ing structure.

PART III. AEROSTATICS

I. BEGINNINGS

Francesco Lana, with his 'aerial ship,' stands as one of the first great
exponents of aerostatics; up to the time of the Montgolfier and
Charles balloon experiments, aerostatic and aerodynamic research are so
inextricably intermingled that it has been thought well to treat of them
as one, and thus the work of Lana, Veranzio and his parachute, Guzman's
frauds, and the like, have already been sketched. In connection with
Guzman, Hildebrandt states in his Airships Past and Present, a
fairly exhaustive treatise on the subject up to 1906, the year of its
publication, that there were two inventors--or charlatans--Lorenzo de
Guzman and a monk Bartolemeo Laurenzo, the former of whom constructed
an unsuccessful airship out of a wooden basket covered with paper,
while the latter made certain experiments with a machine of which no
description remains. A third de Guzman, some twenty-five years later,
announced that he had constructed a flying machine, with which he
proposed to fly from a tower to prove his success to the public. The
lack of record of any fatal accident overtaking him about that time
seems to show that the experiment was not carried out.

Galien, a French monk, published a book L'art de naviguer dans l'air
in 1757, in which it was conjectured that the air at high levels was
lighter than that immediately over the surface of the earth. Galien
proposed to bring down the upper layers of air and with them fill a
vessel, which by Archimidean principle would rise through the heavier
atmosphere. If one went high enough, said Galien, the air would be two
thousand times as light as water, and it would be possible to construct
an airship, with this light air as lifting factor, which should be as
large as the town of Avignon, and carry four million passengers with
their baggage. How this high air was to be obtained is matter for
conjecture--Galien seems to have thought in a vicious circle, in which
the vessel that must rise to obtain the light air must first be filled
with it in order to rise.

Cavendish's discovery of hydrogen in 1776 set men thinking, and soon a
certain Doctor Black was suggesting that vessels might be filled with
hydrogen, in order that they might rise in the air. Black, however, did
not get beyond suggestion; it was Leo Cavallo who first made experiments
with hydrogen, beginning with filling soap bubbles, and passing on to
bladders and