I knew that seclusion and solitude were very necessary for my friend in those hours of intense mental concentration during which he weighed every particle of evidence, constructed alternative theories, balanced one against the other, and made up his mind as to which points were essential and which immaterial.

Watson explains that when Holmes needs to work out a case in his mind, he needs to spend hours of time in silent solitude. Holmes’s need to self-isolate adds to his unique character and mystique and helps paint a picture of the classic genius loner who requires absolute seclusion for his genius to work. While isolation allows Holmes to work, however, it also creates lonely, eccentric characters in the novel: Holmes needs Watson’s adoration as he has few other friends, and Mr. Frankland engages in superficial legal battles just to engage with others.

The longer one stays here the more does the spirit of the moor sink into one’s soul, its vastness, and also its grim charm. When you are once out upon its bosom you have left all traces of modern England behind you, but on the other hand you are conscious everywhere of the homes and the work of the prehistoric people.

Watson observes in his first report to Holmes that the moor has a mysterious, pervasive effect on the soul the longer one spends there. Watson notes that while out on the moor, one becomes conscious of the traces of “prehistoric people.” Conan Doyle sets up a dichotomy in the novella where, symbolically, the moor represents the irrational side of the mind, a way of thinking employed by the moor’s ancient inhabitants, and London represents the rational side, developed and used by modern men. The farther away the characters stray from London and the more time the characters spend on the moor, the deeper they fall into their irrational mind.

One of these, concerning which I have said little, is the escaped convict upon the moor. There is strong reason now to believe that he has got right away, which is a considerable relief to the lonely householders of the district.

Watson tells Holmes in his first report that there exists a threat on the moor other than the hound: an escaped convict. The residents of the moor become uneasy with the idea of a convict roaming the moor at night. The convict himself lives an isolated life, scrounging for shelter and waiting for food from his sister, Mrs. Eliza Barrymore. Isolated on the moor, the people experience lives closer to the stark realities of survival, with the line between fear and safety stretching very thin.

It is not to be wondered at, for time hangs heavily in this lonely spot to an active man like him, and she is a very fascinating and beautiful woman.

Watson observes to Holmes in his first report how strange one feels to consider that Miss Stapleton, an exotic, lively beauty, lives an isolated life on the moor. Miss Stapleton’s South American beauty appears at odds with the cold monotony of the British moor and the area’s inhabitants. Watson wonders why such a person would live a life of self-imposed isolation. His keen senses pick up on this important incongruity, which turns out to be a key to unlocking the mystery of the plot.

He helps to keep our lives from being monotonous, and gives a little comic relief where it is badly needed.

Watson reports to Holmes how Mr. Frankland, one of the moor’s older inhabitants, serves as a welcome source of comic relief for him and the others. With too much time on his hands, Mr. Frankland finds a way to sue others for mostly imaginary infringements on his rights. Unlike that of Miss Stapleton, Frankland’s residency on the moor makes sense, since Frankland lives as a cantankerous eccentric. Isolation affords characters time to sink deeper into their irrationality.