And in this manner all thoſe Prodigies vaniſh that are raiſed
with ſo much fear from the enterance of the Water of Reno
ſwelled into Po, when it is high, to which there needeth no other
anſwer; yet nevertheleſſe we do not take that quantity of Wa
ter, that is carried by Reno, and by Panaro, to be ſo great as is affir
med: For that P. D. Benedetto Caſtelli hath no leſſe accutely
than accurately obſerved the meaſures of this kind, noting that
the breadth and depth of a River is not enough to reſolve the
queſtion truly, but that there is reſpect to be had to the velocity
of the Waters, and the term of time, things hitherto not conſi
dered by the Skilful in theſe affairs; and therefore they are not
able to ſay what quantity of Waters the ſaid Rivers carry, nor
to conclude of the riſings that will follow thereupon. Nay, it
is moſt certain, that if all the Rivers that fall into Po, which are
above thirty, ſhould riſe at the rate that theſe compute Reno to
do, an hundred feet of Banks would not ſuffice, and yet they
have far fewer: So that this confirmes the Rule of R. P. D. Bene
detto, namely, that the proportion of the height of the Water
of Reno in Reno to the height of the Water of Reno in Po, is
compounded of the proportion of the breadth of the Chanel of
Po to that of Reno, and of the velocity of the Water of Reno
in Po to the velccity of the Water of Reno in Reno; a manifeſt
argument that there cannot in it, by this new augmentation of
Waters follow any alteration that neceſſitates the raiſing of its
Banks, as appeareth by the example of Panaro, which hath been
ſo far from ſwelling Po, that it hath rather aſſwaged it, for it hath
carried away many Shelfs and many Iſlets that had grown in its
Bed, for want of Waters ſufficient to bear away the matter of
Land-floods in ſo broad a Chanel; and as is learnt by the trial
made by us in Panaro with the Water of Burana; for erecting
in the River ſtanding marks, and ſhutting the ſaid Sluice, we could
ſee no ſenſible abatement, nor much leſs after we had opened it
ſenſible increaſment; by which we judge that the ſame is to ſuc
ceed to Po, by letting in of Reno, Burana having greater pro
portion to Panaro than Reno to Po, conſidering the ſtate of thoſe
Rivers in which the Obſervation was made. So that there is no
longer any occaſion for thoſe great raiſings of Banks, and the
danger of the ruptures as well of Reno as of Po do vaniſh, as al
ſo the fear leſt that the Sluices which empty into Po ſhould re
ceive obſtruction: which if they ſhould, yet it would be over in
a few hours. And as to the Breaches of Panaro which happened
in 1623. I know not why, ſeeing that it is confeſſed that the Po
was not, at that time, at its height, one ſhould rather charge it
with ſo much fear from the enterance of the Water of Reno
ſwelled into Po, when it is high, to which there needeth no other
anſwer; yet nevertheleſſe we do not take that quantity of Wa
ter, that is carried by Reno, and by Panaro, to be ſo great as is affir
med: For that P. D. Benedetto Caſtelli hath no leſſe accutely
than accurately obſerved the meaſures of this kind, noting that
the breadth and depth of a River is not enough to reſolve the
queſtion truly, but that there is reſpect to be had to the velocity
of the Waters, and the term of time, things hitherto not conſi
dered by the Skilful in theſe affairs; and therefore they are not
able to ſay what quantity of Waters the ſaid Rivers carry, nor
to conclude of the riſings that will follow thereupon. Nay, it
is moſt certain, that if all the Rivers that fall into Po, which are
above thirty, ſhould riſe at the rate that theſe compute Reno to
do, an hundred feet of Banks would not ſuffice, and yet they
have far fewer: So that this confirmes the Rule of R. P. D. Bene
detto, namely, that the proportion of the height of the Water
of Reno in Reno to the height of the Water of Reno in Po, is
compounded of the proportion of the breadth of the Chanel of
Po to that of Reno, and of the velocity of the Water of Reno
in Po to the velccity of the Water of Reno in Reno; a manifeſt
argument that there cannot in it, by this new augmentation of
Waters follow any alteration that neceſſitates the raiſing of its
Banks, as appeareth by the example of Panaro, which hath been
ſo far from ſwelling Po, that it hath rather aſſwaged it, for it hath
carried away many Shelfs and many Iſlets that had grown in its
Bed, for want of Waters ſufficient to bear away the matter of
Land-floods in ſo broad a Chanel; and as is learnt by the trial
made by us in Panaro with the Water of Burana; for erecting
in the River ſtanding marks, and ſhutting the ſaid Sluice, we could
ſee no ſenſible abatement, nor much leſs after we had opened it
ſenſible increaſment; by which we judge that the ſame is to ſuc
ceed to Po, by letting in of Reno, Burana having greater pro
portion to Panaro than Reno to Po, conſidering the ſtate of thoſe
Rivers in which the Obſervation was made. So that there is no
longer any occaſion for thoſe great raiſings of Banks, and the
danger of the ruptures as well of Reno as of Po do vaniſh, as al
ſo the fear leſt that the Sluices which empty into Po ſhould re
ceive obſtruction: which if they ſhould, yet it would be over in
a few hours. And as to the Breaches of Panaro which happened
in 1623. I know not why, ſeeing that it is confeſſed that the Po
was not, at that time, at its height, one ſhould rather charge it