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APPENDIX. 



LESSON 42. 



Table of the distances, rotations, periods, &c. of the 

 Sun and Planets. 



Note. The planets receive light and heat from the sun 

 according to the square of their distances, that is, light and 

 heat decrease as the jgquare of the distance increases. If the 

 distance of one planet be called 1, of another 2, and of a third 

 3, the heat and light received at the first is 1x1=1, at the 

 second 3x2=:4 times less, or i, at the third 3x3=9 times 



