The sky was clear, with not a breath of wind, and the world seemed as quiet as an oil painting.
On the parade ground of the Paris Army Officer Academy, Joseph, along with dozens of officers, looked up, staring at the small gray spot in mid-air.
Jacques-Étienne Montgolfier enthusiastically introduced, "Your Highness, later we found that silk was not only expensive but also not very airtight.
"After repeated trials, we chose to bond paper and silk together to make the balloon envelope, which worked quite well.
"The current hot air balloon is very tough, and its weight has also been reduced by 35% compared to before."
Indeed, the object floating in the sky at this moment was a hot air balloon, the military version of which had been improved multiple times.
As early as ten years ago, the Mongolfier brothers from the south of France invented the world's first hot air balloon and demonstrated it at the Palace of Versailles.
