"Like Sir George Cayley's balloon, his own was an ellipsoid. Its
length was thirteen feet six inches—height, six feet eight
inches. It contained about three hundred and twenty cubic feet of
gas, which, if pure hydrogen, would support twenty-one pounds
upon its first inflation, before the gas has time to deteriorate
or escape. The weight of the whole machine and apparatus was
seventeen pounds—leaving about four pounds to spare. Beneath the
centre of the balloon, was a frame of light wood, about nine feet
long, and rigged on to the balloon itself with a network in the
customary manner. From this framework was suspended a wicker
basket or car.
"The screw consists of an axis of hollow brass tube, eighteen
inches in length, through which, upon a semi-spiral inclined at
fifteen degrees, pass a series of steel wire radii, two feet
long, and thus projecting a foot on either side. These radii are
connected at the outer extremities by two bands of flattened
