effects of supposing this globe to revolve around the 

 sun with a certain inclination of its axis. By this 

 beautiful contrivance, that comparatively uninhabited 

 globe is now divided into two hemispheres, each of 

 which is thus provided with a summer and a winter 

 season. But our present view is limited to the evap- 



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