how did watson read of the remarkable explorations of sigurson?
who was writing them down??
Seeing this post led me to reflect on the question. I have always presumed that these were published in newspapers, under headings very like "Remarkable Explorations Of Sigerson" because late 19th-century Europeans loved that sort of thing. I'm picturing something like the journalists' accounts created in Jules Verne's Michael Strogoff.
This still leaves us with the question of how the accounts get to the newspapers. Holmes would be fully capable of writing them up himself, as we know from STUD. And it would be to his advantage to get them published, to establish, very definitely, an alter ego.
So I started thinking about how Holmes might end up finding a way to send a very long-distance missive to someone who owed him a favor in Berlin, say, or even Oslo, since Sigerson is a Norwegian. And then I figured out something else, which is that from Lhasa, about six weeks' walking will take you to the Terai tea plantations (GLOR). Now, of course there are many arguments against his revealing himself to anyone, but perhaps, if he were--on the wildly improbable but not impossible chance--recognized, this itself might provide the catalyst for creating Sigerson's identity, someone whom Sherlock Holmes definitely was not.
