What Goes Up, Must Come Down

Diagram of James Glaisher’s balloon flight from Wolverhampton to Solihull in England on 18 August 1862. Illustration drawn by Vincent Brooks, Day & Son.

I love a drawing that tells a story. Here’s an illustration that does just that; it’s a diagram showing the flight path of James Glaisher’s balloon on 18 August 1862, which travelled between Wolverhampton and Solihull, just outside Birmingham in England. It’s essentially a graph that plots altitude over time, with some embellishments added for effect. The story being told is in the graph’s line, which ascends and descends just as the balloon did during its flight. We can get a sense of the major events that took place by watching the line as it progresses from left to right. First, we have the main ascent at the far left, which continues up to roughly 11,500’, followed by a descent back down to 3,300’. after this partial descent, the balloon makes it’s main ascent, all the way up to 23,500’, followed by some bouncing around before the main descent, all the way back to the ground. The whole journey took a little over three hours, with a patchy set of clouds present between 4000’ and 12,000’.

The aeronaut has a couple options to control the ascent and descent of the balloon. It’s a balancing act between the amount of gas or the temperature inside the balloon, and the weight being carried by the balloon. In order to ascend, the aeronaut can shed weight from the balloon or raise the temperature of air in the balloon, which will cause it to rise. In order to descend, the aeronaut can either release gas from the balloon or wait for the heated air inside to cool, which will cause it to fall. Each of the three events described above involved one of these actions. At the first peak, the valve was opened, which caused the balloon to begin falling. At the subsequent valley, sand was released from the basket, which caused the main ascent. Once the balloon reached the next peak, there was some deliberating about whether or not to go higher, and the decision was made to begin descending.

My description of the events comes from text accompanying the above illustration in the 1871 book Travels in the Air, which chronicles the major balloon flights of James Glaisher, Camille Flammarion and Gaston Tissandier.[1] Still, even without this text, the illustration above does a wonderful job of telling nearly the whole story.

Check out other posts about aeronautics and balloons here.


[1] : Glaisher, James. Travels in the Air. London: Richard Bentley & Son, 1871. 48-50.