Just a noise, that is all. But a very significant noise to Miss Nathalie Rogers, or Nattie, as she was usually abbreviated; a noise that caused her to lay aside her book, and jump up hastily, exclaiming, with a gesture of impatience:—"Somebody always 'calls' me in the middle of every entertaining chapter!" For that noise, that little clatter, like, and yet too irregular to be the ticking of a clock, expressed to Nattie these four mystic letters:—"B m—X n;" which same four mystic letters, interpreted, meant that the name, or, to use the technical word, "call," of the telegraph office over which she was present sole presiding genius, was "B m," and that "B m" was wanted by another office on the wire, designated as "X n." A little, out-of-the-way, country office, some fifty miles down the line, was "X n," and, as Nattie signaled in reply to the "call" her readiness to receive any communications therefrom,...