When describing to Holmes the habits of his assistant “Spaulding” (later revealed to be the criminal Clay), Wilson uses a simile, as seen in the following passage:
“Never was such a fellow for photography. Snapping away with a camera when he ought to be improving his mind, and then diving down into the cellar like a rabbit into its hole to develop his pictures. That is his main fault, but on the whole he’s a good worker.”
The simile here—in which Wilson describes Clay as “diving down into the cellar like a rabbit into its hole to develop his pictures”—captures the consistency and tenacity with which Clay hid away in the cellar of the pawnbroker’s office to “develop his photos” at odd hours during the workday.
This moment is also an example of foreshadowing because, as readers later learn, Clay was not developing photos at all, but digging a tunnel from Wilson’s office to the nearby bank in order to enter the bank from below and rob it. The simile adds to the foreshadowing as the image of a rabbit “diving […] into its hole” mirrors Clay diving into the tunnel that he was secretly digging beneath Wilson’s building. This is one of the many examples in the story of appearances not being exactly what they seem—Clay is not a simple photographer but a skilled criminal.
In an example of foreshadowing, Holmes tells Watson as they walk away from Wilson’s pawnbroker office that he wanted to meet Wilson’s assistant (Clay) in order to look at his knees:
“Evidently,” said I, “Mr. Wilson’s assistant counts for a good deal in this mystery of the Red-headed League. I am sure that you inquired your way merely in order that you might see him.”
“Not him.”
“What then?”
“The knees of his trousers.”
“And what did you see?”
“What I expected to see.”
“Why did you beat the pavement?”
“My dear doctor, this is a time for observation, not for talk.”
Watson hypothesizes that Holmes wanted to meet Clay to get a visual on this man who is so important to the case, while Holmes clarifies that he merely wanted to meet the man to see “the knees of his trousers.” Because Holmes does not explain to Watson exactly what he saw on Clay’s trousers, this is an example of foreshadowing. From this moment on, readers—like Watson—are wondering what was so significant about the knees of Clay’s pants.
The answer, of course, ends up being that Clay’s knees were covered in dirt, a sign that he was digging a tunnel from Wilson’s office to the nearby bank in order to rob it. This detail is also foreshadowed via Holmes’s decision to “beat the pavement”—something he does because, as it is later revealed, he needs to see if it is hollow (because of the newly dug tunnel underneath it). Once again, with his excellent observational skills, Holmes is able to see beyond mere appearances, while those around him are not.
