OBSERVATIONS IN FOUR BALLOON ASCENTS. 
317 
barometer was always read first, and immediately afterwards the thermometers and 
hygrometers; the whole time occupied being only a few seconds, the error, arising 
from the observations not being strictly simultaneous, must be very small. Note- 
books were provided with columns ruled and headed for the different instruments. 
§ 3. Circumstances of the Ascents and General Observations. 
The ascents were made with Mr. C. Green’s large balloon, well known by the 
name of the ‘‘ Royal Nassau.” It has been fortunate, for the success of these expe- 
riments, that the Kew Committee obtained the cooperation of Mr. Green, whose 
pre-eminence as a skilful aeronaut has been established by upwards of 500 ascents ; 
and whose control over his balloon is so complete, that no one who accompanies him 
can be otherwise than relieved from apprehension, and free to devote his attention 
calmly to the work before him. Mr. Green on all occasions showed the most 
anxious desire to contribute to the success of experiments, in which he took great 
interest. 
The ascents took place from the Royal Vauxhall Gardens, which were liberally 
placed at the disposal of the Committee by Mr. Wardell, the Lessee. The balloon 
was inflated with carburetted hydrogen gas, obtained from the Vauxhall and Phoenix 
Gas-works. 
First Ascent, August If.— The weather, previously to the Ifth, had been somewhat 
variable; on the 16th the wind changed from S.E. to S.W., and on the day of ascent 
it was from south. Clouds covered about three-fourths of the sky, the lowest 
stratum being a few detached masses of loose cumulus ; a dense mass of cirrostratus 
(or stratus) being above, with perhaps occasional patches of cumulus intermediate. 
The ascent commenced at S'* 49'“ p.m., after considerable difficulty had been expe- 
rienced in the preliminary arrangements, owing to the force of the wind. A short 
time was lost at first in the attempt to put the instruments into more convenient 
order, and also from the novelty of the situation. The lowest clouds, which extended 
only over a small area, and were not near the balloon, were passed before they 
were noticed ; their height was estimated at about 2500 feet. Between this height 
and about 13,000 feet, the air seemed free of clouds; after this, although the 
balloon was never in actual cloud, there seemed to be occasional masses of loose 
cumulus at no great distance. When at the greatest elevation, there was, at appa- 
rently a short distance above us, a thick mass of cloud, which was probably the 
cirrostratus which had been seen from the earth. About this time, and while still 
rising, a few small star-shaped crystals of snow about aJ^th of an inch diameter fell 
upon us. The sun was almost constantly obscured throughout the ascent. The 
descent commenced at 4*' 46'“ p.m., and the earth was reached about 5^ 20'“ p.m., 
near Swavesey in Cambridgeshire, about 57 miles north of London. There seems to 
have been little, if any variation in the direction of the balloon’s flight : it would 
