OBSERVATIONS IN FOUR BALLOON ASCENTS. 
319 
height of 3700 feet the upper surface of the cloud was reached, and the sun was seen 
shining through thin cirrous clouds, at a great height. The height of the upper 
surface of the cloud was again observed during the descent at 4** 6™ to be 3450 feet. 
When the balloon was close to the clouds, it was remarked that the general level of 
the surface was very uniform, presenting, however, a hillocky appearance ; the irre- 
gularities being small, apparently not exceeding a very few feet. Shortly after clearing 
the clouds, a shadow of the balloon was seen on the surface fringed with a glory ; with 
this shadow as a centre, there was also observed a circle of whitish light, the outer 
edge of it slightly tinged with yellow ; its diameter being estimated at 80°. About 
this time there was noticed, stretching for a considerable length in a serpentine 
course over the surface of the cloud, a well-defined belt having the appearance of a 
broad road, both sides being strikingly distinct. When the balloon had attained a 
height of above 12,000 feet, Mr. Green, who had been watching its motion with 
reference to the clouds below, decided that, as it seemed to be moving rapidly from 
N.W., it would be prudent to descend below the clouds, to ascertain our position 
with reference to the sea, and if there should be space enough to ascend a second 
time to a greater height. It was found, however, on descending, that we were 
already very near the sea, indeed, moving along the river Thames within a short 
distance of its mouth. A second ascent being thus unadvisable, the descent was 
made at 4*^ 20“ p.m. on the North bank of the Thames, between the villages of 
South Benfleet and Rayleigh in Essex, about 30 miles east of London. The average 
rate of motion was thus about 18 miles an hour, but in the higher part of our course 
it must have been considerably more. 
When about 3000 to 4000 feet above the clouds they were examined with the 
polariscope. The reflected light from the clouds next the sun showed no trace 
whatever of polarization ; the slightly bluish-grey clouds on the side from the sun 
showed very slight symptoms of polarization, the light of the sky being strongly 
polarized. 
Fourth Ascent, November 10. — This ascent had been delayed for some days, owing 
to the unfavourable state of the weather, the wind having been generally from a 
westerly quarter. On the 10th the surface wind and the lower current of scud were 
moving very slowly from about N.E. : the upper clouds were only occasionally visible, 
and seemed to proceed from about N.N.W. The ascent commenced at 2'* 21“ 40® p.m. 
At a height of 500 feet the first cloud, thin scud, was entered, the upper surface 
being 19/0 feet high. A space of 2000 feet was clear of clouds, and at 4000 feet the 
second stratum of clouds was reached, its upper surface being found to be 4900 feet 
high. After this no clouds were met with, the sun shining through thin cirrous 
clouds, which must have been at a very great height. From notes taken at Vauxhall 
by Mr. Gassiot, it appears that, at starting, the balloon moved towards south-west 
until 2^ 26“, when, just as it had reached the upper surface of the first stratum of 
clouds, or at a height of about 2000 feet, the direction became easterly. Bearings 
MDCCCLIII. 2 u 
