164 VOYAGE FOR THE DISCOVERY 
1820. to-day, had much of that tendency to arch, which has before been described 
on one or two occasions. Two distinct arches were thus formed this morning 
one in the northern, the other in the southern hemisphere of the heavens, 
their altitude in the centre being from 20° to 45°, and joining at each end in 
the E.N.E. and W.S.W. points of the horizon. 
Sun. 9. From half-past six till eight A.M., on the 9th, a halo, with parhelia, was 
observed about the sun, similar in every respect to those described on the 
5th, Atone P.M. these phenomena re-appeared, together with several others 
of the same nature, which, with Captain Sabine’s assistance, I have endea- 
voured to delineate in the annexed figure. 
t, u, a complete horizontal circle of white light passing through the sun. 
a, a very bright and dazzling parhelion, not prismatic. 
b, c, prismatic parhelia at the intersection of a circle a, b, d, c, whose radius 
was 22|° with the horizontal circle t, u. 
x, d, v, an arch of an inverted circle, having its centre apparently about 
the zenith. This arch was very strongly tinted with the prismatic colours. 
k, e, l. an arch apparently elliptical rather than circular, e being distant 
from the sun 26° ; the part included between x and v was prismatic, the rest 
white. The space included between the two prismatic arches, x e v d was 
