Constitutional Whig. [volume] (Richmond, Va.) 1824-1832, 1824-02-17

there two feeders taken from the river to be add
cd to the supply furnished by the Canagoharie one
of the boldest creeks ,of the Mohawk, and other
smaller tributaries.
In relation to the other division of 81 miles it was
originally supposed by the projectors of the work,
that dam feet high across the mouth of the Scho
harie and at the point where the line of the canal
passed it, raising its to level with the water
line of the canal, and thus afording not only full
feeder to the navigation, but considerable reser-
voir to maintain the supply, would be found sufici
ent for the 81 miles. This water course, in length
and force, is fully equal to Rvanna. This sup
ply had been turned into the canal few days be-
fore left Schenectady but it was filling slowly
as to excite the approximations of Mr.. Wright, the
principal engineer of the western canal, that it
would be found insufficient for the purpose of the
navigation; and accordingly, the fertile mind of
this Brindley of the west had already devised
pcdient to meet the exgency. His plan was to sup
ply the eventual deficiency by machinery like the
Philadelphia watcr-works, where it is proven, by
happy combination of science and the arts, that
low head of any constant and sufficiently abundant
stream, may be made to raise large volume of its
own body TO considerable elevation.
Thus, the experience of New-York, in that divi-
sion of the western canal between Little Falls and
Schohare, seems to fix the average length to which
feeder from the river will maintain the navigation
at about fifteen miles-allowing the Canagohar
supply to be half equal to feeder from the river
and estimating MIR. Wright's proposed additional
supply to the Schenectady division of 81 miles, at
one-third of the demand leaves eighteen miles to be
supplied by the Schshare creek and its reservoirs.
So that 1t seems to be dcducble from the experience
of New-York, that feeder of equal volume to the
canal may be relied upon to maintain the navigate
on from fifteen to eighteen miles,
How the "diminution in the volume of water in
canal is affected by the different kinds of clay or
soil through which it may have to pass" my obser-
vations on the NewYork canal do not enable me
to speak confidently. There being great uniformi-
ty in the composition of the earth along the valley
of the Mohawk, there were opportunities afford
ed of making the comparison as to variety of Soils
and to have drawn any general conclusions from
the wastings of the new and unsettled entertainments
would have been manifestly erroneous; especially,
experience the first divisions of the work had
shown that time and continued to render the ca
nal less and less subject to leakage. found uni
formly along the valley of the Mohawk, larger
proportion of sand than is to be found along the
valley of James river, within my knowledge of the
country, and hence conclude the character of the
earth along the valley of James river will be found
more favorable to a canal than that of the Mo-
hawk.
Secondly, ITO learn from their experience, what
effect is produced upon their banks by abrasion or
| abrupton in time of freshes"
The recent construction of that section of the
western canal along the ravine of the Mohawk the
only part subject TO nundation, had not afforded
much experience upon this point. There had been
parts OF the canal at different points, overfown with
but inconsiderable and temporary injury And I
understood it to be the opinion of Mr. Wright, that
did not regard occasional foundations a serious
cause of Alarm with the precautions which had been
taken to guard against their injurious effects And
that this was the settled opinion of the canal COM
missoners also, was sufficiently manifest, from the
ocation of the canal being at various points below
he level, TO which the foundations of the river have
| cen known frequently to rise. For instance, OBJ
erved at the mouth of Schohare creek, the top-wa-
Ter line OF the CANAL is within ten feet of the level
OF the river in its ordinary state; and at several
ther points, useless here to be designated the differ
ence OF level between the water of the canal and ri
yer, was between eleven and twelve feet only The
precautions taken in the formation of all embark.
ments, subject to be abraded by high water and IA.
pid currents, is to give the bank slope of not less
imam 40 degrees, and to protect the face of it. by
pavement of large stone, laid perpendicular to III,
lace OF the crnbankmenr, and varying in thickness
according to the size of stone from foot to eipb
teen inches For this, they pay SO cents per cubic
YARD. The utmost confidence seemed TO be placed
IN as an efectual defence against all abrasure from
the currents; nor did discover in any of the nu.
merous instances where the embankment of the ca
nal had encroached upon the channel of the river
and OF course was subject in all states of the river
10 the chahng OF the current upon part of its
face, that there was any injury from 1t. was in
formed by Mr. Wright, that these heavy slopine
paVements had been found TO resist more effectua y
| the ice freshets so formidable i'm the Mohawk than
the strongest perpendicular usual battered walls
OF which saw striking proof at the Little Falls
Al this dlfhcult pass, it became necessary to form
the canal within the channel of the river by wall
running parallel with the perpendicular rocky bar
rier which here forms the southern boundary of the
river, for the distance of half mile. This wall.
| T. Hpfty Low,
skill OF the best workmanship, had yielded to the
pressure Of the pudding and volume of water with
IN, and the assaults of the freshets upon its base
without, until II threatened to fall, but was SUM-
ported at various places, by large masses of loose
tone, thrown into the river at its base forming n
| oundaton wide enough to maintain a sloping mass
| Of the same materials to a level with the water of
| inc canal. This was in fact, resorting by more
expensive course, to the slopng bank and stone face
which subsequent experience had SO strongly recon-
| n1ended.
Thirdly, " Iron aquedlcts or culverts."
MT. wright thinks, that cast iron culverts NAV
be advantageously used in particular situations
provided they are not less than an inch in thick
ness. Where they have failed on the New YorL
canal, he attributes it to the want of strength he
ing only half inch thick, rather than to the severity
OF their climate. In all cases, however where
here is sufficient elevation for culverts of masonar
he prefers them observing have the arches turned
and grouted with water lime.
Fourthly. I" Manner of constructing locks. and
prices at which they are built; the most approved
manner of filling them; prices of other labour con-
Dected with the subject of canals"
Their locks are universally of hewn stone, and.
or the most part, limestone, that being preferred
N account of its superior durability occasionally.
the sand or free-stone has been used and in e,r,a
instances, marble; but, every where with the excen
ton OF few of the first built locks on the middle
'ectiou, they are executed in mastery STYLE of