This photo is of a compensated balloon barometer circa 1860 that demonstrates the development of balloon technology. The first hot air balloon, the Montgolfier Balloon, began simply by using hot air to make the device float. As balloons continued to develop, hydrogen gas replaced heated air, and other tools were used to make balloons function more efficiently: gasometers; sand ballasts to balance; iron, zinc, and water casks to boost the hydrogen gas; and barometers to measure atmospheric compression were used in this new form of flight.   

The significance of this historical novel, published in 1870, lies in its content, as the work recounts the mythology of flight in antiquity; the development of balloon flight through the Montgolfiers, Blanchard, and other innovators; and the applications of hot air balloons in warfare and meteorology. Most importantly, it establishes hot air balloons as means of travel. The book recounts the adventures of inventors and aeronauts who frequently made history in coming decades with their expeditions to cross the Adriatic Sea and the entire continent of Europe.    

This novel, published in 1922, discusses the biography of Count Zeppelin and the emergence of his famous airship. In 1894, over a century after the first hot air balloon flight, Count Zeppelin developed his design of the first rigid airship that did not collapse beneath its own weight. On July 2nd, 1900, Count Zeppelin successfully flew the first rigid airship in history. While at first used as a means of entertainment and travel, in coming years, Zeppelin airships developed into machines of war mounted with guns and capable of dropping bombs. The book recounts how roughly 88 of Zeppelin’s airships were used in WWI, establishing it as a machine suited for both flight and modern warfare.