Why did Sherlock Holmes tap the sidewalk with his cane?

Answer 1

Conan Doyle only uses the word 'cane' for Holmes' walking-stick in two stories. First, when he confronts the speckled band in 'The Adventure of the Speckled Band,' and second when he struck one ledge of Thor Bridge to determine if a mark could be left in 'The Problem of Thor Bridge.' On every other occasion, including when he beat bodies in the dissecting rooms of St. Bart's hospital to verify the degree of bruising after death in 'A Study in Scarlet' and when he thumped the pavement in 'The Red-Headed League' to ascertain the direction of the tunnel, the word stick or walking-stick is employed.

The short answer to the question is, yes.

Answer 2

{| |- | This is from the Red Headed League. Holmes was attempting to see if he heard an echo. He suspected that a tunnel was being built and wanted to see if it was coming out the front of the shop. |}