38
R.Berka
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Fig. 4: &) Simple levelling instrument from the 1st half of the 16th
century utilized for levelling the ponds in landscape
b) All—woden pond outlet gate (15th and 16th century)
A — pin of the outlet tube
—
B — cross
section
of the wooden outlet tube
c) Cross sections of pond dam
A — the first primitive construction
B
—
construction improved by Bohemian master builders
in the beginning of the 16th century — line ofsaturation
doesn't reach the heel of dam & therefore the construction
is maximally safe