From this account it is evident that at the time when the " gleam 

 of iight" first appeared, the edge of the Moon's disc (making no al- 

 lowance for the inequalities of her surface.) must have projected 

 several seconds of a degree beyond that of the Sun; and, as the 



ring must necessarily have been uncommonly bro^d ; a consid- 

 erable portion of the Sun mu^t, therefore, at tliat time have been 

 uneclipsed, and the quantity of light very considerable.* 



Le Monnier, (the French Astronomer Royal,) iMr. Short, 

 F. R. S. and the Earl of Morton, observed the eclipse of Julv 2oth, 

 1748, N. S. at Aberdour castle, (belonging to the Evs]]) near 

 Edinburgh. In Mr. Short's account of their observations, it is 

 stated, that 



"The eclipse was so nearly annular, that at tiie nearest ap- 

 proach the cusps seemed to want about onc-sevcnih of the moon's 

 circumference to he joined: yet a brown light was j)lainhj observed 

 to proceed or stretch along the circumference of the moon, from 

 each of the cusps, about one-third of the whole distance of tht 

 cusps from each cusp, and there remained about one-third of tht 

 whole distance of the cusps not enlightened by this brown light ;J0 

 that they were for some time in suspense whether they were to 

 have the eclipse annular." 



In a subsequent part of the same account, it is mentioned, that 

 " Mr. Le Monnier measured with the micrometer,'* attached to 



sured also the _ ^ ^ 



which he found = 31' 40"." f 



If the result last mentioned be corrected for refraction, and from 

 one half the remainder 3" be subtracted tor irradiation, it will be 

 found, by a process of computation which need not here be de- 

 tailed, that the distance from the nearest limb of the Sun, cf either 

 point of the Moon's limb, at which the "brown light" ceased to 

 be visible, (measured in the direction of the radius of the Sun's 

 disc which, produced, would pass through that point,) was 4"8S5, 

 the sun and moon be ing supposed to be perfect spheres. 



' The Sun' 



Moon's horizonta: 



. (abridged,) vol. ii. p. 591, 



