Why were Holmes and Watson 'deprived' of their residence in The Adventure Of The Three Students??

Holmes was researching early English characters, and they'd taken rooms closer to the library where Holmes was working.

We were residing at the time in furnished lodgings close to a library where Sherlock Holmes was pursuing some laborious researches in early English charters—researches which led to results so striking that they may be the subject of one of my future narratives.