'Because I don't know what it shall be; I've fixed up everything I can think of.' 'And you are like Alexander, sighing for more worlds to conquer. Is that it?' 'Not exactly, for there is plenty for one to do, if I could only find out what it is.' 'Have you ever made a balloon?' The boy laughed. 'You were asking for the cat the other day, and wondering what had become of her. I didn't tell you that the last I saw of her was through the telescope, she being about two miles up in the clouds, and going about fifty miles an hour.' 'I thought you looked as though you knew something about her,' replied the mother, trying to speak reprovingly, and yet smiling in spite of herself. 'Can't you tell me something to make?' finally asked the boy. 'Yes; there is something I have often thought of, and wonder why it was not made long ago; but you are not smart enough to do it, Johnny.' 'Maybe not; but tell me what it is.' 'It is a man that shall go by steam!' The boy lay still several minutes without speaking a word and then sprung up. 'By George! I'll do it!' And he started out of the room, and was not seen again until night. His mother felt no anxiety. She was pleased; for, when her boy was at work, he was happy, and she knew that he had enough now, to keep him engaged for months to come. So it proved. He spent several weeks in thought, before he made the first effort toward constructing his greatest success of all. He then enlarged his workshop, and so arranged it, that he would not be in danger of being seen by any curious eyes. He wanted no disturbance while engaged upon this scheme. From a neighboring foundry, whose proprietor took great interest in the boy, he secured all that he needed. He was allowed full liberty to make what castings he chose, and to construct whatever he wished. And so he began his work. The great point was to obtain the peculiar motion of a man walking. This secured, the man himself could be easily made, and dressed up in any style required. Finally the boy believed that he had hit upon the true scheme. So he plied harder than ever, scarcely pausing to take his meals. Finally he got the machine together, fired up, and with feelings somewhat akin to those, of Sir Isaac Newton, when demonstrating the truth or falsity of some of his greatest discoveries, he watched the result. Soon the legs begin moving up and down, but never a step did they advance! The power was there, sufficient to run a saw-mill, every thing seemed to work, but the thing wouldn't go! The boy was not ready to despair. He seated himself on the bench beside the machine, and keeping up a moderate supply of steam, throwing in bits of wood, and letting in water, when necessary, he carefully watched the movement for several hours. Occasionally, Johnny walked slowly back and forth, and with his eyes upon the 'stately stepping,' endeavored to discover the precise nature of that which was lacking in his machine.