Alberti, Leone Battista
,
Architecture
,
1755
Text
Text Image
Image
XML
Thumbnail overview
Document information
None
Concordance
Figures
Thumbnails
page
|<
<
of 320
>
>|
<
archimedes
>
<
text
>
<
body
>
<
chap
>
<
p
type
="
main
">
<
s
>
<
pb
xlink:href
="
003/01/309.jpg
"
pagenum
="
229
"/>
the ſloweſt Current will be the moſt laſting:
<
lb
/>
Which may be ſomewhat illuſtrated by the
<
lb
/>
Compariſon of a Man that deſcends from a
<
lb
/>
ſteep Hill, and who comes down not direct
<
lb
/>
and as faſt as he can, but fetching different
<
lb
/>
Compaſſes about the Sides, ſometimes to the
<
lb
/>
right Hand, and ſometimes to the Left. </
s
>
<
s
>The
<
lb
/>
Rapidity of the Stream proceeds from the Steep
<
lb
/>
neſs of the Channel. </
s
>
<
s
>A Current either too
<
lb
/>
ſwift or too ſlow, is inconvenient. </
s
>
<
s
>The for
<
lb
/>
mer demoliſhes the Banks; the latter produ
<
lb
/>
ces Weeds, and is eaſily frozen. </
s
>
<
s
>Making the
<
lb
/>
River narrower may perhaps force the Water
<
lb
/>
to riſe higher, and another Way to make it
<
lb
/>
deeper is digging the Channel, lower. </
s
>
<
s
>Deep
<
lb
/>
ening the Channel, removing Impediments,
<
lb
/>
and clearing the River are all done by the
<
lb
/>
ſame Methods and for the ſame Purpoſes,
<
lb
/>
whereof we ſhall ſpeak preſently: But deepen
<
lb
/>
ing the Bottom of a River will be in vain, un
<
lb
/>
leſs we go on to do it quite away to the Sea,
<
lb
/>
in order to give the Stream its due Slope all
<
lb
/>
the Way.</
s
>
</
p
>
<
p
type
="
head
">
<
s
>CHAP. XI.</
s
>
</
p
>
<
p
type
="
head
">
<
s
>
<
emph
type
="
italics
"/>
Of Canals; how they are to be kept well ſupplied with Water, and the Uſes
<
lb
/>
of them not obſtructed.
<
emph.end
type
="
italics
"/>
</
s
>
</
p
>
<
p
type
="
main
">
<
s
>We now proceed to ſpeak of Canals.
<
lb
/>
</
s
>
<
s
>What we are to provide for in theſe,
<
lb
/>
is that they be well ſupplied with Water, and
<
lb
/>
that the Uſes for which they are intended be
<
lb
/>
not obſtructed. </
s
>
<
s
>There are two Ways of prevent
<
lb
/>
ing their failing. </
s
>
<
s
>The firſt is to have a large
<
lb
/>
Quantity of Water conſtantly running into them
<
lb
/>
from ſome other Stream; the ſecond is to con
<
lb
/>
trive that they keep what does come into them
<
lb
/>
as long as can be. </
s
>
<
s
>The Water is to be brought
<
lb
/>
into Canals in the manner above ſet down: and
<
lb
/>
our Diligence muſt prevent their Uſes from be
<
lb
/>
ing obſtructed, by often cleaning them, and
<
lb
/>
removing whatever Incumbrances may be
<
lb
/>
brought into them. </
s
>
<
s
>A Canal is ſaid to be a
<
lb
/>
ſleeping River; and it ſhould therefore have
<
lb
/>
all the ſame Properties which a River has, and
<
lb
/>
eſpecially its Bottom and Sides ſhould be per
<
lb
/>
fectly ſound, that the Water may neither be
<
lb
/>
ſucked up, nor run out at any Cracks. </
s
>
<
s
>It
<
lb
/>
ſhould be more deep than broad, as well for the
<
lb
/>
better carrying off all Sorts of Veſſels, as that it
<
lb
/>
may be leſs exhauſted by the Sun and breed the
<
lb
/>
fewer Weeds. </
s
>
<
s
>A great many Canals were cut
<
lb
/>
from the
<
emph
type
="
italics
"/>
Euphrates
<
emph.end
type
="
italics
"/>
to the
<
emph
type
="
italics
"/>
Tygris,
<
emph.end
type
="
italics
"/>
becauſe the
<
lb
/>
Channel of the former lay higher than that of
<
lb
/>
the Latter.
<
emph
type
="
italics
"/>
Lombardy
<
emph.end
type
="
italics
"/>
lying between the
<
emph
type
="
italics
"/>
Po
<
emph.end
type
="
italics
"/>
<
lb
/>
and the
<
emph
type
="
italics
"/>
Adige,
<
emph.end
type
="
italics
"/>
is every where navigable by
<
lb
/>
Canals; an Advantage which it gains by ly
<
lb
/>
ing all upon a Flat.
<
emph
type
="
italics
"/>
Diodorus
<
emph.end
type
="
italics
"/>
tells us, that
<
lb
/>
when
<
emph
type
="
italics
"/>
Ptolomey
<
emph.end
type
="
italics
"/>
went out of the Mouth of the
<
lb
/>
<
emph
type
="
italics
"/>
Nile,
<
emph.end
type
="
italics
"/>
he opened a Canal on Purpoſe, and had
<
lb
/>
it ſtopp'd up as ſoon as he was got through it.
<
lb
/>
</
s
>
<
s
>The Remedies for the ſeveral Faults of either
<
lb
/>
Canals or Rivers are confining, clearing and
<
lb
/>
ſtopping them. </
s
>
<
s
>Rivers are confined by arti
<
lb
/>
ficial Banks. </
s
>
<
s
>The Line of ſuch Banks ſhould
<
lb
/>
not reſtrain the River at once, but by degrees,
<
lb
/>
by means of an eaſy Slope. </
s
>
<
s
>When you would
<
lb
/>
ſet it at Liberty again from a narrow Channel
<
lb
/>
into a wider Breadth, you muſt obſerve the
<
lb
/>
ſame Method, not let it out at once, but gently,
<
lb
/>
leſt upon too ſudden an Enlargment it does
<
lb
/>
Miſchief by Eddies and Whirlpools. </
s
>
<
s
>The River
<
lb
/>
<
emph
type
="
italics
"/>
Melas
<
emph.end
type
="
italics
"/>
uſed of old to run into the
<
emph
type
="
italics
"/>
Euphrates;
<
emph.end
type
="
italics
"/>
<
lb
/>
but King
<
emph
type
="
italics
"/>
Artanatrix,
<
emph.end
type
="
italics
"/>
perhaps out of a Deſire
<
lb
/>
to make his Name famous, ſtopp'd it up and
<
lb
/>
overſlowed the Country all round: but ſoon
<
lb
/>
afterwards the Waters return'd with ſuch Ed
<
lb
/>
dies and ſo much Fury that they tore up all
<
lb
/>
that reſiſted them, waſhed away a great many
<
lb
/>
Eſtates, and laid Waſte a great Part of
<
emph
type
="
italics
"/>
Phrygia
<
emph.end
type
="
italics
"/>
<
lb
/>
and
<
emph
type
="
italics
"/>
Galatia.
<
emph.end
type
="
italics
"/>
</
s
>
<
s
> The
<
emph
type
="
italics
"/>
Roman Senate
<
emph.end
type
="
italics
"/>
fined the
<
lb
/>
King for this audacious Attempt, in thirty Ta
<
lb
/>
lents. </
s
>
<
s
>Nor is it foreign to our Purpoſe juſt to
<
lb
/>
mention what we read of
<
emph
type
="
italics
"/>
Iphicrates
<
emph.end
type
="
italics
"/>
the
<
emph
type
="
italics
"/>
A
<
lb
/>
thenian,
<
emph.end
type
="
italics
"/>
that when he was beſieging
<
emph
type
="
italics
"/>
Stymphalus
<
emph.end
type
="
italics
"/>
<
lb
/>
in
<
emph
type
="
italics
"/>
Arcadia
<
emph.end
type
="
italics
"/>
he attempted with a vaſt Quantity
<
lb
/>
of Spunge to ſtop up the River
<
emph
type
="
italics
"/>
Eraſinus
<
emph.end
type
="
italics
"/>
which
<
lb
/>
enters into the Hill and riſes up again in the
<
lb
/>
Country of
<
emph
type
="
italics
"/>
Arges;
<
emph.end
type
="
italics
"/>
but by the Admonition of
<
lb
/>
<
emph
type
="
italics
"/>
Jupiter
<
emph.end
type
="
italics
"/>
he laid aſide the Deſign. </
s
>
<
s
>I adviſe
<
lb
/>
therefore, that your artificial Bank be made as
<
lb
/>
ſtrong as poſſible. </
s
>
<
s
>This Strength muſt be
<
lb
/>
owing to the Solidity of your Materials, your
<
lb
/>
Method of putting them together, and the
<
lb
/>
Breadth of the whole Work. </
s
>
<
s
>Where it is ne
<
lb
/>
ceſſary that the Water ſhould run over this
<
lb
/>
Bank, do not let the Outſide of it be a Per
<
lb
/>
pendicular, but fall in an eaſy Slope, that the
<
lb
/>
Water may run down it eaſily and not form
<
lb
/>
any Eddies. </
s
>
<
s
>If in its Fall it begins to dig up </
s
>
</
p
>
</
chap
>
</
body
>
</
text
>
</
archimedes
>