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formed, the lower limb of which was beautifully defined. 
The remarkable feature in this phenomenon was the intense 
blackness of the sky beneath the arch, as contrasted with 
that exterior to it. The darkness of this space was such, 
as to resemble a dense cloud, fringed by the auroral light ; 
and the doubt was suggested, whether the dark cloud noticed 
by many observers, in connexion with aurora, may not have 
been an appearance of the same kind, though less regular in its 
outline. In the aurora of the 19th, the blackness of the 
space enclosed by the arch was certainly not due to the 
presence of a cloud, for the stars were distinctly visible in it. 
Mr. Lloyd stated, that he was so much interested in this 
part of the phenomenon, as to lose the opportunity of ob- 
taining a measure of the altitude of the arch. 
Soon after 10 o’clock, the arch began to break up into 
streamers. Its appearance at this period was such as is 
represented in the subjoined sketch. 
From this time, until half past eleven o'clock, Mr. Lloyd 
took no notes of the appearances, having been engaged in 
2 
