broad road."

Being now at 12,000 feet, Green thought it prudent to reconnoitre his
position, and, finding they were near the sea, descended at 4.20 p.m.
at Rayleigh, in Essex. Some important notes on the polarisation of the
clouds were made.

The fourth and final voyage was made in a fast wind averaging fifty
knots from the north-east. Thin scud was met at 1,900 feet, and an upper
stratum at 4,500 feet, beyond which was bright sun. The main shift
of wind took place just as the upper surface of the first stratum was
reached. In this ascent Welsh reached his greatest elevation, 22,930
feet, when both Green and himself experienced considerable difficulty
in respiration and much fatigue. The sea being now perceived rapidly
approaching, a hasty descent was made, and many of the instruments were
broken.

In summarising his results Welsh states that "the temperature of the
air decreases uniformly with height above the earth's surface until at a
certain elevation, varying on different days, decrease is arrested,
and for the space of 2,000 or 3,000 feet the temperature remains nearly
constant, or even increases, the regular diminution being again resumed
and generally maintained at a rate slightly less rapid than in the lower
part of the atmosphere, and commencing from a higher temperature than
would have existed but for the interruption noticed." The analysis
of the upper air showed the proportion of oxygen and nitrogen to vary
scarcely more than at different spots on the earth.

As it is necessary at this point to take leave of the veteran Green as a
practical aeronaut, we may here refer to one or two noteworthy facts and
incidents relating to his eventful career. In 1850 M. Poitevin is said
to have attracted 140,000 people to Paris to look at an exhibition of
himself ascending in a balloon seated on horseback, after which
Madame Poitevin ascended from Cremorne Gardens in the same manner, the
exhibition being intended as a representation of "Europa on a Bull."
This, however, was discountenanced by the authorities and withdrawn.
The feats were, in reality, merely the repetitions of one that had been
conceived and extremely well carried out by Green many years before--as
long ago, in fact, as 1828, when he arranged to make an ascent from the
Eagle Tavern, City Road, seated on a pony. To carry out his intention,
he discarded the ordinary car, replacing it with a small platform,
which was provided with places to receive the p