XXVIII 



INTRODUCTION. 



E F G at 3 h 30 m ; the apices C and G are carried a little above the more condensed portion of 

 the ring ; but the reader is at liberty to suppose them to be at any other part, as he may think 

 best. The direction of the sun is given; and S', S", S'", S"", S""', are supposed to be rays of 

 light proceeding from that luminary. 



NEBULOUS RING, WITH THE EAKTH FOE ITS CENTRE. 



In this diagram, the sun's rays being S', S", &c., B 0, F 0, &c., will be the reflected rays; 

 and the several angles between these lines of incidence and reflection, together with the num- 

 ber of rays reflected to the eye, out of every 1,000 incident rays, according to Bouguer, are in 

 the following table : 



