Singular Rainbow. 545 
A B was a perfect and very splendid primary bow. cD re- 
presents a secondary bow, having its colours of course in an 
inverse order to those of the primary. But from £, in the 
direction £ F, came the segment of a third bow, commencing, 
as nearly as could be guessed, between 15° and 20° from the 
vertex of the secondary, and descending in the direction shown 
in the figure. This segment was equally vivid with the second- 
ary, but had its colours in the order of the primary. No con- 
tinuation of it could be discerned above or on the left of the 
secondary, and its centre evidently lay considerably to the left 
of that of the other bows. The termination at the lower ex- 
tremity (F) was abrupt and well defined. It remained visible 
for more than ten minutes; the extremity (F) appearing lat- 
terly to have moved somewhat nearer to the primary bow, 
from which, however, it was never less than a bow’s breadth 
distant. The side c of the upper bow first became invisible, 
but so long as the other side could be seen the segment could 
also. 
A somewhat similar phenomenon is recorded in the Phzl. 
Trans. p. 1793., as having been seen on the coast of Hamp- 
shire; and the explanation there offered is, that the additional 
bow was caused by the reflection of the sun from the sea when 
perfectly still. But, if this were the cause, would not such 
appearances be more usual? Besides, if a ray of light pro- 
134 ceeding from the earth falls on 
the lower side of a drop, must 
it not be refracted into the air 
(as in fg. 314.), and not towards 
the earth, s being considered 
the reflection of the sun? And 
what again becomes of the received opinion, that the eye of 
the observer must be in the apex of the cone, of which the 
bow forms the base ? 
SS 
I am, Sir, &c. 
Coventry, Oct. 12. 1829. E.G. 
