Now, to be left on deck, practically alone, was a bit of luck that I had not dared to hope for; and the fact that I had been, coupled with what Leroy had said about the boats, gave me an idea upon which I immediately acted.  We were still lying broadside-on to the _Gadfly_, and I had not the least doubt that on board her a constant watch was being kept upon the barque; glancing round hurriedly, therefore, and observing that all hands on the forecastle were busy with their breakfast, I slipped over the side into the mizzen chains, where I could stand without being seen from inboard, and, removing my jacket, so that my white shirt-sleeves might show up clearly against the barque's black side, I forthwith began to semaphore with my arms, waving them up and down for about a minute to attract attention.  Then, without knowing whether or not I had been successful, I proceeded to signal the following message: