The Earth considered as a Planet. 69 



earth turns round upon its own axis in 

 24 hours. 



The turning of the earth upon its own 

 axis every 24 hours, whilst it moves 

 round the sun in a year, we may conceive 

 by the running of a howl on a bowling 

 green ; in which not only the center of 

 the bowl hath a progressive motion on the 

 green ; but the bowl in its going forward, 

 from one part of the green to another, 

 turns round about its own axis. 



The turning of the earth on its axis, 

 makes the difference of day and night ; it 

 being day in those parts of the earth, 

 which are turned towards the sun ; and 

 night in those parts which are in the 

 shade, or turned from the sun. 



The annual revolution of the earth in 

 the ecliptic, is the cause of the different 

 seasons, and of the several lengths of days 

 and nights, in every part of the world, in 

 the course of the year. 



But before we enter upon the more 

 particular illustration of the diurnal and 

 annual motions of the earth, together 

 with the different lengths of days and 

 nights, and all the beautiful variety of 

 seasons, depending on those motions, it 

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