STOEJSE OK T1IE PEAK. 
71 
■with instruments, had as yet taken, such an observation. I 
had a telescope and a chronometer, which I knew to be 
exceedingly correct. In the part where the sun was to 
appear the horizon was free from vapour. We perceived the 
upper limb at 4 h IS' 5.7' apparent lime, and what is very re- 
markable, the first luminous point of the disk appeared imme- 
diately in contact with the limit of the horizon, consequently 
we saw the true horizon; that is to say, a part of the sea 
farther distant than 40 leagues. Tt is proved by calculation 
that, under the same parallel in the plain, the rising would 
have began at 5 h 1/50 •#, or 11' 5T3* later than at the height 
of the peak. The difference observed was 12' 55", which arose 
no doubt from the uncertainty of the refraction for a zenith 
distance, of which observations are wanting. 
We were surprised at the extreme slowness with which 
the lower limb of the sun seemed to detach itself from the 
horizon. This limb was not visible till 4 h 5G' 5G". The 
disc of the sun, much flattened, was well defined; during 
the ascent there was neither double image nor lengthening 
of the lower limb. The duration of the sun’s rising being 
triple that which wo might have expected in this latitude, 
we must suppose that a fog-bank, very uniformly extended, 
concealed the true horizon, and followed the sun in its 
ascent. Notwithstanding the libration of the stars,* which 
we had observed towards the east, wc could not attribute 
the slowness of the rising to an extraordinary refraction of 
the rays occasioned by the horizon of the sea ; for it is pre- 
cisely at the rising of the sun, as Lo Gent.il daily observed at 
Pondicherry, and as 1. have several times remarked at Cu- 
mana, that the horizon sinks, on account of the elevation of 
temperature in the stratum of the air which lies immediately 
over the surface of the ocean. 
The road, which we were obliged to clear for ourselves 
across the Malpays, was extremely fatiguing. The ascent is 
steep, and the blocks of lava rolled from beneath our feet. I 
can compare this part of the road only to the Moraine of the 
* A celebrated astronomer, Baron Zach, lias compared this phenomenon 
of an apparent libration of the stars to that described in the Georgies 
(lib. 1 , v, 305). But this passage relates only to the falling stars, which 
the ancients, (like the mariners of modern times) considered as a prognos- 
tic of wind. 
