Because of the advance of science, many mysterious places have lost their mystique. We know a lot about Venus and Mars and a little about the large outer planets and their satellites. If all goes well, Pluto will soon divulge some of its secrets.
While it is pleasant and even thrilling to learn more about the universe, the resultant knowledge is a hindrance to writers of science fiction who like to exploit cosmic mysteries. I doubt whether H. G. Wells would write War of the Worlds if he were living in our present era. Because respectable scientists continue to imagine that life once existed on Mars, the Martian past is still a mysterious setting for possible science fiction stories. Future colonization of solar system bodies is another fertile field for science fiction. However, if an author wants to write about a current Martian civilization, he’ll have to explain how they managed to hide themselves from the prying eye of science all this time.
Since Sir Arthur Conan Doyle wrote science fiction in the first part of the twentieth century, he did not even have to resort to Mars as a setting for his works.. Since aviation was in its infancy, the upper regions of the atmosphere were still somewhat mysterious. As a result, when he wrote The Horror of the Heights, Sir Arthur Conan Doyle could pretend that jungles existed about forty thousand feet above the earth. These jungles did not have trees, of course. They were airy regions populated by huge monsters with air bubbles or bladders that gave them buoyancy.
The plot of the story is simple. Some of the pilots that fly to an altitude of thirty thousand feet mysteriously disappear. Their aircrafts fall to earth, but the bodies of the pilots are missing. In one case, there is a body, but the pilot somehow lost his head.
Mr. Joyce-Armstrong, the best pilot in England, believes that monsters populate the regions above the 30,000-foot level, and he wants to prove it. In his first flight, he reaches an altitude of 41,300 feet. He sees beautiful iridescent bubbles of air that look something like jellyfish. Then he encounters a monster, becomes enmeshed in its tentacles, but escapes when he hits one of the monster’s bladders with his shot gun. Evidently the monster has various bladders that buoy it up and keep it level. When one bubble bursts, some parts of the monsters body are more buoyant than others. As the result, it loses its equilibrium.
He returns to the earth and writes down what he has experienced. However, he hesitates to tell his story to the world before he has some proof. So he reascends to the ethereal regions, hoping to capture some of the iridescent bubbles. This time he is trapped by monsters and does not return.
He has somehow managed to continue his journal while flying and trying to get away from the monsters. It falls to earth and lands in a field, where an agricultural laborer named James Flynn finds it.
Sir Arthur Conan Doyle embellishes this plot with interesting details. It is included in a work entitled Tales of Terror and Mystery, which is offered online by Project Gutenberg. It is interesting to read.
Project Gutenberg: Tales of Terror and Mystery by Sir Arthur Conan Doyle