1its Waters in its own Chanel, without diſcharging them into Ty
ber, or elſe would have ingorged and ſwallowed (if I may ſo ſay)
ſome of the water of Tyber; and in this caſe, at the time of In
undation, leſſe abundance of water would have come to Rome,
and yet nevertheleſſe the meaſure of that River would have been
increaſed.
ber, or elſe would have ingorged and ſwallowed (if I may ſo ſay)
ſome of the water of Tyber; and in this caſe, at the time of In
undation, leſſe abundance of water would have come to Rome,
and yet nevertheleſſe the meaſure of that River would have been
increaſed.
Fifthly, Fontana deceiveth himſelf, when he concludeth, that
to remove the Inundation from Rome, it would be neceſſary to
make two other Chanels of Rivers, that were as large as that,
which is the preſent one, and that leſs would not ſuffice, which,
I ſay, is a fallacy: and to convince him eaſily of his errour, it
ſufficeth to ſay, that all the Streams being paſſed under the Bridge
Quattro-Capi, as he himſelf atteſts, a Channel would ſuffice on
ly of the capacity of the ſaid Bridge, provided that the water
there might run with the ſame velocity, as it did under the Bridge
at the time of Inundation; and on the contrary, twenty Cur
rents of capacity equal to the preſent one, would not ſuffice, if
the water ſhould run with twenty times leſs velocity, than it made
at the time of the Inundation.
to remove the Inundation from Rome, it would be neceſſary to
make two other Chanels of Rivers, that were as large as that,
which is the preſent one, and that leſs would not ſuffice, which,
I ſay, is a fallacy: and to convince him eaſily of his errour, it
ſufficeth to ſay, that all the Streams being paſſed under the Bridge
Quattro-Capi, as he himſelf atteſts, a Channel would ſuffice on
ly of the capacity of the ſaid Bridge, provided that the water
there might run with the ſame velocity, as it did under the Bridge
at the time of Inundation; and on the contrary, twenty Cur
rents of capacity equal to the preſent one, would not ſuffice, if
the water ſhould run with twenty times leſs velocity, than it made
at the time of the Inundation.
Sixthly, to me it ſeemeth a great weakneſſe to ſay, that there
ſhould paſſe under the Bridge Quattro-Capi, an hundred fifty one
ells of water compreſſed; for that I do not underſtand that wa
ter is like Cotton or Wool, which matters may be preſt and trod,
as it happeneth alſo to the air, which receiveth compreſſion in
ſuch ſort, that after that in ſome certain place a quantity of air
ſhall be reduced to its natural conſtitution; and having taken up
all the ſaid place, yet nevertheleſſe compreſſing the firſt Air
with force and violence, it is reduced into far leſs room, and will
admit four or ſix times as much air, as before, as is experimen
tally ^{*} ſeen in the Wind-Gun, invented in our dayes by M. Vin,
cenzo Vincenti of Vrbin, which property of the Air of admit
ting condenſation, is alſo ſeen in the portable Fountains of the
ſame M. Vincenzo: which Fountains ſpirt the Water on high,
by force of the Air compreſſed, which whilſt it ſeeks to reduce
its ſelf to its natural conſtitution, in the dilation cauſeth that vi
olence. But the water can never, for any thing I know, crowd,
or preſs ſo, as that if before the compreſſion it held or poſſeſt a
place, being in its natural conſtitution, I believe not, I ſay, that it
is poſſible, by preſſing and crowding to make it poſſeſs leſs room,
for if it were poſſible to compreſs the Water, and make it to oc
cupy a leſs place, it would thence follow, that two Veſſels of e
qual meaſure, but of unequal height, ſhould be of unequal capa
city, and that ſhould hold more water which was higher; alſo a
Cylinder, or other Veſſel more high than broad, would containe
more water erected, than being laid along; for that being erect
ſhould paſſe under the Bridge Quattro-Capi, an hundred fifty one
ells of water compreſſed; for that I do not underſtand that wa
ter is like Cotton or Wool, which matters may be preſt and trod,
as it happeneth alſo to the air, which receiveth compreſſion in
ſuch ſort, that after that in ſome certain place a quantity of air
ſhall be reduced to its natural conſtitution; and having taken up
all the ſaid place, yet nevertheleſſe compreſſing the firſt Air
with force and violence, it is reduced into far leſs room, and will
admit four or ſix times as much air, as before, as is experimen
tally ^{*} ſeen in the Wind-Gun, invented in our dayes by M. Vin,
cenzo Vincenti of Vrbin, which property of the Air of admit
ting condenſation, is alſo ſeen in the portable Fountains of the
ſame M. Vincenzo: which Fountains ſpirt the Water on high,
by force of the Air compreſſed, which whilſt it ſeeks to reduce
its ſelf to its natural conſtitution, in the dilation cauſeth that vi
olence. But the water can never, for any thing I know, crowd,
or preſs ſo, as that if before the compreſſion it held or poſſeſt a
place, being in its natural conſtitution, I believe not, I ſay, that it
is poſſible, by preſſing and crowding to make it poſſeſs leſs room,
for if it were poſſible to compreſs the Water, and make it to oc
cupy a leſs place, it would thence follow, that two Veſſels of e
qual meaſure, but of unequal height, ſhould be of unequal capa
city, and that ſhould hold more water which was higher; alſo a
Cylinder, or other Veſſel more high than broad, would containe
more water erected, than being laid along; for that being erect