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Tuesday, 12 January 2016

The flight of Pilatre de Rozier, 1783



On 21st November 1783 an unsung hero became the first man to do what millions now take for granted every day – he made the first untethered flight.

This was Pilâtre de Rozier, a French physicist, who, with a colleague, floated across the River Seine in Paris in a hot-air balloon built by the Montgolfier brothers.

The flight came after a series of experiments by the Montgolfier brothers, Joseph and Etienne, that had involved a sheep, a duck, a rooster, and de Rozier. Although considerable interest had been shown by all and sundry in these experiments, there was a constant fear that lifting human beings above the ground would be dangerous, hence the use of animals in the early attempts, in which the balloon was tethered to a 90 foot rope.

When it was proposed to send men to this dizzying height the local officials suggested that two criminals, already sentenced to death, should be put in the balloon, but King Louis XVI overruled them and allowed the Montgolfiers and then de Rozier to go aloft.

The first flight without a tether went perfectly smoothly, lasting 25 minutes, covering five miles and reaching a height of 1500 feet.

It was witnessed by, among thousands of others, the American ambassador to Paris, Benjamin Franklin. When a friend of his remarked that the flight would prove to be of little use in the long run, Franklin made the perceptive and prophetic remark: “And of what use is a new-born baby?”

Pilâtre de Rozier did not live long to enjoy his celebrity. Two years later he attempted a balloon flight across the English Channel. He was aware of the lighter-than-air properties of hydrogen and so he placed an extra hydrogen balloon on top of the hot air balloon. As a physicist he should also have been aware that hydrogen and heat do not mix well, but the oversight cost him his life when the hydrogen duly exploded.


© John Welford