d France by a north-west wind. Two hours and a half after
it had been let off it was found in a field about nine miles from Lille.
The balloon carried a letter, instructing the finder of the balloon to
communicate with William Boys, Esq., Sandwich, and to state where and at
what time it was found. This request was complied with.

On the 19th of February a similar balloon, five feet in diameter, was
sent up from Queen's College, Oxford. It was spherical, and was made of
Persian silk, coated with varnish. It was the first balloon sent up from
that city.

De Saussure makes mention, in a letter dated from Geneva, the 26th
of March, 1784, of certain experiments made in that town with the
electricity of the atmosphere by means of fixed balloons--i.e., balloons
attached to the earth by ropes, which gave forth sparks and positive
electricity.

Mention is also made of a certain M. Argand, of Geneva, who had the
honour of making balloon experiments at Windsor in the presence of King
George III., Queen Charlotte, and the royal family. About this time
(1784) balloons became "the fashion," and frequent instances occur of
their being raised by day and night, by means of spirit-lamps, to the
great delight of multitudes of spectators.

A letter from Watt to Dr. Lind, of Windsor, dated from Birmingham, 25th
December, 1784, narrates an experiment made the summer preceding with
a balloon inflated with hydrogen. The balloon was made of fine paper
covered with a varnish of oil and filled two-thirds with hydrogen gas,
and one-third common air. To the neck of the balloon was attached a sort
of squib two feet long, the fuse of which was ignited when the balloon
was inflated. The night was calm and dark, and a great multitude was
assembled to witness the ascent, which was accomplished with a success
that gave delight to all; for, at the end of six minutes the fuse
communicated with the squib, and the explosion was like the sound of
thunder. The men who saw it from a distance, but were not present at
its ascent, took it for a meteor. "Our intention," says Watt, "was, if
possible, to discover whether the reverberating sound of thunder was
due to echoes or to successive explosions. The sound occasioned by the
detonation of the hydrogen gas of the balloon in this experiment, does
not enable us to form a definite judgment; all that we can do is to
refer to those who were near the balloon, and-who affirm that the sound
was like that of thunder."