Final answer:
The word 'bitter' in Theodore Roosevelt's excerpt from 'The Naval War of 1812' contributes to a mood of tension and unease, emphasizing the resentment towards England's triumphant naval dominance in the early 19th century.
Step-by-step explanation:
The use of the word bitter to describe the dread that European nations felt toward England's naval power effectively adds to the mood of the excerpt by painting a picture of intense negativity and resentment. The connotation of the word suggests an experience that is profoundly painful and hard to endure, which would make the mood of the text one of tension and unease. It amplifies the impact of England's dominance during the early 19th century, particularly relating to the triumphant position of its navy and the fear it instilled in other nations.