the &longs;lowe&longs;t Current will be the mo&longs;t la&longs;ting: <lb/>
Which may be &longs;omewhat illu&longs;trated by the <lb/>
Compari&longs;on of a Man that de&longs;cends from a <lb/>
&longs;teep Hill, and who comes down not direct <lb/>
and as fa&longs;t as he can, but fetching different <lb/>
Compa&longs;&longs;es about the Sides, &longs;ometimes to the <lb/>
right Hand, and &longs;ometimes to the Left. </s> <s>The <lb/>
Rapidity of the Stream proceeds from the Steep<lb/>
ne&longs;s of the Channel. </s> <s>A Current either too <lb/>
&longs;wift or too &longs;low, is inconvenient. </s> <s>The for<lb/>
mer demoli&longs;hes the Banks; the latter produ<lb/>
ces Weeds, and is ea&longs;ily frozen. </s> <s>Making the <lb/>
River narrower may perhaps force the Water <lb/>
to ri&longs;e 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/>
&longs;ame Methods and for the &longs;ame Purpo&longs;es, <lb/>
whereof we &longs;hall &longs;peak pre&longs;ently: But deepen<lb/>
ing the Bottom of a River will be in vain, un<lb/>
le&longs;s 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>

 <s>CHAP. XI.</s>

 <s><emph type="italics"/>Of Canals; how they are to be kept well &longs;upplied with Water, and the U&longs;es <lb/>
of them not ob&longs;tructed.<emph.end type="italics"/></s>

 <s>We now proceed to &longs;peak of Canals. <lb/>
</s> <s>What we are to provide for in the&longs;e, <lb/>
is that they be well &longs;upplied with Water, and <lb/>
that the U&longs;es for which they are intended be <lb/>
not ob&longs;tructed. </s> <s>There are two Ways of prevent<lb/>
ing their failing. </s> <s>The fir&longs;t is to have a large <lb/>
Quantity of Water con&longs;tantly running into them <lb/>
from &longs;ome other Stream; the &longs;econd 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 &longs;et down: and <lb/>
our Diligence mu&longs;t prevent their U&longs;es from be<lb/>
ing ob&longs;tructed, by often cleaning them, and <lb/>
removing whatever Incumbrances may be <lb/>
brought into them. </s> <s>A Canal is &longs;aid to be a <lb/>
&longs;leeping River; and it &longs;hould therefore have <lb/>
all the &longs;ame Properties which a River has, and <lb/>
e&longs;pecially its Bottom and Sides &longs;hould be per<lb/>
fectly &longs;ound, that the Water may neither be <lb/>
&longs;ucked up, nor run out at any Cracks. </s> <s>It <lb/>
&longs;hould be more deep than broad, as well for the <lb/>
better carrying off all Sorts of Ve&longs;&longs;els, as that it <lb/>
may be le&longs;s exhau&longs;ted 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"/> becau&longs;e 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 Purpo&longs;e, and had <lb/>
it &longs;topp'd up as &longs;oon as he was got through it. <lb/>
</s> <s>The Remedies for the &longs;everal Faults of either <lb/>
Canals or Rivers are confining, clearing and <lb/>
&longs;topping them. </s> <s>Rivers are confined by arti<lb/>
ficial Banks. </s> <s>The Line of &longs;uch Banks &longs;hould <lb/>
not re&longs;train the River at once, but by degrees, <lb/>
by means of an ea&longs;y Slope. </s> <s>When you would <lb/>
&longs;et it at Liberty again from a narrow Channel <lb/>
into a wider Breadth, you mu&longs;t ob&longs;erve the <lb/>
&longs;ame Method, not let it out at once, but gently, <lb/>
le&longs;t upon too &longs;udden an Enlargment it does <lb/>
Mi&longs;chief by Eddies and Whirlpools. </s> <s>The River <lb/>
<emph type="italics"/>Melas<emph.end type="italics"/> u&longs;ed 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 De&longs;ire <lb/>
to make his Name famous, &longs;topp'd it up and <lb/>
over&longs;lowed the Country all round: but &longs;oon <lb/>
afterwards the Waters return'd with &longs;uch Ed<lb/>
dies and &longs;o much Fury that they tore up all <lb/>
that re&longs;i&longs;ted them, wa&longs;hed away a great many <lb/>
E&longs;tates, and laid Wa&longs;te 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 Purpo&longs;e ju&longs;t 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 be&longs;ieging <emph type="italics"/>Stymphalus<emph.end type="italics"/><lb/>
in <emph type="italics"/>Arcadia<emph.end type="italics"/> he attempted with a va&longs;t Quantity <lb/>
of Spunge to &longs;top up the River <emph type="italics"/>Era&longs;inus<emph.end type="italics"/> which <lb/>
enters into the Hill and ri&longs;es 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 a&longs;ide the De&longs;ign. </s> <s>I advi&longs;e <lb/>
therefore, that your artificial Bank be made as <lb/>
&longs;trong as po&longs;&longs;ible. </s> <s>This Strength mu&longs;t 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/>
ce&longs;&longs;ary that the Water &longs;hould run over this <lb/>
Bank, do not let the Out&longs;ide of it be a Per<lb/>
pendicular, but fall in an ea&longs;y Slope, that the <lb/>
Water may run down it ea&longs;ily and not form <lb/>
any Eddies. </s> <s>If in its Fall it begins to dig up