readers take lessons in athletics.
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THE LOCK OF THE DORTMUND-EMS CANAL AT HENRICHENBURG.
The Dortmund-Ems Canal, destined to connect the heart of German
industry with the sea, was formally dedicated on April 1, and
partially opened to commerce. After its completion, German coal will
be transported to the harbors of the Ems at the same cost as the
English coal which has hitherto forced back the treasures of our soil;
our black diamonds will then be sold in the markets of the world, and
the Kaiser Wilhelm Canal will enable the western part of the empire to
exchange its coal and iron for the grain and wood of the East.
Many difficulties were encountered in cutting the canal, owing partly
to the vast network of railroads in the coal region of Westphalia, but
chiefly due to the insufficiency of moisture in the highlands, the
latter not containing enough water to supply the many necessary
sluices, at which it could be easily foreseen considerable traffic
would occur.
[Illustration: THE LOCK OF THE DORTMUND-EMS CANAL AT HENRICHENBURG.]
For the modern engineer there are, however, no insurmountable
obstacles. Instead of a line of ordinary locks, a single structure was
erected sufficient for the needs of the entire region. This lock is
situated at Henrichenburg, near Dortmund, and our illustration
pictures it with its lock-chamber half raised.
The lock, which serves to overcome a difference in level of fifty-nine
feet, raises vessels of 1,000 tons capacity with a velocity of 0.3 to
0.7 foot per second, and has been constructed after a new and
astonishingly simple system.
The lock chamber, designed for the reception of the various vessels,
is 229.60 feet in length and 28.864 feet in breadth and normally
contains 8.2 feet of water. Under the sluice in a line with the long
axis are five wells filled with water in which cylindrical floats are
placed, connected to the bottom of the chamber by means of iron
trellis-work. The floats are placed so deeply that, in their highest
position, their upper edges are always submerged; they are, moreover,
of such size that by means of their upward impulsion the chamber is
held in equilibrium. Irrespective of the small differences of pressure
which arise from the varying immersion of the framework, the lock will
in all positions be in equilibrium. Since a vessel which enters the
lock displaces a volume of water whose weight is equal
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