TRANSACTIONS OF THE SECTIONS. 



It ■will be understood from fig. 1, whicli represents the brilliant radiation which 

 surrounds a very small image of the sun, when it is formed either by reilection 

 or refraction, or otherwise. 



M 



rig-.i. 



rig-. 6. ^r' Fig-. 3 



rig-. 2 



R' 



V a 



Fiff.y. m^' 



riff.8. ^V' 



Fie- -5. 11 V 



Pig 9. 



If we now form a spectrum of this radiant image, either by a prism or by dif- 

 fraction, we shall have the radiant spectrum shown in fig. 2, vrhore MN is the 



