1the Vent, yet this benefit happens to be but temporary and for a
few hours: If the riſing of Po, and the dangers of breaking forth
were of ſhort duration, as it ordinarily befalleth in the overflow
ings of Torrents, in ſuch a caſe the profit of the Vent would be
of ſome eſteem: But becauſe the ſwellings of Po continue for
thirty, or ſometimes for forty dayes, therefore the gain which
reſults from the Vent proveth to be inconſiderable. It remain
eth now to conſider the notable harms which follow the ſaid
Sluice or Vent, that ſo reflection being made, and the profit and
the detriment compared, one may rightly judge, and chooſe that
which ſhall be moſt convenient. The firſt prejudice therefore
which ariſeth from this Vent or Sluice, is; That the Channels of
Ferara, Primaro, and Volana filling with Water, all thoſe parts
from Bondeno to the Sea ſide are allarmed and endangered
thereby. Secondly, The Waters of the Po of Primaro having
free ingreſſe into the upper Valleys, they fill them to the great
damage of the Fields adjacent, and obſtruct the courſe of the
ordinary Trenches in the ſame Valleys; inſomuch that all the
care, coſt, and labour about the draining, and freeing the upper
Valleys from Water, would alſo become vain and ineffectual.
Thirdly, I conſider that theſe Waters of the Po of Ferara being
paſſed downwards towards the Sea, at the time that the main Po
was in its greater excreſcences and heights, it is manifeſt by expe
rience, that when the great Po diminiſheth, then theſe Waters
paſſed by the Po of Ferara begin to retard in their courſe, and
finally come to turn the current upwards towards Stellata, reſting
firſt iu the intermediate time, almoſt fixed and ſtanding, and
therefore depoſing the muddineſſe, they fill up the Channel of
the River or Current of Ferara. Fourthly and laſtly, There
followeth from this ſame diverſion another notable damage, and
it is like to that which followeth the breaches made by Rivers;
near to which breaches in the lower parts, namely below the
breach, there is begot in the Channel of the River, a certain ridge
or ſhelf, that is, the bottom of the River is raiſed, as if ſufficiently
manifeſt by experience; and thus juſt in the ſame manner cutting
the Bank at Bondeno, there is at it were a breach made, from which
followeth the riſing in the lower parts of the main Po, being paſt
the mouth of Pamaro; which thing, how pernitious it is, let any one
judge that underſtandeth theſe matters. And therefore both for
the ſmall benefit, and ſo many harms that enſue from maintain
ing this diverſion, I ſhould think it were more ſound advice to
keep that Bank alwaies whole at Bondeno, or in any other conve
nient place, and not to permit that the Water of the Grand Po
ſhould ever come near to Ferara.
few hours: If the riſing of Po, and the dangers of breaking forth
were of ſhort duration, as it ordinarily befalleth in the overflow
ings of Torrents, in ſuch a caſe the profit of the Vent would be
of ſome eſteem: But becauſe the ſwellings of Po continue for
thirty, or ſometimes for forty dayes, therefore the gain which
reſults from the Vent proveth to be inconſiderable. It remain
eth now to conſider the notable harms which follow the ſaid
Sluice or Vent, that ſo reflection being made, and the profit and
the detriment compared, one may rightly judge, and chooſe that
which ſhall be moſt convenient. The firſt prejudice therefore
which ariſeth from this Vent or Sluice, is; That the Channels of
Ferara, Primaro, and Volana filling with Water, all thoſe parts
from Bondeno to the Sea ſide are allarmed and endangered
thereby. Secondly, The Waters of the Po of Primaro having
free ingreſſe into the upper Valleys, they fill them to the great
damage of the Fields adjacent, and obſtruct the courſe of the
ordinary Trenches in the ſame Valleys; inſomuch that all the
care, coſt, and labour about the draining, and freeing the upper
Valleys from Water, would alſo become vain and ineffectual.
Thirdly, I conſider that theſe Waters of the Po of Ferara being
paſſed downwards towards the Sea, at the time that the main Po
was in its greater excreſcences and heights, it is manifeſt by expe
rience, that when the great Po diminiſheth, then theſe Waters
paſſed by the Po of Ferara begin to retard in their courſe, and
finally come to turn the current upwards towards Stellata, reſting
firſt iu the intermediate time, almoſt fixed and ſtanding, and
therefore depoſing the muddineſſe, they fill up the Channel of
the River or Current of Ferara. Fourthly and laſtly, There
followeth from this ſame diverſion another notable damage, and
it is like to that which followeth the breaches made by Rivers;
near to which breaches in the lower parts, namely below the
breach, there is begot in the Channel of the River, a certain ridge
or ſhelf, that is, the bottom of the River is raiſed, as if ſufficiently
manifeſt by experience; and thus juſt in the ſame manner cutting
the Bank at Bondeno, there is at it were a breach made, from which
followeth the riſing in the lower parts of the main Po, being paſt
the mouth of Pamaro; which thing, how pernitious it is, let any one
judge that underſtandeth theſe matters. And therefore both for
the ſmall benefit, and ſo many harms that enſue from maintain
ing this diverſion, I ſhould think it were more ſound advice to
keep that Bank alwaies whole at Bondeno, or in any other conve
nient place, and not to permit that the Water of the Grand Po
ſhould ever come near to Ferara.