1ed, the water put therein would be more preſſed and crowded.
* And as is at
large demonſtrated
by that moſt excel
lent and lonour
able perſonage Mr.
Botle in the indu
ſtrious experiment
of his Pneumatical
Engine.
large demonſtrated
by that moſt excel
lent and lonour
able perſonage Mr.
Botle in the indu
ſtrious experiment
of his Pneumatical
Engine.
And therefore, in our caſe, according to our principles we will
ſay, that the water of that Stream paſseth all under the ſaid
Bridge Quattro-Capi, for that being there moſt ſwift, it ought of
conſequence to be leſs in meaſure.
ſay, that the water of that Stream paſseth all under the ſaid
Bridge Quattro-Capi, for that being there moſt ſwift, it ought of
conſequence to be leſs in meaſure.
And here one may ſee, into how many errours a man may run
through ignorance of a true and real Principle, which once known
and well underſtood, takes away all miſts of doubting, and ea
ſily reſolveth all difficulties.
through ignorance of a true and real Principle, which once known
and well underſtood, takes away all miſts of doubting, and ea
ſily reſolveth all difficulties.
COROLLARIE. XII.
Through the ſame inadvertency of not regarding the variation
of velocity in the ſame Current, therea re committed by Ingi
neers and Learned men, errours of very great moment (and I
could thereof produce examples, but for good reaſons I paſs
them over in ſilence) when they think, and propoſe, by deriving
new Channels from great Rivers, to diminiſh the meaſure of the
water in the River, and to diminiſh it proportionally, according
to the meaſure of the Water which they make to paſs through
the Channel, as making v.g a Channel fifty foot broad, in which
the derived water is to run waſte, ten foot deep, they think they
have diminiſhed the meaſure of the Water in the River five hun
dred feet, which thing doth not indeed ſo fall out; and the rea
ſon is plain; for that the Chanel being derived, the reſt of the
main River, diminiſheth in velocity, and therefore retains a grea
ter meaſure than it had at firſt before the derivation of the Cha
nel; and moreover, if the Chanel being derived, it ſhall not
conſerve the ſame velocity which it had at firſt in the main Ri
ver, but ſhall diminiſh it, it will be neceſſary, that it hath a grea
ter meaſure than it had before in the River; and therefore
to accompt aright, there ſhall not be ſo much water derived into
the Channel, as ſhall diminiſh the River, according to the quanti
ty of the water in the Channel, as is pretended.
of velocity in the ſame Current, therea re committed by Ingi
neers and Learned men, errours of very great moment (and I
could thereof produce examples, but for good reaſons I paſs
them over in ſilence) when they think, and propoſe, by deriving
new Channels from great Rivers, to diminiſh the meaſure of the
water in the River, and to diminiſh it proportionally, according
to the meaſure of the Water which they make to paſs through
the Channel, as making v.g a Channel fifty foot broad, in which
the derived water is to run waſte, ten foot deep, they think they
have diminiſhed the meaſure of the Water in the River five hun
dred feet, which thing doth not indeed ſo fall out; and the rea
ſon is plain; for that the Chanel being derived, the reſt of the
main River, diminiſheth in velocity, and therefore retains a grea
ter meaſure than it had at firſt before the derivation of the Cha
nel; and moreover, if the Chanel being derived, it ſhall not
conſerve the ſame velocity which it had at firſt in the main Ri
ver, but ſhall diminiſh it, it will be neceſſary, that it hath a grea
ter meaſure than it had before in the River; and therefore
to accompt aright, there ſhall not be ſo much water derived into
the Channel, as ſhall diminiſh the River, according to the quanti
ty of the water in the Channel, as is pretended.
COROLLARIE XIII.
This ſame conſideration giveth me occaſion to diſcover a moſt
ordinary errour, obſerved by me in the buſineſſe of the wa
ter of Ferara, when I was in thoſe parts, in ſervice of the moſt
Reverend and Illuſtrious Monfignor Corſini; the ſublime wit of
whom hath been a very great help to me in theſe contemplations;
its very true, I have been much perplexed, whether I ſhould
commit this particular to paper, or paſſe it over in ſilence, for
that I have ever doubted, that the opinion ſo common and
ordinary errour, obſerved by me in the buſineſſe of the wa
ter of Ferara, when I was in thoſe parts, in ſervice of the moſt
Reverend and Illuſtrious Monfignor Corſini; the ſublime wit of
whom hath been a very great help to me in theſe contemplations;
its very true, I have been much perplexed, whether I ſhould
commit this particular to paper, or paſſe it over in ſilence, for
that I have ever doubted, that the opinion ſo common and