Royal Society. 233 



cerned. Surely the man whose investigations en optics have won 

 him such high renown is not likely to fall into the error of regarding 

 the phenomena in question as lying beyond the limits of physical 

 explanation, or of forgetting the possible influence of diffraction and 

 interference in their production. 



Grounding his views on the theory of undulation, the aim of the 

 author is to show that the corona, the coloured light, and the red 

 projections from the moon's rim during a solar eclipse, are all the 

 production of diffraction and interference : the results of his inquiry, 

 which certainly evinces considerable ingenuity and a patient study 

 of the phenomena, are as follows : — 



The corona observed from the absolute shadow of the moon owes 

 its existence to the diffraction of the sun's rays at the moon's edge. 



The coloured fringes, caused by interference, exterior to the sha- 

 dow, are the origin of the various colours observed on clouds during 

 a total eclipse, as also of the colours which precede and follow the 

 total occultation. 



The coloured light observed during the total eclipse is the light 

 reflected from the coloured atmospheric envelope which immediately 

 surrounds the absolute shadow. 



The dark, bright, and oblique-directed radiations of the corona 

 are phenomena of interference, due to diffraction by the mountains 

 on the moon's edge, when these mountains lie in or near the line 

 which connects the observer with the sun. 



If, however, these mountains are peculiarly shaped, or if they lie 

 outside the above line of connexion, the light diffracted by them 

 creates the appearance of the red projections. 



The red colour of the projections, and of the surfaces which ap- 

 pear detached from the moon's rim, and the increase and decrease 

 of the projections according to the relative position of sun, moon, 

 and observer, are due to the deportment of the light sent to the 

 observer from the aether particles in free space, when these particles, 

 through the interference of the light diffracted on the mountains at 

 the edge of the moon, are more strongly excited than the neigh- 

 bouring ones. 



XXXIV. Proceedings of Learned Societies. 



ROYAL SOCIETY. 

 [Continued from p. 152.] 

 Jan. 22, A PAPER was read, entitled, " Researches on the Geo- 

 1852. ■£*- metrical Properties of Elliptic Integrals." By the Rev. 

 James Booth, LL.D., F.R.S. &c. Received November 17, 1851. 



In this paper the author proposes to investigate the true geome- 

 trical basis of that entire class of algebraical expressions, known to 

 mathematicians as elliptic functions or integrals. He sets out by 

 ■bowing what had already been done in this department of the 

 subject by preceding geometers.. That the elliptic integral of the 

 second order represented an arc of a plane ellipse, was evident from 



