La ceinture empoisonnée

A little lame actually.
The first thing I note is that Einstein had discredited and abandoned the idea of the luminiferous ether several years before this book was written. Even though not all scientists had gotten that memo by 1913, that Doyle premises his story on its existence indicates that science is not going to be a strong point in the story, though it is consistent with Doyle's “spiritualist” world view at the time which does bleed through into the story.
The opening chapter, where everyone is behaving a little peculiarly, is a particularly heavy handed foreshadowing of the crisis to come.
The last chapter retcons the global catastrophe, reminiscent of more recent films that feature similar annoying mulligans (I'm thinking of the Avengers and Superman), one can see coming from the structure of the narration: our reporter protagonist must have an audience in the end.