128 
REFRACTION. 
heat. The whole intervening atmosphere was dis- 
turbed and flickering. 
"Upon looking- at this curious spectacle through our 
best Fraiinhofer glass, the clearly defined edges of a 
number of large icebergs could be seen, borne by re- 
fraction into the air, duplicated by inversion, and pre- 
serving that vertical parallelism of sides before alluded 
to as characteristic of the refracted berg. From the 
lower face of their inverted images were exhaling — • 
if I may use the word — those wonderful clouds of ap- 
parent smoke. Here, too, at an altitude which, judg- 
ing by the bases of the bergs, corresponded to the re- 
fracted or secondary horizon, a lateral distortion sent 
out huge tongues, like projecting rafters, which, when 
not obscured by the ' smoke,' contrasted black against 
the sky. All this was so combined with architectur- 
al forms, that it was hard to avoid the impression of 
some mighty city in conflagration." 
During all these phenomena, the position of the sun 
with reference to the elevated object had a marked 
influence. Immediately below his disk, the excessive 
illumination prevented my taking altitudes by the sex- 
tant ; but on either side of it, to a distance of twenty 
degrees, I could note that the false horizon, which I 
had selected as an index of the uplift, rose as it reced- 
ed from the sun. A similarly progressive elevation of 
>the refracted bergs was observable by the unassisted 
eye. The range thus noted was from .06' to 1° 40'. 
The entire sea at this time was studded with frac- 
ments of floating ice. Jleretofore the more striking 
manifestations of this sort of refraction had occurred 
on warm sunny days, when the area immediately ad- 
jacent to US- was entirely ice-bound ; and we had re- 
marked, on several occasions, that the presence of open 
