Much careful work had been done for him there, and the people were willing to oblige him, and promised that the piece should certainly be ready before Christmas Day, and as much earlier as possible, and should be made with the greatest exactness which the most precise machinery and the most careful work could ensure.

This being settled, Overholt returned to New York and went to two or three places in the Bowery, well known to him, where he bought certain fine tools and pieces of the most perfectly turned steel spring, and several other small objects, which he needed for the construction of the new tangent-balance he had to make for the reversed curve.  Finally, he bought a silver watch like the one Newton had sold, and a new pair of skates, presents which the boy certainly deserved, and which would make a very good show at Christmas, when they were to be produced.  He felt as if he had come into a large fortune.

Moreover, when he got out of the train at his own station he went into the town, and ordered beforehand the good things for the feast, though there were three weeks still, and he wanted to pay for them in advance, because he felt inside of himself that no one could be quite sure of what might happen in twenty-one days; but the dealers flatly refused to take his money, though they told him what the things would cost.  Then Overholt did almost the only prudent thing he had done in his life, for he took the necessary money and five dollars more and sealed it up in an envelope, which he put away in a safe place.  The only difficulty would lie in remembering where the place was, so he told Newton about it, and the boy wrote it down on a piece of paper which he pinned up in his own room, where he could see it.  There was nothing like making sure of that turkey, he thought.  And I may as well say at once that in this matter, at least, no untoward accident occurred, and the money was actually there at the appointed time.  What happened was something quite different, and much more unexpected, not to say extraordinary and even amazing; and in spite of all that, it will not take very long to tell.

Meanwhile, before it happened, Overholt and the boy were perfectly happy.  All day long the inventor worked at the tangent-balance, till he had brought it to such perfection that it would be affected by a variation of one-tenth of one second in the aggregate speed of ten revolutions, and an increase or decrease of a tenth of a grain in the weight of the volume of the compressed air.  It was so sensitive that John Henry and Newton trod cautiously on the floor of the workshop so as not to set it vibrating under the glass clock-shade, where it was kept safe from dust and dampness.

After it had been placed there to wait for the casting, the inventor took the engine to pieces and made the small changes that would be necessary before finally putting it together again, which would probably occupy two days.