he door and glanced inside.

"Can you see anything wrong, sir?" queried the old butler eagerly.

"Not yet. I've got to make a more thorough examination."

"Likely you have. But whatever's the matter, you'll find it--I know
that. I never see such a man for clocks as you in all my born days; an'
the master, he say the same. 'Mr. McPhearson will soon get Seventeen
into line,' he says, an' I know you will, sir. Don't you always?"

In the meantime Christopher had peeped inside the clock.

"Why, look at the great lead weight!" ejaculated he.

"Yes. Many old clocks had weights such as this, which were pulled up
when the clock was wound and gradually dropped as the clock ran down.
Sometimes a stone was used; sometimes even a pail of small stones."

"But where were springs and pendulums?" gasped the astonished boy.

"Springs came a good deal later. Even pendulums were not introduced in
any practical form until 1657. Up to that time a balance did the work.
The advent of the pendulum, invented probably by Christian Huygens, a
Dutch mathematician, opened up no end of complications for the early
clockmakers. In the first place they could not decide where to put this
new article. Some placed the pendulum at the front of their clock,
letting it dangle down across the face; others tried to conceal it by
hanging it outside the back. Still others made a dial that would project
enough at either side to cover it up.

"Nor did the novel innovation of the pendulum do much good at first,
although theoretically makers of clocks conceded pendulums to be a
scientific advance over older methods. Of course the theory of the
pendulum had been for a long time in the minds of many thoughtful
persons. Galileo had seized on its principle when observing the swinging
of lanterns in the church at Pisa, and had written a scientific treatise
on it. But to get an idea is one thing and to apply it is quite another.
Pendulums were very complicated mechanisms. In the first place the
length of the pendulum decides, you see, the rate of the clock's
vibration; a short one resulting in a quick, nervous tick; and a long
one in a slow, quiet one. Therefore pendulums meant more even vibration
and more accurate time-keeping, and it was just when makers were
rejoicing over these advantages that it was discovered the temperature
of the place in which a clock stood affected the rod the bob hung on and
threw the whole timepiece out of adjustment. Here was a pretty