45 
1877 .] The Port of Ymuiden. 
Two sections of the canal pass through dry land ; the one 
from the North Sea to Wijkermeer, at Valsen, 6540 yards 
long ; and the other across the peninsula of Beutzenhuisen, 
875 yards in length. The portion of the canal passing 
through the Wijkermeer has a length of 4779 yards, and 
that through the Western Ij one of 13,725 yards. 
The canal is formed with a bottom width of 88 feet 6 ins., 
and a surface width of 207 feet, and when finally completed 
it will be over 23 feet in depth. These dimensions continue 
throughout 22,966 yards in length of the canal, measured 
from the North Sea, after which the width gradually in- 
creases until it joins the “ diep ” near Amsterdam : here the 
dykes turn away from the canal, the northern one running 
in a straight line to Buikslooterham, and the southerly one 
in a curved line to Amsterdam. 
The, earth excavated from the land sections of the canal 
is conveyed in barges, and deposited on the muddy bottom 
of the lake to form dykes on either side, where it passes 
through the Wijkermeer and the Ij. These deposits are 
then covered with clay, and as soon as the bank appears 
above the surface of the water, and is formed, the slopes are 
protected from the wash of the waves with fascines. The 
canal channel is then dredged between the banks so formed, 
for which purpose steam dredgers are employed with self- 
acting discharging apparatus. This apparatus consists of a 
vertical cylinder fitted on to the steam dredger, into which 
the excavated mud is thrown. On the lower end of this 
cylinder a horizontal centrifugal pump-wheel, of about 
40 ins. in diameter, works, which is driven by the engine of 
the steam dredger, at a speed of 230 revolutions a minute, 
forcing the mud from the cylinder, in a semi-fluid state, into 
a floating tube, through which it is carried away. The 
floating tubes consist of wooden cylinders of about 50 feet 
in length and 15 inches in diameter, joined together by flex- 
ible leather couplings. These float on the surface of the 
water for distances of from 750 to 800 feet, the ends being 
carried through and sometimes over the previously-made 
sandy dykes, behind which a jet of muddy water is dis- 
charged, containing from 40 to 50 per cent of solid matter, 
which thus becomes deposited over a considerable surface. 
From 1200 to 1500 tons of sand is raised by one dredger, 
with a 20-horse power engine, per day. 
In order to connect the different navigation and drainage 
locks and sluices along the borders of the Ij with the main 
canal, several branch canals have been constructed, of 
varying sections, and having an aggregate length about 
