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Lana's airship
To understand who the Jesuits were, one must study their founders. Ignatius of Loyola was born in Spain of noble parents. After a carefree youth until he entered the army and was wounded. During his convalescence he had a religious conversion. His "spiritual exercises" are used to this day.
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n November 11, 1647 a sixteen year old Italian
boy became a novice in the Society of Jesus in Rome. That in itself was
not extraordinary. It was the mind of the young man that was extraordinary.
He was one of the Jesuits who shone in the world of scientific ideas.
Francesco Lana was the first person known to have systematically applied
mathematics to solving the problems of lighter-than-air flight.
You may have seen sketches of a gondola-like ship upheld by four globes
and steered by a sail. Francesco's concept was that if one were to eliminate
all the air from a sphere of thin metal, it would become lighter than
air and able to rise. So far, his reasoning was based on sound principles.
Blaise Pascal had shown that air pressure decreases with altitude. Two
scientists at Magdeburg later showed that it would take a team of eight
horses to overcome outside air pressure and pull apart two halves of a
heavy sphere that had been emptied of air using such a vacuum pump. Then
Robert Boyle wrote a treatise on vacuum, based on experiments conducted
with the vacuum pump that Robert Hooke built for him. Francesco knew of
their work.
However, technology only works when all natural factors that affect it
are taken into account. Francesco thought that the spherical shape of
the globes would hold them rigid. He was wrong. He did not realize that
the same outside air pressure which made it so hard for the horses to
separate the experimental sphere in Magdeburg would squash his flimsy
globes. To keep them from being flattened, a lighter gas of equal pressure
was needed inside.
In the 1780s, the Montgolfier brothers grasped this principle and built
the world's first balloons, which flew using hot air, which is lighter
than the air around it because the heat has expanded it. (When the air
cools, it loses its buoyancy.) Today we use helium.
Meanwhile, Francesco answered a number of objections. Some felt the ship
would have no lift. Francesco said Archimedes' discoveries proved that
lighter bodies float in heavier. Others thought that the flying ship would
fly off into outer space, but Francesco argued that as the density of
the atmosphere fell with altitude, the ship would lose buoyancy.
Francesco was interested in other technological ideas. In fact, he gathered
a number into a book. These included a sewing machine, telescopes, microscopes,
an invention for communicating at a distance, a method for writing in
code and so forth.
But the Jesuit was also interested in spiritual matters and wrote a book
on asceticism (the practice of strict self denial). He died in his home
town in 1687, but his ideas and the mathematics behind them continued
to be discussed right up into the twentieth century, when airships came
into widespread use.
Resources:
- Boreham, F. W. "The Aeroplane" in The Golden Milestone. London: Epworth, 1918.
- Wilhelm, B. "Francesco Lana." Catholic Encyclopedia. Robert
Appleton Co., 1910.
- Various encyclopedia and internet articles such as Jesuits in Science (www.jesuitsinscience.org)
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