[1] Not a distinct sect, but a continuous type of Christology.
Hippolytus, however (_Philosophumena_, viii. 8-11), speaks of a
definite party who called themselves Docetae.
[2] 1 _Ep._ iv. 2, ii. 22, v. 6, 20; 2 _Ep._ 7, cf. Jerome (_Dial.
adv. Lucifer_. S 23 "Apostolis adhuc in saeculo superstitibus, adhuc
apud Judaeam Christi sanguine recenti, phantasma Domini corpus
asserebatur").
[3] _Ad Trall._ 9 f., _Ad Smyrn._ 2, 4, _Ad Ephes._ 7. Cf. Polycarp,
_Ad Phil._ 7.
DOCHMIAC (from Gr. [Greek: dochme], a hand's breadth), a form of verse,
consisting of _dochmii_ or pentasyllabic feet (usually o _ _ o -).
DOCK, a word applied to (1) a plant (see below), (2) an artificial basin
for ships (see below), (3) the fleshy solid part of an animal's tail,
and (4) the railed-in enclosure in which a prisoner is placed in court
at his trial. Dock (1) in O.E. is _docce_, represented by Ger.
_Dockea-blatter_, O.Fr. _docque_, Gael. _dogha_; Skeat compares Gr.
[Greek: daukos], a kind of parsnip. Dock (2) appears in Dutch (_dok_)
and English in the 16th century; thence it was adopted into other
languages. It has been connected with Med. Lat. _doga_, cap, Gr. [Greek:
doche], receptacle, from [Greek: dechesthai], to receive. Dock (3),
especially used of a horse or dog, appears in English in the 14th
century; a parallel is found in Icel. _docke_, stumpy tail, and Ger.
_Docke_, bundle, skein, is also connected with it. This word has given
the verb "to dock," to cut short, curtail, especially used of the
shortening of an animal's tail by severing one or more of the vertebrae.
The English Kennel Club (Rules, 1905, revised 1907) disqualifies from
prize-winning dogs whose tails have been docked; several breeds are,
however, excepted, e.g. varieties of terriers and spaniels, poodles,
&c., and such foreign dogs as may from time to time be determined by the
club. The prisoners' dock (4) is apparently to be referred to Flem.
_dok_, pen or hutch. It was probably first used in thieves' slang;
according to the _New English Dictionary_ it was known after 1610 in
"bail-dock," a room at the corner of the Old Bailey left open at the
top, "in which during the trials are put some of the malefactors"
(_Scots. Mag._, 1753).
DOCK, in botany, the name applied to the plants constituting the section
_Lapathum_ of the genus _Rumex_, natural order Polygonaceae. They are
biennial or perennial herbs with a stout root-stock, and glabrous
linear-lanceolate or oblong-lanceolate leaves with a rounded, obtuse or
hollowed base and a more or less wavy or crisped margin. The flowers are
arranged in more or less crowded whorls, the whole forming a denser or
looser panicle; they are generally perfect, with six sepals, six stamens
and a three-sided ovary bearing three styles with much-divided stigmas.
The fruit is a triangular nut enveloped in the three enlarged leathery
inner sepals, one or all of which bear a tubercle. In the common or
broad-leaved dock, _Rumex obtusifolius_, the flower-stem is erect,
branching, and 18 in. to 3 ft. high, with large radical leaves,
heart-shaped at the base, and more or less blunt; the other leaves are
more pointed, and have shorter stalks. The whorls are many-flowered,
close to the stem and mostly leafless. The root is many-headed, black
externally and yellow within. The flowers appear from June to August. In
autumn the whole plant may become of a bright red colour. It is a
troublesome weed, common by roadsides and in fields, pastures and waste
places throughout Europe. The great water dock, _R. hydrolapathum_,
believed to be the _herba britannica_ of Pliny (_Nat. Hist._ xxv. 6), is
a tall-growing species; its root is used as an antiscorbutic. Other
British species are _R. crispus_; _R. conglomeratus_, the root of which
has been employed in dyeing; _R. sanguineus_ (bloody dock, or
bloodwort); _R. palustris_; _R. pulcher_ (fiddle dock), with
fiddle-shaped leaves; _R. maritimus_; _R. aquaticus_; _R. pratensis_.
The naturalized species, _R. alpinus_, or "monk's rhubarb," was early
cultivated in Great Britain, and was accounted an excellent remedy for
ague, but, like many other such drugs, is now discarded.
DOCK, in marine and river engineering. Vessels require to lie afloat
alongside quays provided with suitable appliances in sheltered sites in
order to discharge and take in cargoes conveniently and expeditiously;
and a basin constructed for this purpose, surrounded by quay walls, is
known as a dock. The term is specially applied to basins adjoining tidal
rivers, or close to the sea-coast, in which the water is maintained at a
fairly uniform level by gates, which are closed when the tide begins to
fall, as exemplified by the Liverpool and Havre docks (figs. 1 and 2).
Sometimes, however, at ports situated on tidal rivers near their tidal
limit, as at Glasgow (fig. 3), Hamburg and Rouen, and at some ports near
the sea-coast, such as Southampton (fig. 4) and New York, the tidal
range is sufficiently moderate for dock gates to be dispensed with, and
for open basins and river quays to serve for the accommodation of
vessels. For ports established on the sea-coast of tideless seas, such
as the Mediterranean, on account of the rivers being barred by deltas at
their outlets, like the Rhone and the Tiber, and thus rendered
inaccessible, open basins, provided with quays and protected by
breakwaters, furnish the necessary commercial requirements for sea-going
vessels, as for example at Marseilles (fig. 5), Genoa, Naples and
Trieste. These open basins, however, are precisely the same as closed
docks, except for the absence of dock gates, and the accommodation for
shipping at the quays round basins in river ports is so frequently
supplemented by river quays, that closed docks, open basins and river
quays are all naturally included in the general consideration of dock
works.
[Illustration: FIG. 1.--Liverpool Docks, North End]
[Illustration: FIG. 2.--Havre Docks and Outer Harbour.]
[Illustration: FIG. 3.--Glasgow Docks.]
[Illustration: FIG. 4.--Southampton Docks and River Quays.]
Sites for Docks.
Low-lying land adjoining a tidal river or estuary frequently provides
suitable sites for docks; for the position, being more or less inland,
is sheltered; the low level reduces the excavation required for forming
the docks, and enables the excavated materials to be utilized in raising
the ground at the sides for quays, and the river furnishes a sheltered
approach channel. Notable instances of these are the docks of the ports
of London, Liverpool, South Wales, Southampton, Hull, Belfast, St
Nazaire, Rotterdam, Antwerp and Hamburg. Sometimes docks are partially
formed on foreshores reclaimed from estuaries, as at Hull, Grimsby,
Cardiff, Liverpool, Leith and Havre; whilst at Bristol, a curved portion
of the river Avon was appropriated for a dock, and a straight cut made
for the river. By carrying docks across sharp bends of tidal rivers,
upper and lower entrances can be provided, thereby conveniently
separating the inland and sea-going traffic; and of this the London,
Surrey Commercial, West India, and Victoria and Albert docks are
examples on the Thames and Chatham dockyard on the Medway. Occasionally,
when a small tidal river has a shallow entrance, or an estuary exhibits
signs of silting up, docks alongside, formed on foreshores adjoining the
sea-coast, are provided with a sheltered entrance direct from the sea,
as exemplified by the Sunderland docks adjacent to the mouth of the
river Wear, and the Havre docks at the outlet of the Seine estuary (fig.
2). Some old ports, originally established on sandy coasts where a
creek, maintained by the influx and efflux of the tide from low-lying
spaces near the shore, afforded some shelter and an outlet to the sea
across the beach, have had their access improved by parallel jetties and
dredging; and docks have been readily formed in the low-lying land only
separated by sand dunes from the sea, as at Calais, Dunkirk (fig. 6) and
Ostend (see HARBOUR). In sheltered places on the sea-coast, docks have
sometimes been constructed on low-lying land bordering the shore, with
direct access to the sea, as at Barrow and Hartlepool; whilst at
Mediterranean ports open basins have been formed in the sea, by
establishing quays along the foreshore, from which wide, solid jetties,
lined with quay walls, are carried into the sea at intervals at right
angles to the shore, being sheltered by an outlying breakwater parallel
to the coast, and reached at each end through the openings left between
the projecting jetties and the breakwater, as at Marseilles (fig. 5) and
Trieste, and at the extensions at Genoa (see HARBOUR) and Naples. Where,
however, the basins are formed within the partial protection of a bay,
as in the old ports of Genoa and Naples, the requisite additional
shelter has been provided by converging breakwaters across the opening
of the bay; and an entrance to the port is left between the breakwaters.
The two deep arms of the sea at New York, known as the Hudson and East
rivers, are so protected by Staten Island and Long Island that it has
been only necessary to form open basins by projecting wide jetties or
quays into them from the west and east shores of Manhattan Island, and
from the New Jersey and Brooklyn shores, at intervals, to provide
adequate accommodation for Atlantic liners and the sea-going trade of
New York.
[Illustration: FIG. 5.--Port of Marseilles. Basins and Extensions.]
Approach channels.
The accessibility of a port depends upon the depth of its approach
channel, which also determines the depth of the docks or basins to which
it leads; for it is useless to give a depth to a dock much in excess of
the depth down to which there is a prospect of carrying the channel by
which it is reached. The great augmentation, however, in the power and
capacity for work of modern dredgers, and especially of suction dredgers
in sand (see DREDGE), together with the increasing draught of vessels,
has resulted in a considerable increase being made in the available
depth of rivers and channels leading to docks, and has necessitated the
making of due allowance for the possibility of a reasonable improvement
in determining the depth to be given to a new dock. On the other hand,
there is a limit to the deepening of an approach channel, depending upon
its length, the local conditions as regards silting, and the resources
and prospects of trade of the port, for every addition to the depth
generally involves a corresponding increase in the cost of maintenance.
[Illustration: FIG. 6.--Dunkirk Docks and Jetty Channel.]
At tidal ports the available depth for vessels should be reckoned from
high water of the lowest neap tides, as the standard which is certain to
be reached at high tide; and the period during which docks can be
entered at each tide depends upon the nature of the approach channel,
the extent of the tidal range and the manner in which the entrance to
the docks is effected. Thus where the tidal range is very large, as in
the Severn estuary, the approach channels to some of the South Wales
ports are nearly dry at low water of spring tides, and it would be
impossible to make these ports accessible near low tide; whereas at high
water, even of neap tides, vessels of large draught can enter their
docks. At Liverpool, with a rise of 31 ft. at equinoctial spring tides,
owing to the deep channel between Liverpool and Birkenhead and into the
outer estuary of the Mersey in Liverpool Bay, maintained by the
powerful tidal scour resulting from the filling and emptying of the
large inner estuary, access to the river by the largest vessels has been
rendered possible, at any state of the tide, by dredging a channel
through the Mersey bar; but the docks cannot be entered till the water
has risen above half-tide level, and the gates are closed directly after
high water. A large floating landing-stage, however, about half a mile
in length, in front of the centre of the docks, connected with the shore
by several hinged bridges and rising and falling with the tide, enables
Atlantic liners to come alongside and take on board or disembark their
passengers at any time.
[Illustration: FIG. 7.--Tilbury Docks.]
Comparatively small tidal rivers offer the best opportunity of a
considerable improvement in the approach channel to a port; for they can
be converted into artificially deep channels by dredging, and their
necessary maintenance is somewhat aided by the increased influx and
efflux of tidal water due to the lowering of the low-water line by the
outflow of the ebb tide being facilitated by the deepening. Thus
systematic, continuous dredging in the Tyne and the Clyde has raised the
Tyne ports and Glasgow into first-class ports. In large tidal rivers and
estuaries, docks should be placed alongside a concave bank which the
deep navigable channel hugs, as effected at Hull and Antwerp, or close
to a permanently deep channel in an estuary, such as chosen for Garston
and the entrance to the Manchester ship canal at Eastham in the inner
Mersey estuary, and for Grimsby and the authorized Illingham dock in the
Humber estuary; for a channel carried across an estuary to deep water
requires constant dredging to maintain its depth. Occasionally,
extensive draining works and dredging have to be executed to form an
adequately deep channel through a shifting estuary and shallow river to
a port, as for instance on the Weser to Bremerhaven and Bremen, on the
Seine to Honfleur and Rouen, on the Tees to Middlesborough and Stockton,
on the Ribble to Preston, on the Maas to Rotterdam and on the Nervion to
Bilbao (see RIVER ENGINEERING). Southampton possesses the very rare
combination of advantages of a well-sheltered and fairly deep estuary, a
rise of only 12 ft. at spring tides, and a position at the head of
Southampton Water at the confluence of two rivers (fig. 4), so that,
with a moderate amount of dredging and the construction of quays along
the lower ends of the river with a depth of 35 ft. in front of them at
low water, it is possible for vessels of the largest draught to come
alongside or leave the quays at any state of the tide. This circumstance
has enabled Southampton to attract some of the Atlantic steamers
formerly running to Liverpool.
Ports on tideless seas have to be placed where deep water approaches the
shore, and where there is an absence of littoral drift. The basins of
such ports are always accessible for vessels of the draught they provide
for; but they require most efficient protection, and, unlike tidal
ports, they are not able on exceptional occasions to admit a vessel of
larger draught than the basins have been formed to accommodate.
Occasionally, an old port whose approach channel has become inadequate
for modern vessels, or from which the sea has receded, has been provided
with deep access from the sea by a ship canal, as exemplified by
Amsterdam and Bruges; whilst Manchester has become a seaport by similar
works (see MANCHESTER SHIP CANAL). In such cases, however, perfectly
sheltered open basins are formed inland at the head of the ship canal,
in the most convenient available site; and the size of vessels that can
use the port depends wholly on the dimensions and facility of access of
the ship canal.
[Illustration: FIG. 8.--Barry Docks.]
Design of Docks.
Docks require to be so designed that they may provide the maximum
length of quays in proportion to the water area consistent with easy
access for vessels to the quays; but often the space available does
not admit of the adoption of the best forms, and the design has to be
made as suitable as practicable under the existing conditions. On this
account, and owing to the small size of vessels in former times, the
docks of old ports present a great variety in size and arrangement,
being for the most part narrow and small, forming a sort of string of
docks communicating with one another, and provided with locks or
entrances at suitable points for their common use, as noticeable in
the older London and Liverpool docks. Though narrow timber jetties
were introduced in some of the wider London docks for increasing the
length of quays by placing vessels alongside them, no definite
arrangement of docks was adopted in carrying out the large Victoria
and Albert docks between 1850 and 1880; whilst the Victoria dock was
made wide with solid quays, provided with warehouses, projecting from
the northern quay wall, thereby affording a large accommodation for
vessels lying end on to the north quay, the Albert dock subsequently
constructed was given about half the width of the earlier dock, but
made much longer, so that vessels lie alongside the north and south
quays in a long line. This change of form, however, was probably
dictated by the advantage of stretching across the remainder of the
wide bend, in order to obtain a second entrance in a lower reach of
the river. The Tilbury docks, the latest and lowest docks on the
Thames, were constructed on the most approved modern system,
consisting of a series of branch docks separated by wide,
well-equipped solid quays, and opening straight into a main dock or
basin communicating with the entrance lock, in which vessels can turn
on entering or leaving the docks (fig. 7). The most recently
constructed Liverpool docks, also, at the northern end have been given
this form; and the older docks adjoining them to the south have been
transformed by reconstruction into a similar series of branch docks
opening into a dock alongside the river wall, leading to a half-tide
basin or river entrances (fig. 1). The Manchester and Salford docks
were laid out on a precisely similar system, which was also adopted
for the most recent docks at Dunkirk (fig. 6) and Prince's dock at
Glasgow (fig. 3), and at some of the principal Rhine ports; whilst the
Alexandra dock at Hull resembles it in principle. The basins in
tideless seas have naturally been long formed in accordance with this
system (fig. 5). The Barry docks furnish an example of the special
arrangements for a coal-shipping port, with numerous coal-tips served
by sidings (fig. 8).
Tidal and half-tide basins.
Tidal basins, as they are termed, are generally interposed in the
docks of London between the entrance locks and the docks, with the
object of facilitating the passage of vessels out of and into the
docks before and after high water, by lowering the water in the basin
as soon as the tide has risen sufficiently, and opening the lock gates
directly a level has been formed with the tide in the river. Then the
vessels which have collected in the basin, when level with the dock,
are readily passed successively into the river. The incoming vessels
are next brought into the basin, and the gates are closed; and the
water in the basin having been raised to the level in the dock, the
gates shutting off the basin from the dock when the water was lowered
are opened, and the vessels are admitted to the dock. In this manner,
by means of an inner pair of gates, the basin can be used as a large
lock without unduly altering the water-level in the dock, and saves
the delay of locking most of the vessels out and in, the lock being
only used for the smaller vessels leaving early or coming in late on
the tide. Similar tidal basins have also been provided at Cardiff,
Penarth, Barry (fig. 8), Sunderland, Antwerp and other docks.
The large half-tide docks introduced at the most modern Liverpool
docks (fig. 1) serve a similar purpose as tidal basins; but being much
larger, and approached by entrances instead of locks, the exit and
entrance of vessels are effected by lowering their water-level on a
rising tide, and opening the gates, which are then closed at high
water to prevent the lowering of the water-level in the dock, and to
avoid closing the gates against a strong issuing current.
The tidal basins outside the locks at Tilbury and Barry are quite open
to the tide, and have been carried down to 24 ft. and 16 ft.
respectively below low water of spring tides, in order to afford
vessels a deep sheltered approach to the lock in each case, available
at or near low water (figs. 7 and 8). Such basins, however, open to a
considerable tidal range where the water is densely charged with silt,
are exposed to a large deposit in the fairly still water, and their
depth has to be constantly maintained by sluicing or dredging.
River quays.
Where the range of tide is moderate, or on large inland rivers, docks
or basins are usefully supplemented by river quays, which though
subject to changes in the water-level, and exposed to currents in the
river, are very convenient for access, and are sometimes very
advantageously employed in regulating a river and keeping up its banks
when deepened by dredging. Generally 10 to 12 ft. is the limit of the
tidal range convenient for the adoption of open basins and river
quays; but the banks of the Tyne have been utilized for quays, jetties
and coal-staiths, with a somewhat larger maximum tidal range; and a
long line of quays stretching along the right bank of the Scheldt in
front of Antwerp, constructed so as to regulate this reach of the
river, accommodates a large sea-going traffic, with a rise at spring
tides of 15 ft.
Excavations for docks.
When a dock has to be formed on land, the excavation is effected by
men with barrows and powerful steam navvies, loading into wagons drawn
in trains by locomotives to the place of deposit, usually to raise the
land at the sides for forming quays. Directly the underground
water-level is reached, the water has to be removed from the
excavations by pumps raising the inflowing water from sumps, lined
with timber, sunk down below the lowest foundations at suitable
positions, so that the lower portions of the dock walls and sills of
the lock or entrance may be built out of water. A cofferdam has to be
constructed extending out from the bank of the river or approach
channel in front of the site of the proposed entrance or lock, so that
the excavations for the entrance to the dock may be pushed forwards,
and the lock or entrance built under its protection. Sometimes the
lowest portion of the excavation for the dock can be accomplished
economically by dredging, after the dock walls and lock have been
completed and the water admitted.
Where a dock is partially or wholly constructed on reclaimed land, the
reclamation bank for enclosing the site and excluding the tide has to
be undertaken first by tipping an embankment from each end with
wagons, protected and consolidated along its outer toe by rubble stone
or chalk. When the ends of the embankments are approaching one
another, it is essential to connect them by a long low bank of
selected materials brought up gradually in successive layers, and
retaining the water in the enclosure to the level of this bank, so
that the influx and efflux of the tide, filling and emptying the
reclaimed area, may take place over a long length, and in smaller
volume as the low bank is raised. In this way a reduction is effected
of the tidal current in and out, which in the case of a large
enclosure and a considerable tidal range, would create such a scour in
the narrowing gap between two high embankments as to wash away their
ends and prevent the closing of the gap. Occasionally the final
closure is effected by lowering timber panels in grooves between a
series of piles driven down at intervals across the gap. On the
closing of the reclamation bank the water is pumped out; and the
excavation is carried on in the ordinary manner. It is very important
that such an embankment should be carried well above the level of the
highest tide which might be raised by a high wind; and in exposed
sites, the outer slope of the bank should be protected by pitching
from the action of waves, for any overtopping or erosion of the bank
might result in a large breach through it, and the flooding of the
works inside.
Foundations for dock walls.
Docks are generally surrounded by walls retaining the quays, alongside
which vessels lie for discharging and taking in cargoes. In order to
ascertain the nature of the strata upon which these walls have to be
founded, borings are taken at the outset to the requisite depth at
intervals near the line of the walls, but inside the dock area if the
piercing of quicksand is anticipated, as in excavating for the
foundations, these holes might give rise to the outflow, under
pressure, of underlying quicksand into the foundations. As docks are
generally formed near rivers or estuaries, these strata are commonly
alluvial; but being situated at some depth below the surface, they are
usually fairly hard. When they consist of gravel, clay or firm sand,
the walls can be founded on the natural bottom excavated a few feet
below the bottom of the dock, their weight being somewhat distributed
by making them rest on a broad bed of concrete filling up the
excavation at the bottom. When, however, fine sand or silt charged
with water, or quicksand is met with at the required depth, the
necessary pumping and excavation for the foundations might occasion
the influx of sand or silt with the water into the excavations,
leading to settlement and slips; or the soft stratum might be too
thick to remove. The wall may then be founded on bearing piles driven
down to a solid stratum, and having their tops joined together by
walings and planking, or by a layer of concrete, upon which the wall
is built. Or the soft stratum can be enclosed with a double row of
sheet piling along the front and back of the line of wall, by which it
sometimes becomes sufficiently confined and consolidated to sustain
the weight of the wall on a broad foundation of concrete; or it can be
excavated without any danger of sand or silt running in from outside;
whilst the sheet piling at the back relieves the wall to some extent
from the pressure of the earth behind it, and in front retains the
wall from sliding forwards. Firmer foundations have been obtained by
sinking brick, concrete or masonry wells through soft ground to a
solid stratum, upon which the dock wall is built. Clusters of small
concrete cylinders, in sets of three in front, and a line of double
cylinders at the back, were used for the foundations of the walls of
Prince's dock at Glasgow. Wells of rubble masonry were sunk in the
silty foreshore of the Seine estuary for the walls of the Bellot docks
at Havre; and they served as piers, connected by arches, for the
foundations of a continuous dock wall above, being carried down to a
considerable depth through alluvium at the St Nazaire, Bordeaux and
Rochefort docks. These well foundations, derived from the old Indian
system, are built up upon a curb, sometimes furnished with a cutting
edge underneath, and gradually sunk by excavating inside; and
eventually the central hollow is filled up solid with concrete or
masonry.
Dock walls.
The walls round a dock serve as retaining walls to keep up the quays;
and though they have the support of the water in front of them when
the docks are in use, they have to sustain the full pressure of the
filling at the back on the completion of the dock before the water is
admitted. They have, accordingly, to be increased in thickness
downwards to support the pressure increasing with the depth. This
pressure, with perfectly dry material, would be represented by the
weight of half the prism of filling between the natural slope of the
material behind and the back of the wall; but the pressure is often
increased by the accumulation of water at the back, which, with fine
silty backing, is liable to exert a sort of fluid pressure against the
wall proportionate to the density of the mixture of silt and water.
The increase of thickness towards the base used formerly to be
effected by a batter on the face, as well as by steps out at the back;
but the vertical form now given to the sides of large vessels
necessitates a corresponding fairly vertical face for the wall, to
prevent the upper part of the vessel being kept unduly away from the
quay. Examples of the most modern types of dock walls are given in
figs. 9 to 12.
[Illustration: FIG. 9.--Havre Bellot Dock Wall.]
The height of a dock wall depends upon the depth of water always
available for vessels, at tideless sea-ports and at ports removed from
tidal influences, such as Manchester, Bruges and the ports on the
Rhine; this depth should not be less than 28 to 30 ft. for large
sea-going vessels, together with a margin of 5 to 8 ft. above the
normal water-level for the quays, and the foundations below. At tidal
ports, however, an addition has to be made equal to the difference in
height between the high-water levels of spring and neap tides; so that
at ports with a large tidal range, such as the South Wales ports on
the Severn estuary and Liverpool, specially high dock walls are
necessary. Under normal conditions, a dock wall should be given a
width at a height half-way between dock-bottom and quay-level, equal
to one-third of its height above dock-bottom, and a width of half this
height at dock-bottom.
[Illustration: FIG. 10.--Liverpool Dock Wall.]
Dock walls are constructed of masonry, brickwork or concrete, or of
concrete with a facing of masonry or brickwork. Masonry is adopted
where large stone quarries are readily accessible, in the form of
rubble masonry with dressed stone on the face, as for instance at the
Hull and Barry docks, and forms a very durable wall; but strong
overhead staging carrying powerful gantries is necessary for laying
large blocks. Brickwork has been often used where bricks are the
ordinary building material of the district or can be made on the
works, and requires only ordinary scaffolding; and harder or pressed
bricks are employed for the facework. Concrete is very commonly
resorted to now where sand and stones are readily procured; and where
clean, sharp sand and gravel are found in thick layers in the
excavations for a dock, as in the alluvial strata bordering the
Thames, dock walls can be constructed cheaply and economically with
concrete deposited within timber framing, dispensing with regular
scaffolding and skilled labour. Such walls require to be given a
facing of stronger concrete, or of blue bricks, as at Tilbury, to
guard against abrasion by vessels, chains and ropes; and dock walls
are commonly provided at the top with granite or other hard stone
coping where the wear is greatest. The foundations for dock walls are
excavated in a trench below dock-bottom, only lined with timbering
where the faces of the trench cannot stand for a short time without
support, and with sheet piling through very unstable silt or sand; and
the trench is conveniently filled up solid with concrete, carried out
in short lengths in untrustworthy ground. To reduce the amount of
filling behind the wall, the excavation at the back above dock-bottom,
preparatory for the trench, is given as steep a slope as practicable,
supported sometimes towards the base by timbering and struts; but
occasionally the wall is built within a timbered trench carried down
to the required depth, before the excavation for the dock in front of
it has been executed, as effected at Tilbury. The filling at the back
is thus reduced to a minimum, and the lower portion of the excavation
can be accomplished by dredging, if expedient, after the admission of
the water, the dock wall in this way being exposed to the least
possible pressure behind.
[Illustration: FIG. 11.--Tilbury Basin Wall.]
The walls of open basins are often constructed out of water precisely
like dock walls, as in the case of the basins forming the Manchester,
Bruges and Glasgow docks; and basin walls open to the tide, as at
Glasgow and in the tidal basin outside Tilbury docks (fig. 7), differ
only from dock walls in being exposed to variations in the pressure at
the back resulting from the lowering of the water-level in front,
which is, indeed, shared to some extent by the walls round closed
docks where the difference in the high-water levels of springs and
neaps is considerable. The walls, however, round basins in tideless
seas, such as Marseilles, occasionally those inside harbours, and
especially quay walls along rivers and round open basins alongside
rivers, have to be constructed under water.
[Illustration: FIG. 12.--Barry Dock Wall.]
[Illustration: FIG. 13.--Marseilles Quay Wall.]
[Illustration: FIG. 14.--Antwerp Quay Wall, founded by compressed
air.]
[Illustration: FIG. 15.--Caracciolo Jetty Quay Wall, Genoa.]
Open basin and river quay walls founded under water.
At Marseilles, the simple expedient was long ago adopted of
constructing the quay walls lining the basins formed in the sea, by
depositing tiers of large concrete blocks on a rubble foundation, one
on top of the other, till they reached sea-level, and then building a
solid masonry quay wall out of water on the top up to quay-level,
faced with ashlar (fig. 13), the wall being backed by rubble for some
distance behind up to the water-level. The same system was employed
for the quay walls at Trieste, and at Genoa and other Italian ports. A
quay wall inside Marmagao harbour, on the west coast of India, was
erected on a foundation layer of rubble by the sloping-block system,
to provide against unequal settlement on the soft bottom (see
BREAKWATER). The quay walls alongside the river Liffey, and round the
adjacent basins below Dublin, were erected under water by building
rubble-concrete blocks of 360 tons on staging carried out into the
water, from which they were lifted one by one by a powerful floating
derrick, which conveyed the block to the site, and deposited it on a
levelled bottom at low tide in a depth of 28 ft., raising the wall a
little above low water. After a row of these blocks had been laid, and
connected together by filling the grooves formed at the sides and the
interstices between the blocks with concrete, a continuous masonry
wall faced with ashlar was built on the top out of water. A quay wall
was built up to a little above low water on a similar principle at
Cork, with three smaller blocks as a foundation, in lengths of 8 ft.
Cylindrical well foundations have been extensively used for the
foundations of the quay walls along the Clyde, formerly made of brick,
but subsequently of concrete, sunk through a considerable variety of
alluvial strata, but mostly sand and gravel fully charged with water.
Compressed air in bottomless caissons has been increasingly employed
in recent years for carrying down the subaqueous foundations of river
quay walls, through alluvial deposits, to a solid stratum. About 1880,
a long line of river quays was commenced in front of Antwerp,
extending in the central portion a considerable distance out into the
Scheldt, with the object of regulating the width of the river
simultaneously with the provision of deep quays for sea-going vessels;
and the quay wall was erected, out of water, on the flat tops of a
series of wrought-iron caissons, 82 ft. long and 29-1/2 ft. wide,
constructed on shore, floated out one by one to their site in the
river between two barges, and gradually lowered as the wall was built
up inside a plate-iron enclosure round the roof of the caisson, which
was eventually sunk by aid of compressed air through the bed of the
river to a compact stratum (fig. 14). The weight of the wall
counteracted the tendency of the caisson and the enclosure above it to
float; and the caisson, furnished with seven circular wrought-iron
shafts, provided with air-locks at the top for the admission of men
and materials and for the removal of the excavations, was gradually
carried down by excavating inside the working chamber at the bottom,
6-1/4 ft. high, till a good foundation was reached. The working chamber
was then filled with concrete through some of the shafts, the
plate-iron sides of the upper enclosure were removed to be used for
another length of wall, the shafts were drawn out and the hollows left
by them filled with concrete, the apertures between adjacent lengths
were closed at each face with wooden panels and filled with concrete,
and a continuous quay wall was completed above. The most recent quay
walls constructed in the old harbour at Genoa were founded under
water on a rubble mound in a similar manner by the aid of compressed
air (fig. 15). Quay walls also on the Clyde have been founded on
caissons, consisting of a bottomless steel structure, surmounted by a
brick superstructure having hollows filled with concrete, in lengths
of 80 ft. and 27 ft., and widths of 18 ft. and 21 ft. respectively,
carried down by means of compressed air from 54 to 70 ft. below
quay-level, on the top of which a continuous wall of concrete, faced
with brickwork, and having a granite coping, was built up from near
low-water level (fig. 16). In many cases where soft strata extend to
considerable depths, river quays and basin walls have been constructed
by building a light quay wall upon a series of bearing and raking
piles driven into, and if possible through, the soft alluvium. Thus
the walls along the Seine, and round the basins at Rouen, were built
upon bearing piles carried down through the alluvial bed of the river
to the chalk. The lower portion of the quay wall was constructed of
concrete faced with brickwork within water-tight timber caissons,
resting upon the piles at a depth of 9-3/4 ft. below low water; and upon
this a rubble wall faced with bricks was erected from low water to
quay-level, backed by rubble stone laid on a timber flooring supported
by piles, together with chalk, to form a quay right back to the top of
the slope of the bank of the deepened river (fig. 17). The quay walls
of the open basins bordering the Hudson river at New York have had, in
certain parts, to be founded on bearing piles combined with raking
piles, driven into a thick bed of soft silt where no firm stratum
could be reached, and where, therefore, the weight could only be borne
by the adherence of the long piles in the silt. Before driving the
piles, however, the silt round the upper part of the piles and under
the quay wall was consolidated by depositing small stones in a trench
dredged to a depth of 30 ft. below low water; the piles were driven
through these stones, and were further kept in place by a long toe of
rubble stone in front and a backing of rubble stone behind carried
nearly up to quay-level, behind which a light filling of ashes and
earth was raised to quay-level. The slight quay wall resting upon the
front rows of bearing piles was carried up under water by 70-ton
concrete blocks deposited by means of a floating derrick; and the
upper part of the wall was built of concrete faced with ashlar masonry
(fig. 18). The basin and quay walls at Bremen, Bremerhaven and Hamburg
were built on a series of bearing and raking piles driven down to a
firm stratum, the wall being begun a few feet below low water. At
Southampton, ferro-concrete piles were employed in constructing the
deep quays; and a wharfing of timber pilework has been frequently used
for river quays.
[Illustration: FIG. 16.--Glasgow River Quay Wall.]
[Illustration: FIG. 17.--Rouen Quay Wall.]
Where the increase of trade is moderate and the conditions of the
traffic permit, and also at coal-shipping ports, economy in
construction is obtained by giving sloping sides to a portion of a
dock in place of dock walls, the slope being pitched where necessary
with stone; and the length of the slope projecting into a dock is
sometimes reduced by substituting sheet piling for the slope at the
toe up to a certain height. By this arrangement jetties can be carried
out across the slope as required, enabling vessels to lie against
their ends; and coal-tips are very conveniently extended out across
the slope at suitable intervals (fig. 8).
Failures of dock walls.
As dock walls, especially before the admission of water into the dock,
constitute high retaining walls, not infrequently founded upon soft or
slippery strata, and backed up with the excavated materials from
alluvial beds, into which water is liable to percolate, they are
naturally exposed under unfavourable conditions to the danger of
failure. A dock wall erected on unsatisfactory foundations is liable,
where the bottom is soft, to settle down at its toe, owing to the
pressure at the back, and to fall forwards into the dock, as occurred
at Belfast; or where the silty bottom slips forward under the weight
of the backing, the wall may follow the slip at the bottom and settle
down at the back, falling to some extent backwards, as exemplified by
the failure of the Empress basin wall at Southampton. The most common
form, however, of failure is the sliding forwards of a dock wall, with
little or no subsidence, on a silty or slippery stratum under the
pressure imposed by the backing. Thus the Kidderpur dock walls furnish
an instance of sliding forwards on muddy silt, and part of the South
West India dock walls on two underlying, detached, slippery seams of
London clay.
To avoid these failures with untrustworthy foundations, great care has
to be exercised in selecting the best hard material available,
unaffected by water, for the backing, which should be brought up in
thin, horizontal layers carefully consolidated; and where there is a
possibility of water accumulating at the back, pipes should be
introduced at intervals near the bottom right through the wall in
building it, and rubble stone deposited close to the back of the wall,
so as to carry off any water from behind, these pipes being stopped up
just before the water is let into the dock. These precautions,
moreover, are assisted by reducing the amount of backing to a minimum
in the construction of the wall, best effected by building the wall
inside a timbered trench. The liability to slide forwards can be
obviated by carrying down the foundations of the wall sufficiently
below dock-bottom to provide an efficient buttress of earth in front
of the wall, and also by making the base of the wall slope down
towards the back, thereby forcing the wall in sliding forwards to
mount the slope, or to push forward a larger mass of earth; whilst a
row of sheet piling in front of the foundations offers a very
effectual impediment to a forward movement, and, in combination with
bearing piles, prevents settlement at the toe in soft ground. In very
treacherous foundations it may be advisable to defer the completion of
the backing till after the admission of the water; but the additional
stability given to a retaining wall or reservoir dam by an ample
batter in front, is precluded in dock walls by the modern requirements
of vessels.
[Illustration: FIG. 18.--New York Quay Wall, Hudson river.]
Maintenance of depth.
Silt accumulates in docks where the lowering of the water-level by
locking, the drawing down of half-tide basins, and the raising of the
water at spring tides, involve the admission of considerable volumes
of tidal water heavily charged with silt, which is deposited in still
water and has to be periodically removed by dredging. To avoid this,
the water is sometimes replenished from some clear inland source, an
arrangement adopted at some of the South Wales ports opening into the
muddy Severn estuary, and at the Alexandra dock, Hull, to exclude the
silty waters of the Humber. At the Kidderpur docks on the Hugli, the
water from the river for replenishing the docks is conducted by a
circuitous canal, in which it deposits its burden of silt before it is
pumped into the docks.
Equipment on quays.
In order to deal expeditiously with the cargoes and goods brought into
and despatched from docks, numerous sidings communicating with the
railways of the district are arranged along the quays, which are also
provided with steam, hydraulic or electric travelling cranes at
intervals alongside the docks, basins or river, for discharging or
loading vessels, and with sheds and warehouses for the storage of
merchandise, &c., the arrangements depending largely upon the special
trade of the port. Though different sources of power are sometimes made
use of at different parts of the same port, as for example at Hamburg,
where the numerous cranes are worked by steam, hydraulic power or most
recently by electricity, and a few by gas engines, it is generally most
convenient to work the various installations by one form of power from a
central station. Water-pressure has been very commonly used as the
motive power at docks, being generated by a steam-engine and stored up
by one or more accumulators, from which the water is transmitted under
pressure through strong cast-iron pipes to the hydraulic engines which
actuate the cranes, lifts, coal-tips, capstans, swing-bridges and gate
machinery throughout the docks (see POWER TRANSMISSION: _Hydraulic_).
The intermittent working of the machinery in docks results in a
considerable variation in the power needed at different times; but
economical working is secured by arranging that when the accumulators
are full, steam is automatically shut off from the pumping engines, but
is supplied again as soon as water is drawn off. Electricity affords
another means for the economical transmission of power to a distance
suited for intermittent working; as far back as 1902 it was being
adopted at Hamburg as the source of power for the machinery of the
extensive additional basins then recently opened for traffic.
Coal-tips.
At ports where the principal trade is the export of coal from
neighbouring collieries, special provision has to be made for its rapid
shipment. Coal-tips, accordingly, are erected at the sides of the dock
in these ports, with sidings on the quays at the back for receiving the
trains of coal trucks, from which two lines of way diverge to each
coal-tip, one serving for the conveyance of the full wagons one by one
to the tip, after passing over a weigh-bridge, and the other for the
return of the empty wagons to the siding where the empty train is made
up for returning to the colliery (fig. 8). Each full wagon is either run
at a low level upon a cradle at the tip, then raised on the cradle
within a wrought-iron lattice tower to a suitable height, and lastly,
tipped up at the back for discharging the coal; or it is brought along a
high-level road on to a cradle raised to this level on the tower, and
tipped up at this or some slightly modified level. The coal is
discharged down an adjustable iron shoot, gradually narrowed so as to
check the fall; and on first discharging into the hold of a vessel, an
anti-breakage box is suspended below the mouth of the shoot. When full,
this is lowered to the bottom of the hold and emptied, thereby gradually
forming a cone of coal upon which the coal can be discharged directly
from the shoot without danger of breakage. Other contrivances are also
adopted with the same object.
Dock extensions.
In designing dock works, it is expedient to make provision, as far as
possible, for future extensions as the trade of the port increases.
Generally this can be effected alongside tidal rivers and estuaries by
utilizing sites lower down the river, as carried out on the Thames for
the port of London, or reclaiming unoccupied foreshores of an estuary,
as adopted for extensions of the ports of Liverpool, Hull and Havre.
At ports on the sea-coast of tideless seas, it is only necessary to
extend the outlying breakwater parallel to the shore line, and form
additional basins under its shelter, as at Marseilles (fig. 5) and
Genoa (see HARBOUR). Quays also along rivers furnish very valuable
opportunities of readily extending the accommodation of ports. Ports,
however, established inland like Manchester, though extremely
serviceable in converting an inland city into a seaport, are at the
disadvantage of having to acquire very valuable land for any
extensions that may be required; but, nevertheless, some compensation
is afforded by the complete shelter in which the extensions can be
carried out, when compared with Liverpool, where the additions to the
docks can only be effected by troublesome reclamation works along the
foreshore to the north, in increasingly exposed situations.
_Dock Entrances and Locks._--The size of vessels which a port can admit
depends upon the depth and width of the entrance to the docks; for,
though the access of vessels is also governed by the depth of the
approach channel, this channel is often capable of being further
deepened to some extent by dredging; whereas the entrance, formed of
solid masonry or concrete, cannot be adapted, except by troublesome and
costly works sometimes amounting to reconstruction, to the increasing
dimensions of vessels. Accordingly, in designing new dock works with
entrances and locks, it is essential to look forward to the possible
future requirements of vessels. The necessity for such forethought is
illustrated by the rapid increase which has taken place in the size of
the largest ocean liners. Thus the "City of Rome," launched in 1881, is
560 ft. long, and 52-1/4 ft. beam, and has a maximum recorded draught of
27-1/2 ft.; the "Campania" and "Lucania," in 1893, measure 600 ft. by 65
ft.; the "Oceanic," in 1899, 685-1/2 ft. by 68-1/4 ft., with a maximum
draught of 31-1/3 ft.; the "Baltic," in 1903, 709 ft. by 75 ft., with a
maximum draught of 31-3/4 ft.; and the "Lusitania" and "Mauretania,"
launched in 1906, 787-1/2 ft. by 88 ft.
Dimensions of entrances and locks.
The width and depth of access to docks are of more importance than the
length of locks; for docks which are reached through entrances with a
single pair of gates have to admit vessels towards high water when the
water-level in the dock is the same as in the approach channel, or
through a half-tide basin drawn down to the level of the water outside,
and are therefore accessible to vessels of any length, provided the
width of the entrance and depth over the sill are adequate; whilst at
docks which are entered through locks, vessels which are longer than the
available length of the lock can get in at high water when both pairs of
gates of the lock are open. Open basins are generally given an ample
width of entrance, and river quays also are always accessible to the
longest and broadest vessels; but in a tidal river the available depth
has to be reckoned from the lowest low water of spring tides, instead of
from the lowest high water of neap tides, if the vessels in the open
basins and alongside the river quays have to be always afloat.
Many years ago the Canada lock at Liverpool, the outer North lock at
Birkenhead, the Ramsden lock and entrance at Barrow-in-Furness, and the
Eure entrance at Havre, were given a width of 100 ft. Probably this was
done with the view of admitting paddle steamers, since subsequent
entrances at Liverpool were given widths of 80 and 65 ft.; whereas none
of the locks in the port of London has been made wider than 80 ft.,
which has been the standard maximum width since the completion of the
Victoria dock in 1866. The widest locks at Cardiff are 80 ft., and the
entrance to the Barry docks is the same; but the lock of the Alexandra
dock, Hull, opened in 1885, was made 85 ft. wide. At Liverpool, where
the access to the docks is mainly through entrances, on account of the
small width between the river and the high ground rising at the back,
and where ample provision has to be made for the largest Atlantic
liners, though the entrances to the Langton dock, completed in 1881,
leading to the latest docks at the northern end were made 65 ft. wide,
with their sills 3 ft. below low water of spring tides and 20-1/2 ft.
below high water of the lowest neap tides, the two new entrances to the
deepened Brunswick dock near the southern end, giving access to the
adjacent reconstructed docks, completed in 1906, were made 80 and 100
ft. wide, with sills 28 ft. below high water of the lowest neap tides.
Moreover, the three new entrances to the new Sandon half-tide dock,
completed in 1906, communicating with the reconstructed line of docks to
the south of the Canada basin, and with the latest northern extensions
of the Liverpool docks, were made 40 ft. wide with a depth over the sill
of 24-1/2 ft., and 80 and 100 ft. wide on each end of the central
entrance, with sills 29 ft. below high water of the lowest neap tides,
each entrance being provided with two pairs of gates, in case of any
accident occurring to one pair, according to the regular custom at
Liverpool. Powers were also obtained in 1906 for the construction of a
half-tide dock and two branch docks to the north of the Hornby dock,
which are to be reached from the river by two entrances designed to be
130 ft. wide, with sills 38-1/2 ft. below high water of the lowest neap
tides, so as to meet fully the assumed future increase in the beam and
draught of the largest vessels; whilst the authorized extension of the
river wall northwards will enable additional docks to be constructed in
communication with these entrances when required.
Though, with the exception of Southampton and Dover, other British ports
do not aim, like Liverpool, at accommodating the largest Atlantic liners
at all times, the depths of the sills at the principal ports have been
increased in the most recent extensions. Thus at the port of London the
sills of the first lock of the Albert dock were 26-1/2 ft. below high water
of neap tides, and of the second lock adjoining, 32-1/2 ft. deep; whilst
the sills of the lock of the Tilbury docks are 40-1/2 ft. below high water
of neap tides. Moreover, in spite of the great range of tide at the
South Wales ports on the Severn estuary, the available depth at high
water of neap tides of 25 ft. at the Roath lock, Cardiff, was increased
in the lock of the new dock to 31-1/2 ft.; the depth at the entrance to
the Barry docks, opened in 1889, was 29-1/2 ft., but at the lock opened in
1896 was made 41-1/3 ft.; whilst a depth of 34 ft. has been proposed for
the new lock of the Alexandra dock extension at Newport, nearly 10 ft.
deeper than the existing lock sills there. Similar improvements in depth
have also been made or designed at other ports to provide for the
increasing draught of vessels.
The length of locks has also been increased, from 550 ft. at the Albert
dock, to 700 ft. at Tilbury in the port of London, from 300 ft. to 550
ft. at Hull, and from 350 ft. to 660 ft. at Cardiff. The lock at the
Barry docks is 647 ft. long, though only 65 ft. wide. A lock constructed
in connexion with the improvement works at Havre, carried out in
1896-1907, was given an available length of 805 ft. and a width of
98-1/2 ft., with a depth over the sills of 34-3/4 ft. at high water of
neap tides.
[Illustration: FIG. 19.--Barry Docks, Entrance.]
Entrances to docks.
Entrances with a single pair of gates, closing against a raised sill
at the bottom and meeting in the centre, have to be made long enough
to provide a recess in each side wall at the back to receive the gates
when they are opened, and to form a buttress in front on each side to
bear the thrust of the gates when closed against a head of water
inside. A masonry floor is laid on the bottom in continuation of the
sill, serving as an apron against erosion by water leaking between or
under the gates, and by the current through the sluiceways in the
gates, when opened for scouring the entrance channel or to assist in
lowering the water in a half-tide dock for opening the gates (fig.
19). A sluiceway in each side wall, closed by a vertical sluice-gate,
generally provided in duplicate in case of accidents and worked by a
machine actuated by hydraulic pressure, enables the half-tide basin to
be brought down to the level of the approach channel outside with a
rising tide, so that vessels may be brought into or passed out of the
basin towards high water. The advantages of these entrances are, that
they occupy comparatively little room where the space is limited, and
are much less costly than locks; whilst in conjunction with a
half-tide basin they serve the same purpose as a lock with a rising
tide. Vessels also pass more readily through the short entrances than
through locks; and as entrances are only used towards high water,
their sills need not be placed so low as the outer sills of locks to
accommodate vessels of large draught. On the other hand, they are
accessible for a more limited period at each tide than locks; and they
do not allow of the exclusion of silt-bearing tidal water, and
therefore necessitate a greater amount of dredging in the docks, and
especially in half-tide basins, for maintenance. Entrances, however,
at large ports are frequently supplemented by the addition of a lock
at some convenient site, rendering the ports accessible for the
smaller class of vessels for some time before and after high water, as
for instance at Liverpool, Barry, Havre and St Nazaire. A small basin
with an entrance at each end--an arrangement often adopted--is in
reality, for all practical purposes, a lock with a very large
lock-chamber. An entrance or passage with gates has also to be
provided at the inner end of a large half-tide basin like the basins
adopted at Liverpool, to shut off the half-tide basin from the docks
to which it gives access, and maintain their water-level when the
water is drawn down in the basin to admit vessels before high tide.
Reverse gates pointing outwards are sometimes added in passages to
docks and at entrances, to render the water-level in one set of docks
independent of adjacent docks, to exclude silty tidal water and very
high tides, and also to protect the gates of outer entrances in
exposed situations from swell, which might force them open slightly
and lead to a damaging shock on their closing again.
Locks at docks.
Locks differ from entrances in having a pair of gates with
arrangements similar to an entrance at each end, separated from one
another by a lock-chamber, which should be large enough to receive the
longest and broadest vessel coming regularly to the port. These dock
locks are similar in principle to locks on canals and canalized
rivers, but are on a much larger scale. The lock-chamber has its water
raised or lowered in proportion to the difference in level between the
water-level in the dock and the water in the entrance channel, by
passing water, when the gates are closed at both ends, from the dock
into the lock-chamber or from the lock-chamber into the entrance
channel, through large sluiceways in the side walls, controlled, as at
entrances, by vertical sluice-gates. In this way the vessel is raised
or lowered in the chamber, till, when a level has been reached, the
intervening pair of gates is opened and the vessel is passed into the
dock or out to the channel. Generally the upper and lower sills of a
lock are at the same level, a foot or two higher than dock-bottom; and
the depth at which they are laid is governed by the same
considerations as the sill of an entrance. Vessels longer than the
available length between the two pairs of gates can be admitted close
to high water, when the water in the dock and outside is at the same
level, and both pairs of gates can be opened. When the range of tide
at a port is large, and the depth in the approach channel is
sufficient to allow vessels to come up or go out some time before and
after high water, and also where the water in the dock is kept up to a
high level from an inland source to exclude very silty tidal water, it
is expedient to reduce the cost of construction by limiting the depth
of the excavations for the dock, and consequently also the height of
the dock walls, to what is necessary to provide a sufficient depth of
water below high water of the lowest neap tides, or below the
water-level to which the water in the dock is always maintained, for
the vessels of largest draught frequenting the port, or those which
may be reasonably expected in the near future. The upper sill of the
lock is then determined by the level of dock-bottom; but the lower
sill is taken down approximately to the depth of the bottom of the
approach channel, or to the depth to which it can be carried by
dredging, so as to enable the lock to admit or let out at any time all
vessels which can navigate the approach channel. Thus, for instance,
the outer and intermediate sills of the lock at the Barry docks are 9
ft. lower then the upper sill.
The foundations for the sill and side walls at each end of a lock, and
also for the side walls and invert commonly enclosing the lock-chamber
at the sides and bottom, are generally constructed simultaneously with
the dock works, under shelter of a cofferdam across the entrance
channel, and in the excavations kept dry by means of pumps. The
foundations under the sills and adjacent side walls are carried down
to a lower level than the rest, and if possible to a water-tight
stratum, to prevent infiltration of water under them owing to the
water-pressure on the upper side of the gates; or sometimes one or two
rows of sheet piling have been driven across the lock under the sills
to an impermeable stratum, to stop any flow. The foundations for the
sills consist usually of concrete deposited in a trench extended out
under the adjoining side walls. The sill, projecting generally about 2
ft. above the adjacent gate floor over which the gates turn, is built
of granite; and the same material is also used for the hollow quoins
in which the heelpost, or pivot, of the dock gates turns, and which,
together with the sills, are exposed to considerable wear. The side
walls of the lock-chamber are very similar in construction to the dock
walls; but they are strengthened against the loss of water-pressure in
front of them when the water is lowered in the chamber by an inverted
arch of masonry, brickwork or concrete, termed an "invert," laid
across the bottom of the chamber along its whole length, against which
the toe of each side wall abuts and effectually prevents any forward
movement. The side walls also, alongside the gates at each end, abut
against a thick level gate floor and apron, and, moreover, are
considerably widened to provide space for the sluiceways and gate
machinery.
The new Florida lock (fig. 20), forming the main entrance through the
new approach harbour and tidal harbour to the Eure dock and other
docks of the port of Havre, is the largest lock hitherto constructed.
It has an available length of chamber between the gates of 805 ft., a
width of 98-1/2 ft., and depths over the sills of 15-3/4 ft. at the
lowest low water of spring tides, 23-1/2 ft. at low water of neap
tides, 35 ft. at high water of neap tides, and 40-1/2 ft. at high
water of spring tides. Owing to the alluvial stratum at the site of
the lock close to the Seine estuary, of which it doubtless at one time
formed part, the foundations for the sill and side walls or heads at
each end of the lock were executed by aid of compressed air. The
foundations for these heads were carried down to an impermeable
stratum by means of two bottomless caissons, filled eventually with
concrete, 213-1/2 ft. long across the lock and 105 ft. wide in the
line of the lock at the upper end, and 206-3/4 ft. long and 116-1/2
ft. wide at the lower end, to a depth of 18 ft. below the sill at the
upper end, and 41 ft. at the lower end, owing to the dip down seawards
and southward of the water-tight stratum. These caissons were provided
for their sinkage with temporary dams of masonry closing the opening
of the lock at the extremities of each caisson, enabling the gates to
be subsequently erected under their shelter. The junctions between the
foundations of the heads and the adjacent foundations were effected by
small movable caissons carried down in recesses provided in the buried
caissons. The connexions with the adjacent quay walls were
accomplished by two supplementary side caissons at the end of each
head; and the north side wall of the lock was founded by means of
seven bottomless caissons sunk by aid of compressed air, on account of
the proximity of the tidal harbour on that side. The south side wall
was founded for a length of about 200 ft. at its western end in an
excavated trench kept dry by pumping; but the greater portion was
founded in a dredged trench in which bearing piles were driven under
water, on which the masonry was built in successive layers, about
3-1/4 ft. thick, in a movable caisson 93-1/2 ft. long and 37-3/4 ft.
wide; whilst a bottomless caisson, left in the work, was employed for
founding about 100 ft. of wall at the eastern end. The bed of concrete
also, 10 ft. thick, forming the floor of the chamber, was carried out
for 82 ft. at the western end in the open air, and the remainder in
the same movable caisson as used for the south wall. Two sluiceways on
each side running the whole length of the lock, differing 6-1/2 ft. in
level, communicate with the lock-chamber through openings in the side
walls, 67-1/4 ft. apart, and provide for the filling and emptying of
the chamber.
[Illustration: FIG. 20.--Florida Lock, Havre Docks, Sections and
Plan.]
[Illustration: FIG. 21.--Wooden Dock Gate.]
[Illustration: FIG. 22.--Iron Segmental Dock Gate.]
[Illustration: FIG. 23.--Straight Iron Dock Gate.]
Dock gates.
The gates closing the entrances and locks at docks are made of wood or
of iron. In iron gates, the heelpost, or a vertical closing strip
attached to the outer side of the gate close to the heelpost, the
meeting-post at the end of each gate closing against each other when
the gates are shut, and the sill piece fitting against the sill are
generally made of wood. Wooden gates consist of a series of horizontal
framed beams, made thicker and put closer together towards the bottom
to resist the water-pressure increasing with the depth, fastened to
the heelpost and meeting-post at the two ends and to intermediate
uprights, and supporting water-tight planking on the inner face (fig.
21). Iron gates have generally an outer as well as an inner skin of
iron plates braced vertically and horizontally by plate-iron ribs, the
horizontal ribs being placed nearer together and the plates made
thicker towards the bottom (figs. 22 and 23). Greenheart is the wood
used for gates exposed to salt water, as it resists the attack of the
teredo in temperate climates. As cellular iron gates are made
water-tight, and have to be ballasted with enough water to prevent
their flotation, or are provided with air chambers below and are left
open to the rising tide on the outer side above, the gates are light
in the water and are easily moved; whereas greenheart gates with their
fastenings are considerably heavier than water, so that a considerable
weight has to be moved when the water is somewhat low in the dock and
the gates therefore only partially immersed. On the other hand, wooden
gates are less liable than iron gates to be seriously damaged if run
into by a vessel.
Dock gates are sometimes made straight, closing against a straight
sill (figs. 20 and 23); and occasionally they are made segmental with
the inner faces forming a continuous circular arc and closing against
a sill corresponding to the outer curves of the gates (fig. 22), or by
means of a projecting sill piece against a straight sill (fig. 21).
More frequently the gates, curved on both faces, meet at an angle
forming a Gothic arch in plan, and close by aid of a projecting piece
against a straight sill, which in the Barry entrance gates is modified
by making the outer faces nearly straight (fig. 19), giving an unusual
width to the centre of the gates. The pressures produced by a head of
water against these gates when closed depends not only on the form of
the gates, but also upon the projection given to the angle of the sill
in proportion to the width of the lock, which is known as the rise,
and is generally placed at a distance along the centre line of the
lock, from a line joining the centres of the heel-posts, of about
one-fourth the width. With straight gates, the stresses consist, first
of a transverse stress due to the water-pressure against the gate,
which increases with the head of water and length of the gate; and
secondly, of a compressive stress along the gate, resulting from the
pressure of the other gate against its meeting-post, which is equal to
half the water-pressure on the gate multiplied by the tangent of half
the angle between the closed gates, varying inversely with the rise.
Though an increase in the rise reduces this stress, it increases the
length of the gate and the transverse stress, and also the length of
the lock. By curving the gates suitably, the transverse stress is
reduced and the longitudinal compressive stress is augmented, till at
last, when the gates form a horizontal segmental arch, the stresses
become wholly compressive and uniform in each horizontal section,
increasing with the depth; and the total stress is equal to the
pressure on a unit of surface multiplied by the radius of curvature.
Though the water-pressure is most uniformly and economically borne by
cylindrical gates, they are longer, and encroach more upon the lines
of quay with their curved recesses than straighter gates; and,
consequently, Gothic-arched gates are often preferred. Straight gates
afford the greatest simplicity in construction.
[Illustration: FIG. 24.--Sliding Caisson.]
[Illustration: FIG. 25.--Ship Caisson.]
Gates in wide entrances or locks are generally supported towards their
outer end by a roller running along a castiron roller-path on the gate
floor (figs. 19, 21 and 22), as well as by the heelpost, fitted over a
steel pivot at the bottom, and tied back against the hollow quoins at
the top by anchor straps and bolts, on which the gate turns. In some
cases, by placing the water ballast in iron gates close to the
heelpost, a roller has been dispensed with, even, for instance, at the
wide entrance at Havre (fig. 23). The gates are opened and closed,
either by an opening and a closing chain for each gate, fastened on
either side and worked from opposite side walls by hydraulic power, or
by a single hydraulic piston or bar hinged to the inner side of each
gate (figs. 19 and 20). The latter system has the advantages of being
simpler and occupying less space in the side walls, of avoiding the
slight loss of available depth over the sill due to the two closing
chains crossing on the sill when the gates are open, and especially of
keeping the gates closed against a swell in exposed sites.
Caissons for docks.
A sliding or rolling caisson is occasionally placed across each end of
a lock in place of a pair of dock gates, being Caissons drawn back
into a recess at the side for opening docks. the lock. As a caisson
chamber has to be covered for over to provide a continuous quay or
roadway on the top, a lowering platform is supplied to enable the
caisson to pass under the small girders spanning the top of the
chamber, or the caisson is sunk down sufficiently (fig. 24). The
caisson is furnished with an air chamber to give it flotation, which
is adjusted by ballast according to the depth of water. The advantages
of a caisson, as compared with a pair of gates, are that the gate
recesses, gate floor, hollow quoins and arrangements for working in
the side walls are dispensed with, so that the lock can be made
shorter, and the work at each head is rendered less complicated. The
caisson itself also serves as a very strong movable bridge, and
therefore is often preferred at dockyards to dock gates. By
improvements in the hauling machinery, a caisson can open or close a
lock as quickly as dock gates; the caissons at Zeebrugge lock, at the
entrance to the Bruges ship canal, are drawn across the lock or into
their chamber by electricity in two minutes. A caisson is specially
useful in cases where there may be a head of water on either side, as
then it takes the place of two pairs of gates pointing in opposite
directions, or for closing an entrance against a current. A caisson,
however, requires a much larger amount of material than a pair of dock
gates, and a considerable width on one side for its chamber, so that
under ordinary conditions gates are generally used at docks.
A ship caisson, so called from its presenting some resemblance in
section to the hull of a vessel, occupies too much time in being
towed, floated into position, and sunk into grooves at the bottom and
sides of an entrance for closing it, and then refloated and towed away
for opening the entrance again, to be used at entrances and locks to
docks (fig. 25). Being, however, simple in construction, taking up
little space, and requiring no chamber or machinery for moving it,
this form of caisson is generally used for closing the entrance to a
graving dock, where it remains for several days in place during the
execution of repairs to a vessel in the dock. A ship caisson only
requires the admission of sufficient water to sink it when in position
across the entrance to a graving dock; and this water has to be pumped
out before it can be floated, and removed to some vacant position in
the neighbouring dock till it is again required. Like a sliding or
rolling caisson, it provides a bridge for crossing over the entrance
of the graving dock when in position.
_Graving Docks._ - Provision has to be made at ports for the repairs of
vessels frequenting them. The simplest arrangement is a timber gridiron,
on which a vessel settles with a falling tide, and can then be inspected
and slightly cleaned and repaired till the tide floats it again.
Inclined slipways are sometimes provided, up which a vessel resting in a
cradle on wheels can be drawn out of the water; and they are also used
for shipbuilding, the vessel when ready for launching being allowed to
slide down them into the water. Graving or dry docks, however, opening
out of a dock, are the usual means provided for enabling the cleaning
and repairs of vessels to be carried out.
[Illustration: FIG. 26.--Plan of Southampton Graving Dock.]
[Illustration: FIG. 27.--Cross Section of Southampton Graving Dock.]
A graving dock consists of an enclosure, surrounded by side walls
stepped on the face, and paved at the bottom with a thick floor
sloping slightly down from the centre to drains along the sides, long
enough to receive the longest vessel likely to come to the port. Its
entrance, at the end adjoining the dock, is just wide enough to admit
the vessel of greatest beam, and deep enough over the sill to receive
the vessel of greatest draught, when light, at the lowest water-level
of the dock (figs. 26 and 27). Graving docks are constructed of
masonry, brickwork or concrete, or formerly in America of timber; they
should be founded on a solid impervious stratum, or, where that is
impracticable, they should be built upon bearing piles and enclosed
within sheet piling, to prevent settlement and the infiltration of
water under pressure below the dock. Keel blocks are laid along the
centre line of the dock, for the keel of the vessel to rest on when
the water is pumped out; and the vessel is further supported on each
side by timber shores supported on the steps or "altars" of the side
walls, which are lined with granite or other hard stone, or blue
bricks, or, when constructed of concrete, with a facing of stronger
concrete, to enable these altars to withstand the wear and shocks to
which they are subjected. Steps and slides are provided at convenient
places at the sides to give access for men and materials to the bottom
of the dock; and culverts and drains lead the water to pumps for
removing the water from the dock when the entrance has been closed,
and to keep it dry whilst a vessel is under repair. Culverts in the
side walls of the entrance enable water to be admitted for filling the
dock to let the vessel out. Graving docks are generally closed by ship
caissons; but where they open direct on to a tidal river, and there is
some exposure, gates are adopted, or sometimes sliding caissons.
The dimensions of graving docks vary considerably with the nature of
the trade and the date of construction; and sometimes an intermediate
entrance is provided to accommodate two smaller vessels. The sizes of
some of the largest graving docks are as follows: Liverpool, Canada
dock, 925-1/2 ft. long, 94 ft. width of entrance, and 29 ft. depth at
the ordinary water-level in the dock; Southampton, 851-3/4 ft. by 90
ft., and 29-1/2 ft. depth at high-water neaps (figs. 26 and 27);
Tilbury, 875 ft. by 70 ft. by 31-1/2 ft.; and Glasgow, 880 ft. by 80
ft. by 26-1/2 ft.
_Floating Dry Docks._--Where there is no site available for a graving
dock, or the ground is very treacherous, floating dry docks, built
originally of wood, but more recently of iron or steel, have
occasionally been resorted to. The first Bermuda dock towed across the
Atlantic in 1869, and the new dock launched in 1902, 545 ft. by 100
ft., are notable examples. Water is admitted into the pontoon at the
bottom to sink the dock sufficiently to admit a vessel at its open
end; and then the water is pumped out of compartments in the pontoon
till the vessel is raised out of water. It is only necessary to find a
sheltered site, with a sufficient depth of water, for conducting the
operations. (L. F. V.-H.)
DOCKET (perhaps from "dock," to curtail or cut short, with the
diminutive suffix _et_, but the origin of the word is obscure; it has
come into use since the 15th century), in law, a brief summary or digest
of a case, or a memorandum of legal decisions; also the alphabetical
list of cases down for trial, or of suits pending. Such cases are said
to be "on the docket." In commercial use, a docket is a warrant from the
custom-house, stating that the duty on goods entered has been paid, or
the label fastened to goods, showing their destination, value, contents,
&c., and, generally, any indorsement on the back of a document, briefly
setting out its contents.
DOCK WARRANT, in law, a document by which the owner of a marine or river
dock certifies that the holder is entitled to goods imported and
warehoused in the docks. In the Factors Act 1889 it is included in the
phrase "document of title" and is defined as any document or writing,
being evidence of the title of any person therein named ... to the
property in any goods or merchandise lying in any warehouse or wharf and
signed or certified by the person having the custody of the goods. It
passes by indorsement and delivery and transfers the absolute right to
the goods described in it. A dock warrant is liable to a stamp duty of
threepence, which may be denoted by an adhesive stamp, to be cancelled
by the person by whom the instrument is executed or issued.
DOCKYARDS. In the fullest meaning of the word, a "dock-yard" (or "navy
yard" in America) is a government establishment where warships of every
kind are built and repaired, and supplied with the men and stores
required to maintain them in a state of efficiency for war. Thus a
dockyard in this extended sense would include slips for building ships,
workshops for manufacturing their machinery, dry docks for repairing
them, stores of arms, ammunition, coal, provisions, &c., with basins in
which they may lie while being supplied with such things, and an
establishment for providing the _personnel_ necessary for manning them.
But in practice few, if any, existing dockyards are of so complete a
nature; many of them, for instance, do not undertake the building of
ships at all, while others are little more than harbours where a ship
may replenish her stores of coal, water and provisions and carry out
minor repairs. Private firms are relied upon for the construction of
many ships down to an advanced stage, the government dockyards
completing and equipping them for commission.
_Great Britain._--Previous to the reign of Henry VIII., the kings of
England had neither naval arsenals nor dockyards, nor any regular
establishment of civil or naval officers to provide ships of war, or to
man them. There are, however, strong evidences of the existence of
dockyards, or of something answering thereto, at very early dates, at
Rye, Shoreham and Winchelsea. In November 1243 the sheriff of Sussex was
ordered to enlarge the house at Rye in which the king's galleys were
kept, so that it might contain seven galleys. In 1238 the keepers of
some of the king's galleys were directed to cause those vessels to be
breamed, and a house to be built at Winchelsea for their safe custody.
In 1254 the bailiffs of Winchelsea and Rye were ordered to repair the
buildings in which the king's galleys were kept at Rye. At Portsmouth
and at Southampton there seem to have been at all times depots for both
ships and stores, though there was no regular dockyard at Portsmouth
till the middle of the 16th century. It would appear, from a curious
poem in Hakluyt's _Collection_ called "The Policie of Keeping the Sea,"
that Littlehampton, unfit as it now is, was the port at which Henry
VIII. built
"his great _Dromions_
Which passed other great shippes of the commons."
The "dromion," "dromon," or "dromedary" was a large warship, the
prototype of which was furnished by the Saracens. Roger de Hoveden,
Richard of Devizes and Peter de Longtoft celebrate the struggle which
Richard I., in the "Trench the Mer," on his way to Palestine, had with a
huge dromon,--"a marvellous ship! a ship than which, except Noah's ship,
none greater was ever read of." This vessel had three masts, was very
high out of the water, and is said to have had 1500 men on board. It
required the united force of the king's galleys, and an obstinate fight,
to capture the dromon.
The foundation of a regular British navy, by the establishment of
dockyards, and the formation of a board, consisting of certain
commissioners for the management of its affairs, was first laid by Henry
VIII., and the first dockyard erected during his reign was that of
Woolwich. Those of Portsmouth, Deptford, Chatham and Sheerness followed
in succession. Plymouth was founded by William III. Pembroke was
established in 1814, a small yard having previously existed at Milford.
The most important additions yet made at any one period to the dockyard
and harbour works required to meet the necessities of the British fleet
were those sanctioned by the Naval Works Acts of 1895 and subsequent
years, the total estimated cost, as stated in the act of 1899, being
over 23-1/2 millions sterling. The works proposed under these acts were
classified under three heads, viz. (a) the enclosure and defence of
harbours against torpedo attacks; (b) adapting naval ports to the
present needs of the fleet; (c) naval barracks and hospitals. Under the
first heading were included the defensive harbours at Portland, Dover
and Gibraltar. Under heading (b) were included the deepening of harbours
and approaches, the dockyard extensions at Gibraltar, Keyham
(Devonport), Simons Bay, and Hong-Kong, with sundry other items. Under
heading (c) were included the naval barracks at Chatham, Portsmouth and
Keyham; the naval hospitals at Chatham, Haslar and Haulbowline; the
colleges at Keyham and Dartmouth; and other items.
Great Britain possesses dockyards at Portsmouth, Devonport, Chatham,
Malta and Gibraltar, each in charge of an admiral-superintendent, and at
Sheerness and Pembroke in charge of a captain-superintendent, together
with establishments at Ascension, Bermuda, Simons Town (Cape of Good
Hope), Queenstown (Haulbowline); Hong-Kong, Portland, Sydney and
Weihaiwei. The Indian Government has dockyards at Bombay and Calcutta.
The medical establishments include Ascension, Bermuda, Cape of Good
Hope, Chatham, Dartmouth, Deal, Gibraltar, Haslar, Haulbowline,
Hong-Kong, Malta, Osborne, Plymouth, Portland, Portsmouth, Sheerness,
Sydney, Yarmouth, Yokohama and Weihaiwei.
The arrangements for the administrative control of the dockyards have
varied with those adopted for the regulation of the navy as a whole.
(See ADMIRALTY ADMINISTRATION; and NAVY: _History_.) At the present
time, whether at home or abroad, they lie within the province of the
controller of the navy (the third lord of the board of admiralty); and
the director of dockyards, whose office, replacing that of surveyor of
dockyards was created in December 1885, is responsible to the
controller for the building of ships, boats, &c., in dockyards, and for
the maintenance and repair of ships and boats, and of all steam
machinery in ships, boats, dockyards and factories. The director of
naval construction, who is also deputy-controller, is responsible, not
only for the design of ships, but for their construction, in the sense
that he approves great numbers of working drawings of structural parts
prepared at the dockyards. But the director of dockyards is the
admiralty official under whose instructions the work goes on, involving
the employment and supervision of an army of artisans and labourers.
Instructions, therefore, emanate from the admiralty, but the details lie
with the dockyard officials, and in practice there is a considerable
decentralization of duties.
The chief function of a dockyard is the building and maintaining of
ships in efficiency. The constructive work is carried out under the care
of the chief constructor of the yard, in accordance with plans sent down
from the admiralty. The calculations for displacement, involving the
draught of water forward and aft, have already been made, and, in order
to ensure accuracy in the carrying out of the design, an admirable
system has been devised for weighing everything that is built into the
new ships or that goes on board; and it is astonishing how very closely
the actual displacement approximates to that which was intended,
particularly when the tendency of weights to increase, in perfecting a
ship for commission, is considered.
The ship having been built to her launching weight, the duty of putting
her into the water devolves upon the chief constructor of the yard, and
failures in this matter are so extremely rare that it may almost be said
they do not occur. As soon as the ship is water-borne the responsibility
falls upon the king's harbour master, who has charge of her afloat and
of moving her into the fitting basins. When the ship has been brought
alongside the wharf, the responsibility of the chief constructor of the
yard is resumed, and the ship is carried forward to completion by the
affixing of armour plating (if that has not been done before launching),
the mounting of guns, the instalment of engines, boilers, and electrical
and hydraulic gear, and the fitting of cabins for officers, mess places
for men, and storerooms, and a vast volume of other work unnecessary to
be specified. In regard to the complicated details of guns and
torpedoes, the captains of the gunnery and torpedo schools have a
function of supervision. The captain of the fleet reserve also closely
watches the work, because, when the heads of all departments have
reported the ship to be ready, she has to be inspected by the
commander-in-chief at the port, and then passed into the fleet reserve
as ready for sea, and there the captain of the fleet reserve is
responsible for her efficiency. Other important officers of a dockyard
are the chief engineer; the superintendent civil engineer, who has
charge of the work involved in keeping all buildings, docks, basins,
caissons, roads, &c., in repair; the naval store officer, who has charge
of most of the stores in the dockyard; and the cashier of the yard,
whose name sufficiently expresses his duties.
The system of conducting business at the dockyards is analogous to that
which prevails at the admiralty. There is personal communication between
the officers responsible for the work, and facilities are afforded for
coming to rapid decisions upon matters that are in hand, and the
operations are conducted with an ease which contributes much to
efficiency. In 1844 the custom was introduced of all the principal
officers of the dockyard meeting at the superintendent's office at 9.30
A.M. every day, to hear the orders from the admiralty and discuss the
work of the day. But this system of "readings" was abolished at the
beginning of 1906, the naval establishments inquiry committee
considering that the assembling of the officials was unnecessary since
the communications after reception are copied and sent to the
departments concerned.
The police force necessary in a dockyard is in some cases supplied from
the London metropolitan police, and is under the orders of the
superintendent of the yard for duties connected with it, and under the
commissioner of police for the discipline and disposition of the force.
The charges are, of course, paid by the admiralty, and the system
answers well.
_United States._--The shore stations under control of the Navy
Department (see also ADMIRALTY ADMINISTRATION), and collectively known
as naval stations, are under different names according to their nature.
Of those called _Navy Yards_, and intended for the general purpose of
sources of supply and for repairs of ships, there are within the United
States eight in number. Two of them are on the Pacific coast, situated
on Puget Sound, at Bremerton, Washington; and at Mare Island, near San
Francisco. The other six are on the Atlantic coast, and are situated at
Portsmouth, N.H.; Boston, Mass.; Brooklyn, N.Y.; Philadelphia, Pa.;
Washington, D.C.; and Norfolk, Va. There are also naval stations at Port
Royal and Charleston, S.C.; Key West and Pensacola, Fla.; New Orleans,
La.; Guantanamo, Cuba; Culebra and San Juan, Porto Rico; Honolulu, H.I.;
Cavite, P.I.; Tutuila, Samoa; and Island of Guam, in the Ladrones
Islands. The floating dock Dewey, having a lifting capacity of 18,500
gross tons with a free-board of 2 ft., was stationed in the Philippine
Islands in 1906.
Besides these, there are important naval stations established for
special purposes, which in some cases are also available for ports of
supply and for repairs. These are: the U.S. Naval Academy, Annapolis,
Md., for the instruction of naval cadets; the training stations at
Newport, R.I., and Yerba Buena Island, Cal., for the instruction of
apprentices; the proving ground at Indian Head, Md., on the Potomac
river, where all government-built ordnance is tested; the War College at
Newport, R.I., for the instruction of officers; the torpedo station at
Newport, for the instruction of officers and men in torpedoes,
electricity and submarine diving; the naval observatory at Washington;
and the marine post at Sitka, Alaska. Coaling depots have been
established at Honolulu, Pago Pago, Samoan Islands, and at Manila, P.I.
Naval hospitals are located at the Portsmouth, Boston, New York,
Philadelphia, Washington, Norfolk and Mare Island yards; at Las Animas,
Colo.; at Newport, R.I.; Canacao, P.I.; Sitka, Alaska; and Yokohama,
Japan.
The commandant of a navy yard and station, who is usually a
rear-admiral, is its commander-in-chief. His official assistants are
called heads of departments. The captain of the yard, who is next in
succession to command, has general charge of the water front and the
ships moored there, and of the police of the navy yard; it is his duty
to keep the commandant informed as to the nature and efficiency of all
work in progress. The equipment officer has charge of anchors, chains,
rigging, sails and the electric generating plant. The other heads of
departments are the ordnance officer, the naval constructor, the
engineering officer, the general storekeeper, the paymaster of the yard,
the surgeon and the civil engineer. The clerks and draughtsmen employed
by these officers are appointed under civil service rules, and their
employment is continuous so long as funds are available. The foremen are
selected by competitive examination, and their number is fixed. In the
employment of mechanics and labourers, veterans are given preference,
after which follow persons previously employed who have displayed
especial efficiency and good conduct. The rates of wages are determined
semi-annually by a board of officers, who ascertain the wages paid by
private establishments in the vicinity of the navy yard. Eight hours
constitute the legal work day. When emergencies necessitate longer hours
the workmen are paid at the ordinary rate plus 50%.
The nature and extent of work to be performed upon naval vessels is
determined by the secretary of the navy; the commandant then issues the
necessary orders. The material required is obtained by a system of
requisitions, which provide for the purchase from the lowest bidder
after open competition. Heads of departments initiate the purchase of
materials which are peculiar to their own work; ordinary commercial
articles, however, are usually carried in a special stock called the
"Naval Supply Fund," which may be drawn upon by any head of department.
All materials are inspected, both as to quantity and quality, by a board
of inspectors consisting of three officers.
_France._--The French coast is divided into five naval
arrondissements, which have their headquarters at the five naval ports
of which Cherbourg, Brest and Toulon are the most important, Lorient
and Rochefort being of lesser degree. All are building and fitting-out
yards. Corsica, which has naval stations at Ajaccio, Porto Vecchio,
Bonifacio and other places, is a dependency of the arsenal at Toulon.
On the African coast there are docking facilities in Algeria. Bizerta,
the Tunisian port, has been made a naval base by the deepening and
fortifying of the canal which is the approach to the inner lake. There
are arsenals also at Saigon and Hai-phong, and an establishment at
Diego Suarez.
The subsidiary establishments in France are the gun foundry at Ruelle;
the steel and iron works at Guerigny, where anchors, chains and
armour-plate are made; and the works at Indret, on an island in the
lower Loire, where machinery is constructed. There are many private
shipbuilding establishments in the country, the most important being
the Forges et Chantiers de la Mediterranee at La Seyne, on the lesser
roadstead at Toulon where many French and foreign warships of the
largest classes have been built. The same company has a building yard
at Havre. Other establishments are the Ateliers et Chantiers de la
Loire, at Saint Nazaire; the Normand Yard, at Havre; and the Chantiers
de la Gironde, near Bordeaux.
Each of the arrondissements above mentioned is divided into
sous-arrondissements, having their centres in the great commercial
ports, but this arrangement is purely for the embodiment of the men of
the Inscription Maritime, and has nothing to do with the dockyards as
naval arsenals. In each arrondissement the vice-admiral, who is naval
prefect, is the immediate representative of the minister of marine,
and has full direction and command of the arsenal, which is his
headquarters. He is thus commander-in-chief, as also
governor-designate for time of war, but his authority does not extend
to ships belonging to organized squadrons or divisions. The naval
prefect is assisted by a rear-admiral as chief of the staff (except at
Lorient and Rochefort, where the office is filled by a captain), and a
certain number of officers, the special functions of the chief of the
staff having relation principally to the efficiency and _personnel_ of
the fleet, while the "major-general," who is usually a rear-admiral,
is concerned chiefly with the _materiel_. There are also directors of
stores, of naval construction, of the medical service and of the
submarine defences (which are concerned with torpedoes, mines and
torpedo-boats), as well as of naval ordnance and works. The prefect
directs the operations of the arsenal, and is responsible for its
efficiency and for that of the ships which are there in reserve. In
regard to the constitution and maintenance of the naval forces, the
administration of the arsenals is divided into three principal
departments, the first concerned with naval construction, the second
with ordnance, including gun-mountings and small-arms, and the third
with the so-called submarine defences, dealing with all torpedo
_materiel_.
_Germany._--With the expansion of the German navy considerable
additions have been made to the two principal dockyards. These are
Wilhelmshaven, the naval headquarters on the North Sea, and Kiel, the
headquarters on the Baltic, Danzig being an establishment of lesser
importance, and Kiao-chau an undeveloped base in the Shantung
peninsula, China. The chief official at each home dockyard is the
superintendent (_Oberwerftdirektor_), who is a rear-admiral or senior
captain directly responsible to the naval secretary of state. Under
the superintendent's orders are the chief of the Ausrustung
department, or captain of the fleet reserve, the directors of
ordnance, torpedoes, navigation, naval construction, engineering and
harbour works, with some other officers. The chiefs of the
constructive and engineering departments are responsible for the
building of ships and machinery, and for the maintenance of the hulls
and machinery of existing vessels; while the works department has
charge of all work on the quays, docks, &c., in the dockyard and port.
A great advance has been made in increasing the efficiency and
capabilities of the imperial dockyards by introducing a system of
continuous work in the building of new ships and effecting alterations
in others, and German material is exclusively used. The Schichau Works
at Elbing and Danzig, the Vulkan Yard at Bredow, near Stettin, the
Weser Company at Bremen, and the establishment of Blohm and Voss at
Hamburg, are important establishments which have built many vessels
for the German navy, as well as for foreign states.
_Italy._--The principal Italian state dockyards are Spezia, Naples and
Venice, the first named being by far the most important. It covers an
area, including the water spaces, of 629 acres, and there are five dry
docks, three being 433 ft. long and 105 ft. wide, and two 361 ft. long
and 98 ft. 6 in. wide. The dockyard is very completely equipped with
machinery of the best British, German and Italian makes, and it has
built several of the finest Italian ships. The number of hands
employed in the yard averages 4000. There are two building slips, and
for smaller vessels there are two in the neighbouring establishment of
San Bartolommeo (which is the headquarters for submarine mining), and
one at San Vito, where is a Government gun factory. Castellammare di
Stabia is subsidiary to Naples. A large dry dock has been built at
Taranto. There is a small naval establishment at Maddalena Island on
the Strait of Bonifacio. The Italian Government has no gun or torpedo
factories, nearly all the ordnance coming from the Armstrong factory
at Pozzuoli near Naples, and the torpedoes from the Schwarzkopf
factory at Venice, while armour-plates are produced at the important
works at Terni. Machinery is supplied by the firms of Ansaldo, Odero,
Orlando, Guppy & Hawthorn and Pattison. The three establishments
first named have important shipbuilding yards, and have constructed
vessels for the Italian and foreign navies. The Orlando Yard at
Leghorn is Government property, but is leased by the firm, and
possesses five building slips.
_Austria-Hungary._--The naval arsenal is on the well-protected harbour
of Pola, in Istria, which is the headquarters of the national navy,
and includes establishments of all kinds for the maintenance of the
fleet. There are large building and docking facilities, and a number
of warships have been built there. There is a construction yard also
at Trieste. A new coaling and torpedo station is at Teodo, large
magazines and stores are at Vallelunga, and the mining establishment
is at Ficella. The shipbuilding branch of the navy is under the
direction of a chief constructor (_Oberster-Ingenieur_), assisted by
seven constructors, of whom two are of the first class. The
engineering and ordnance branches are similarly organized.
_Spain._--The Spanish dockyards are of considerable antiquity, but of
diminishing importance. There is an establishment at Ferrol, another
at Cartagena, and a third at Cadiz. They are well equipped in all
necessary respects, but are not provided with continuous work. A
recent arrangement is the specialization of the yards, Ferrol being
designed for larger, and Carthagena for smaller, building work. The
ordnance establishment is at Carraca.
_Russia._--In Russia the naval ports are of two classes. The most
important are Kronstadt, St Petersburg and Nikolayev. Of lesser
importance are Reval, Sveaborg, Sevastopol, Batum, Baku and
Vladivostok. The administration of the larger ports, except St
Petersburg, which is under special regulations, is in the hands of
vice-admirals, who are commanders-in-chief, while the smaller ports
are under the direction of rear-admirals. All are directly under the
minister of marine, except that the Black Sea ports and Astrabad, on
the Caspian, are subordinate to the commander-in-chief at Nikolayev.
Sevastopol has grown in importance, and become mainly a naval harbour,
the commercial harbour being removed to Theodosia. The Russian
government has also proposed to remodel the harbour works at St
Petersburg and Kronstadt. The Emperor Alexander III. Port at Libau, on
the Baltic, is in a region less liable to be icebound in the winter.
There are no strictly private yards for the building of large vessels
in Russia, except that of the Black Sea Company at Nikolayev. Messrs
Creighton build torpedo-boats at Abo in Finland, and the admiralty has
steel works at Ijora, where some torpedo-boats have been built. Other
ordnance and steel works are at Obukhov and Putilov.
_Japan._--The principal Japanese dockyard, which was established by
the Shogunate in 1866, is Yokosuka. French naval constructors and
engineers were employed, and several wooden ships were built. The
Japanese took the administration into their own hands in 1875, and
built a number of vessels of small displacement in the yard. The limit
of size was about 5000 tons, but the establishment has been enlarged
so that vessels of the first class may be built there. There is a
first-class modern dry dock which will take the largest battleship.
Shipbuilding would be undertaken to a larger extent but for the fact
that nearly all material has to come from abroad. Down to 1905 all the
important vessels of the Japanese navy were built in Great Britain,
France, Germany and the United States, but at the end of that year a
first-class cruiser of 13,500 tons (the "Tsukuba") was launched from
the important yard at Kure. There are other yards at Sassebo and
Maisuru.
DOCTOR (Lat. for "teacher"), the title conferred by the highest
university degree. Originally there were only two degrees, those of
bachelor and master, and the title doctor was given to certain masters
as a merely honorary appellation. The process by which it became
established as a degree superior to that of master cannot be clearly
traced. At Bologna it seems to have been conferred in the faculty of law
as early as the 12th century. Paris conferred the degree in the faculty
of divinity, according to Antony Wood, some time after 1150. In England
it was introduced in the 13th century; and both in England and on the
continent it was long confined to the faculties of law and divinity.
Though the word is so commonly used as synonymous with "physician," it
was not until the 14th century that the doctor's degree began to be
conferred in medicine. The tendency since has been to extend it to all
faculties; thus in Germany, in the faculty of arts, it has replaced the
old title of _magister_. The doctorate of music was first conferred at
Oxford and Cambridge.
_Doctors of the Church_ are certain saints whose doctrinal writings have
obtained, by the universal consent of the Church or by papal decree, a
special authority. In the case of the great schoolmen a characteristic
qualification was added to the title doctor, e.g. "angelicus" (Aquinas),
"mellifluus" (Bernard). The doctors of the Church are: for the East, SS.
Athanasius, Gregory of Nazianzus, Basil the Great, John Chrysostom; for
the West, SS. Hilary, Ambrose, Jerome, Augustine, Gregory the Great,
Anselm, Bernard, Bonaventura and Thomas Aquinas. To these St Alphonso
dei Liguori was added by Pope Pius IX.
DOCTORS' COMMONS, the name formerly applied to a society of
ecclesiastical lawyers in London, forming a distinct profession for the
practice of the civil and canon laws. Some members of the profession
purchased in 1567 a site near St Paul's, on which at their own expense
they erected houses (destroyed in the great fire, but rebuilt in 1672)
for the residence of the judges and advocates, and proper buildings for
holding the ecclesiastical and admiralty courts. In 1768 a royal charter
was obtained by virtue of which the then members of the society and
their successors were incorporated under the name and title of "The
College of Doctors of Law exercent in the Ecclesiastical and Admiralty
Courts." The college consisted of a president (the dean of Arches for
the time being) and of those doctors of law who, having regularly taken
that degree in either of the universities of Oxford or Cambridge, and
having been admitted advocates in pursuance of the rescript of the
archbishop of Canterbury, were elected fellows in the manner prescribed
by the charter. There were also attached to the college thirty-four
proctors, whose duties were analogous to those of solicitors. The judges
of the archiepiscopal courts were always selected from this college. By
the Court of Probate Act 1857 the college was empowered to sell its real
and personal estate and to surrender its charter, and it was enacted
that on such surrender the college should be dissolved and the property
thereof belong to the then existing members as tenants in common for
their own use and benefit. The college was accordingly dissolved, and
the various ecclesiastical courts which sat at Doctors' Commons (the
Court of Arches, the Prerogative Court, the Faculty Court and the Court
of Delegates) are now open to the whole bar.
DOCTRINAIRES, the name given to the leaders of the moderate and
constitutional Royalists in France after the second restoration of Louis
XVIII. in 1815. The name, as has often been the case with party
designations, was at first given in derision, and by an enemy. In 1816
the _Nain jaune refugie_, a French paper published at Brussels by
Bonapartist and Liberal exiles, began to speak of M. Royer-Collard as
the "doctrinaire" and also as _le pere Royer-Collard de la doctrine
chretienne_. The _peres de la doctrine chretienne_, popularly known as
the "doctrinaires," were a French religious order founded in 1592 by
Cesar de Bus. The choice of a nickname for M. Royer-Collard does credit
to the journalistic insight of the contributors to the _Nain jaune
refugie_, for he was emphatically a man who made it his business to
preach a doctrine and an orthodoxy. The popularity of the name and its
rapid extension to M. Royer-Collard's colleagues is the sufficient proof
that it was well chosen and had more than a personal application. These
colleagues came, it is true, from various quarters. The duc de Richelieu
and M. de Serre had been Royalist _emigres_ during the revolutionary and
imperial epoch. MM. Royer-Collard himself, Laine, and Maine de Biran had
sat in the revolutionary Assemblies. MM. Pasquier, Beugnot, de Barante,
Cuvier, Mounier, Guizot and Decazes had been imperial officials. But
they were closely united by political principle, and also by a certain
similarity of method. Some of them, notably Guizot and Maine de Biran,
were theorists and commentators on the principles of government. M. de
Barante was an eminent man of letters. All were noted for the doctrinal
coherence of their principles and the dialectical rigidity of their
arguments. The object of the party as defined by M. (afterwards the duc)
Decazes was to "nationalize the monarchy and to royalize France." The
means by which they hoped to attain this end were a loyal application of
the charter granted by Louis XVIII., and the steady co-operation of the
king with the moderate Royalists to defeat the extreme party known as
the Ultras, who aimed at the complete undoing of the political and
social work of the Revolution. The Doctrinaires were ready to allow the
king a large discretion in the choice of his ministers and the direction
of national policy. They refused to allow that ministers should be
removed in obedience to a hostile vote in the chamber. Their ideal in
fact was a combination of a king who frankly accepted the results of
the Revolution, and who governed in a liberal spirit, with the advice of
a chamber elected by a very limited constituency, in which men of
property and education formed, if not the whole, at least the very great
majority of the voters. Their views were set forth by Guizot in 1816 in
his treatise _Du gouvernement representatif et de l'etat actuel de la
France._ The chief organs of the party in the press were the
_Independent_, renamed the _Constitutionnel_ in 1817, and the _Journal
des debats_. The supporters of the Doctrinaires in the country were
chiefly ex-officials of the empire,--who believed in the necessity for
monarchical government but had a lively memory of Napoleon's tyranny and
a no less lively hatred of the _ancien regime_--merchants, manufacturers
and members of the liberal professions, particularly the lawyers. The
history of the Doctrinaires as a separate political party began in 1816
and ended in 1830. In 1816 they obtained the co-operation of Louis
XVIII., who had been frightened by the violence of the Ultras in the
_Chambre introuvable_ of 1815. In 1830 they were destroyed by Charles X.
when he took the Ultra prince de Polignac as his minister and entered on
the conflict with Liberalism in France which ended in his overthrow.
During the revolution of 1830 the Doctrinaires became absorbed in the
Orleanists, from whom they had never been separated on any ground of
principle (see FRANCE: _History_).
The word "doctrinaire" has become naturalized in English terminology, as
applied, in a slightly contemptuous sense, to a theorist, as
distinguished from a practical man of affairs.
See Duvergier de Hauranne, _Histoire du gouvernement parlementaire en
France_ (Paris, 1857-1871), vol. iii.
DOCUMENT, strictly, in law, that which can serve as evidence or proof,
and is written or printed, or has an inscription or any significance
that can be "read"; thus a picture, authenticated photograph, seal or
the like would furnish "documentary evidence." More generally the word
is used for written or printed papers that provide information or
evidence on a subject. The Latin _documentum_, from which the word is
derived, meant, in classical times, a lesson, example or proof
(_docere_, to teach), and only in medieval Latin came to be applied to
an _instrumentum_, or record in writing. The classical Latin use is
found in English; thus Jeremy Taylor (Works, ed. 1835, i. 815) speaks of
punishment being a "single and sudden document if instantly inflicted"
(see DIPLOMATIC; and EVIDENCE).
DODD, WILLIAM (1729-1777), English divine, was born at Bourne in
Lincolnshire in May 1729. He was admitted a sizar of Clare Hall,
Cambridge, in 1745, and took the degree of B.A. in 1750, being fifteenth
wrangler. On leaving the university he married a young woman of a more
than questionable reputation, whose extravagant habits helped to ruin
him. In 1751 he was ordained deacon, and in 1753 priest, and he soon
became a popular and celebrated preacher. His first preferment was the
lectureship of West-Ham and Bow. In 1754 he was also chosen lecturer of
St Olave's, Hart Street; and in 1757 he took the degree of M.A. at
Cambridge, subsequently becoming LL.D. He was a strenuous supporter of
the Magdalen hospital, founded in 1758, and soon afterwards became
preacher at the chapel of that charity. In 1763 he obtained a prebend at
Brecon, and in the same year he was appointed one of the king's
chaplains,--soon after which the education of Philip Stanhope,
afterwards earl of Chesterfield, was committed to his care. In 1768 he
had a fashionable congregation and was held in high esteem, but
indiscreet ambition led to his ruin. On the living of St George's,
Hanover Square, becoming vacant in 1774, Mrs Dodd wrote an anonymous
letter to the wife of the lord chancellor, offering three thousand
guineas if, by her assistance, Dodd were promoted to the benefice. This
letter having been traced, a complaint was immediately made to the king,
and Dodd was dismissed from his office as chaplain. After residing for
some time at Geneva and Paris, he returned to England in 1776. He still
continued to exercise his clerical functions, but his extravagant habits
soon involved him in difficulties. To meet his creditors he forged a
bond on his former pupil Lord Chesterfield for L4200, and actually
received the money. He was detected, committed to prison, tried at the
Old Bailey, found guilty, and sentenced to death; and, in spite of
numerous applications for mercy, he was executed at Tyburn on the 27th
of June 1777. Samuel Johnson was very zealous in pleading for a pardon,
and a petition from the city of London received 23,000 signatures. Dr
Dodd was a voluminous writer and possessed considerable abilities, with
but little judgment and much vanity. He wrote one or two comedies, and
his _Beauties of Shakespeare_, published in 1752, was long a well-known
work; while his _Thoughts in Prison_, a poem in blank verse, written
between his conviction and execution, naturally attracted much
attention. He published a large number of sermons and other theological
works, including a _Commentary on the Bible_ (1765-1770). A list of his
fifty-five writings and an account of the writer is included in the
_Thoughts in Prison_.
See also P. Fitzgerald, _A Famous Forgery_ (1865).
DODDER (Frisian _dodd_, a bunch; Dutch _dot_, ravelled thread), the
popular name of the annual, leafless, twining, parasitic plants forming
the genus _Cuscuta_, formerly regarded as representing a distinct
natural order Cuscutaceae, but now generally ranked as a tribe of the
natural order Convolvulaceae. The genus contains nearly 100 species and
is widely distributed in the temperate and warmer parts of the earth.
The slender thread-like stem is white, yellow, or red in colour, bears
no leaves, and attaches itself by suckers to the stem or leaves of some
other plant round which it twines and from which it derives its
nourishment. It bears clusters of small flowers with a four- or
five-toothed calyx, a cup-shaped corolla with four or five stamens
inserted on its tube, and sometimes a ring of scales below the stamens;
the two-celled ovary becomes when ripe a capsule splitting by a ring
just above the base. The seeds are angular and contain a thread-like
spirally coiled embryo which bears no cotyledons. On coming in contact
with the living stem of some other plant the seedling dodder throws out
a sucker, by which it attaches itself and begins to absorb the sap of
its foster-parent; it then soon ceases to have any connexion with the
ground. As it grows, it throws out fresh suckers, establishing itself
firmly on the host-plant (fig. 2). After making a few turns round one
stem the dodder finds its way to another, and thus it continues twining
and branching till it resembles "fine, closely-tangled, wet catgut." The
injury done to flax, clover, hop and bean crops by species of dodder is
often very great. _C. europaea_, the greater dodder (fig. 1) is found
parasitic on nettles, thistles, vetches and the hop; _C. Epilinum_, on
flax; _C. Epithymum_, on furze, ling and thyme. _C. Trifolii_, the
Clover Dodder, is perhaps a subspecies of the last mentioned.
[Illustration: FIG. 1.--_Cuscuta europaea_, Dodder.
1. Flower removed from 2, Calyx.
3. Ovary cut across.
4. Fruit enveloped by a persistent corolla.
5. Seed.
6. Embryo.