It consisted of the alphabet arranged in five lines, and numbered above, and at the side. Then the intersection of the number of knocks, two series with a pause between, beginning with the horizontal top figures gave the letter. It was simplicity itself when once learned.
Joe picked it up quickly, and we rapped out messages to each other as soon as we were awake. For instance, three knocks, then after a pause two more, gave the letter H.
This was the first of our morning's greetings, "Heeps better." Joe did not spell well at that time, but for the correction of his orthography it needed the schoolmaster's cane, and not a newly invented Morse sound code. So I let him spell as he liked. It lightened our days very much. And I will admit, ever after that, Joseph and I understood each other better.
Now it will hardly be believed, but I am willing to let my commercial honour stand for the truth of what I am about to say, which with those who have done business with me will be sufficient. One morning I awoke early, before the slate-blue crack, with a star wandering across it, which was the jackdaw's front door, had changed to the grey of a winter's morning. I lay on my comfortless straw couch, wondering why it was that my prison was not colder. It could not be that it was so far underground as to be warm like the bottom of a mine, by its own distance from the earth's surface. There were the exits and the entrances of the jackdaws to witness against that.
Still, though cold enough at times, the fact remained that the temperature of my prison never descended to the freezing point. Indeed, it had probably been chosen as a winter home by the birds on that account. Once or twice I had seen a flake of snow fluttering down, but these melted before they could be discerned on the oaken floor of the curious circular cellar in which I lay.
I was, as I say, pondering over these things, about home, too, and what Joseph would be doing. I almost blush to write, but I began automatically knocking out a sentence in our old "Morse" code which had amused us during the fever year.
"Is any one there?" I spelled the words out.
And I actually sat upright with wonder when I heard come through the thick oak of the partition, first five distinct knocks, then, after a pause, one.
