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storage are now reduced. To obviate this disadvantage it was 
necessary to put up engines of 200 and 100 horse-power at 
Sparndam and Halfwege, and widen the channel leading to 
the Katwyck sluice. Another work preliminary to the drain- 
age was the navigable canal (Ringvart), adapted to vessels 
drawing 8 feet of water, which previously traversed the lake; 
this canal had a total length of 36 miles, and width of 146 
feet, the inner bank being in fact the dyke surrounding the 
lake, and cutting off the waters which otherwise would flow in 
during and after the laying dry of the bed. 
All preliminary works being thus completed, the raising of 
the waters up to the level of the sea was effected by three engines 
of 350 horse-power each, on the Cornish principle, constructed 
by Harvey and Co., at Hayle foundry, after designs by Messrs. 
Gibbs and Deane; the cylinders were 12 feet diameter and 10 
feet stroke. From numerous and unforeseen causes of delay 
they were thirty-nine months in raising the water; and instead 
of 800000000 of tons of water, the computed contents of the 
lake, they actually raised 1100000000 tons. These engines will 
be required for all time to keep dry the land they may be said 
to have created, not, however, by that continuous working by 
which the first operation has been performed, but by throwing 
off extraordinary rain-falls before they have injuriously affected 
the land. Eight inches of rain-fall and infiltration per month 
is the maximum quantity that long-continued observations 
lead them to expect, and this can be raised in about twenty-five 
working days by the 1150 horse-power of the three engines. 
The original estimated cost of all the works of the drainage 
was £687500; the actual expenditure, £827200. The sale of 
the land has realized about £400000, and the land tax, 7s. 4d. 
per acre, being capitalized, would yield a like sum; nor must 
we omit the saving of £5000 per annum, formerly expended in 
guarding the banks of the lake from destruction during storms, 
but which now of course ceases. 
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