with
it. In the first place they noticed that when the vessel was full the
greater pressure of water caused it to drip much faster than when there
was not much in it. This they had not considered before, and the
discovery forced them to attempt to improve it. This they did by
concocting a sort of double jar. In the lower one there was a float that
rose as the container filled; and since the top one was constantly
replenished, it kept the pressure in the bottom one uniform."

"The best yet!"

"Much the best. In fact it was a stride ahead from several standpoints,
for although it could not really be termed a machine it nevertheless was
a device that did for man something he would otherwise have had to do
for himself, which is the aim of all machinery. In just that proportion
he moved toward a civilization where artificial methods relieved him of
his labor. Thus he advanced quite a distance from that primitive
condition when he did everything with his hands toward his next state of
fashioning tools that would do what he wished to do better and quicker;
here was something which worked independently of him."

"Why, so it was! I never thought before that man passed through those
three stages," ejaculated Christopher with pleasure; "it makes our old
forefathers twice as interesting, doesn't it?"

"Three times as interesting," the Scotchman laughingly responded. "Facts
make very delightful stories, if you fasten them together. Scattered,
unrelated information is both dry and worthless. It is only when linked
up in the chain of history that it becomes interesting and valuable."

"The trouble with me is I never know where the things I learn belong,"
observed the lad soberly. "It's like fitting pieces into a puzzle when
you've no notion what picture you are making."

"I know, sonny," returned the old man with sympathy. "But do not imagine
you are the only one who is not always able to put in the proper place
the scraps of knowledge in his possession. Many an older person has
wondered what part his learning had in the gigantic total of the ages.
World history is conceived on a pretty big scale, you see. But that all
we glean is somehow linked up with the rest, you may be very sure.
Certainly this clepsydra was."

"It's easy enough to see that _afterward_," asserted Christopher. "And
so the Greeks managed to fix up their water clock to their satisfaction,
after all."

"Alas, not wholly to their satisfaction," was the answer