The boys, then, had reason to be pleased with what they had accomplished. The superintendent kept his word, and instruments of the latest pattern were soon installed by Lineman Mickey, while the current for the line was furnished by the company's batteries, and was stronger and more constant than their own little battery had been able to give them. Nor was that all the help they had, for the trainmaster and the dispatchers took an interest in their work, and drilled them in the various abbreviations and code signals in use on the road, as well as the calls for the various offices. They were permitted to "cut in" with the main line whenever they wished; the messages which flashed over it were then repeated on their own sounders, and they could try their hands at transcribing them. Needless to say, they progressed rapidly under this tuition, which was the very best they could have had; and the day came at last when Allan, sitting at his desk sorting the mail, could understand perfectly what all the instruments about him were saying. There is within us, so scientists say, a sort of second-self which takes care of all actions which become habitual, without troubling us to think of them, or to will their performance. Thus we breathe without any effort of consciousness--a wise provision of nature, else we should die of asphyxiation as soon as we went to sleep. The muscles which control the heart keep on working of themselves from birth to death. Thus, too, while the baby must distinctly _will_ every step it takes, the child soon learns to walk or run automatically, without thinking about it at all, the muscles moving of themselves at the proper instant. So the fingers of the piano-player come to perform the duties required of them instinctively; and so, at last, the ear of the telegrapher recognizes a certain combination of sounds as having a certain meaning, and the brain has no need whatever to puzzle them out. The sounds are recorded mechanically, and the brain furnishes the translation.