ASTRONOMY. 



96. On comparing the sun's diameter, mea- 

 sured from time to time, with his place obser- 

 ved in the ecliptic, it is found, that if the sun's 

 mean apparent diameter be m, his least diame- 

 ter m ??, and z 9 his angular distance* at any 

 time from the point in the ecliptic where his 

 diameter is least, his apparent diameter at that 

 time is m n. cos z. 



" w = 32' 06".2, and m n = 31 ' 32".8, so that 

 n = 32".4, and mini: 19262 : 324, or as 59.45 

 to 1. 



The sun's apparent semidiameter is therefore always 

 expressed by the formula (32' 6".2) 32".4 X 



cos z = 32' 6".2 (1 J cos a). 



Off f d 



Because the distance of the sun and earth must be in- 

 versely as the apparent diameter of the sun, there- 



T> 



fore, if that distance be called y 9 y~ 



m(l - cos z) 

 m 



where B is a constant but indeterminate quantity. 

 Now, if a be assumed for the mean distance of the 



n 2 " \ 

 sun, and if B = m a (1 ), j/= - 



I cos z 



m 



an 



