To emphasize the urgency of protecting nature, Muir uses a metaphor comparing soil to a "richest treasury" that is being rapidly depleted.
This metaphor connects to the central theme of protecting nature by highlighting the value of natural resources and the consequences of their destruction.
Muir uses a vivid metaphor to describe the devastating impact of human actions on the environment, portraying once-thriving streams as "dry skeletons."This metaphor reinforces the central theme by illustrating the fragility of nature and the irreversible damage caused by human exploitation. Muir employs a strong contrast between the past and present state of forests to underscore the extent of environmental degradation.