The Mysterious Island Part 1 Chapter 10 - The Engineer's Invention. Volcanic Soil.

In which the resourceful engineer demonstrates his ingenuity by fashioning a burning-glass to ignite a fire that roasts their game, and the party embarks upon a demanding ascent of a volcanic mountain to survey the land from its summit. Their arduous climb reveals the rugged beauty and mysterious nature of the terrain as they press onward through forests, steep slopes, and volcanic rock towards the summit, where the presence of a watery horizon hints at the true nature of their solitary resting place.