y-three miles in circumference, and containing forty-five
thousand acres. Three huge systems of pumps were erected, to be worked
by steam, and the task of discharging an average depth of thirteen feet
of water was begun. After four years' pumping, the lake was dried up,
and the land was sold at the rate of about eighty-five dollars an acre.
The machinery is still required to keep the water down. One engine works
eleven pumps, with a lift of thirteen feet, discharging sixty-three tons
of water at a stroke.

The travellers took their places in the train, and in a few minutes were
conveyed over the causeways into Amsterdam, in season for the two
o'clock dinner.

CHAPTER XX.

ADIEU TO HOLLAND AND PROFESSOR HAMBLIN.

After dinner the party, in charge of a couple of the city officials, who
had given them a welcome, went to the Palace, the noblest building in
Amsterdam. It rests upon nearly fourteen thousand piles, driven seventy
feet through the mud to "hard pan." During the reign of King Louis, it
was his residence, and the other sovereigns of Holland used it when they
visited the city. Its remarkable feature is an imposing hall, one
hundred and twenty feet long, fifty-seven feet wide, and one hundred
feet high. The interior is lined with Italian marble, and adorned with
works of art.

"Young gentlemen," said Mr. Mapps, taking position in this great hall,
"Amsterdam contains a population of two hundred and sixty-eight
thousand. In shape, it forms rather more than the plane of a half
circle, the circumference being composed of the walls of the city,
outside of which is an immense canal. Inside of the walls there are four
principal canals, extending nearly around the city. Take the transverse
section of the trunk of a chestnut tree, divide it, with the grain of
the wood, into two equal parts, and the top of one of them will give you
the plane of the half circle. The layers of the log, formed by each
year's growth, would indicate the canals and the intervening spaces
covered with buildings. The heart of the city, however, is irregular.

"Each of these canals is situated in the centre of a broad street. The
Keizers Gracht, or Canal, is one hundred and forty feet wide. They are
not circular, but form the sides of an irregular decagon. Other canals
intersect the principal ones, so that all parts of the city may be
visited in boats or vessels. The River Amstel flows through the town by
a winding course; and Amsterdam