IMPROVEMENTS IN THE MEANS AND APPARATUS FOR NAVIGATING THE AIR
Year: 1868

page_text: PROVISIONAL SPECIFICATION left by Andrea Crestadoro at the Office
of the Commissioners of Patents, with his Petition, ou the 3rd
June 1868.
I, ANDREA CRESTADORO, of No. 19, Rumford Street, Chorlton-upon-
Medlock, in the County Palatine of Lancaster, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN THE MEANS AND APPARATUS
FOR NAVIGATING THE AIR," to be as follows:-
I provide a hollow air-tight vessel similar, as far as general shape is
concerned, to ordinary balloons, but made of metallic sheet or other
fire-proof material and having no openings to the external air except
through two taps so placed and arranged that they are on a different
level, say one near the bottom and the other on or near the top of the
balloon, and they can be easily operated upon both jointly and separately
at the will of the air captain as means of communication between the
internal and external air. To the bottom of this vessel is attached a
furnace forming, as it were part and parcel of the balloon, and being
so fitted and arranged that the balloon itself is to the furnace as a
boiler. On the fire and the chimney or flue is a pipe passing through
the interior of the balloon to the top outside for the discharge of the

page_text: aeriform products of combustion into the atmosphere. The balloon is
also provided with suitable propeller or propellers worked by any suitable
motive power. Finally a car is attached to the balloon on the ordinary
or other suitable plan.
"The operation is this:-The balloon being full of common air the
lower tap closed and the upper one open, and the fire in the furnace
lighted, the internal temperature of the balloon is gradually raised by
the heat, causing a proportionate expansion and consequent escape of
a quantity of the internal air through the open top; and as it is known
that common air when rarefied by heat loses weight at the rate of one
both part of that which it possesses at the temperature of 32° Fahreneit,
which weight at this temperature is known to be 1.29 oz. per cubic
foot; this determines the rate of temperature at which the internal
air of the balloon should be raised as compared with the cubic capacity
and intended gross weight of the balloon. Thus, for instance, if a balloon
be 200 feet diameter corresponding to a capacity of about 4,188,792
(cubic feet, and its internal temperature be raised to 230° F. corresponding
to an expansion and consequent lightness or tendency to ascend at the
rate of about one-third of an ounce per cubic foot, the total ascending
or lifting power thus obtained will amount to 4,188,792 times one-
third of an ounce, being more than 38 tons ascending power available
to balance in the air a balloon of equal gross weight. The temperature
being increased or lowered, the balloon will ascend or descend in pro-
portion. As to the lower tap, this is intended as a means of allowing,
when required, external air to enter the interior of the balloon for the
purpose of lowering its temperature by refilling it wholly or in part,
as the case may require, with cold air as supplied by the atmosphere,
while at the same time the heated or rarefied air would find its exit
through the upper tap.