[1] The sign of M is shown by the arrow-heads in fig. 19, for which,
with y downwards,
d^2y
EI ---- + M = 0.
dx^2
[2] The figure is drawn for a case where the bending moment has the
same sign throughout.
[3] M0 is taken to have, as it obviously has, the opposite sense to
that shown in fig. 19.
[4] The line joining the points of contact must be normal to the
planes.
ELATERITE, also termed ELASTIC BITUMEN and MINERAL CAOUTCHOUC, a mineral
hydrocarbon, which occurs at Castleton in Derbyshire, in the lead mines
of Odin and elsewhere. It varies somewhat in consistency, being
sometimes soft, elastic and sticky; often closely resembling
india-rubber; and occasionally hard and brittle. It is usually dark
brown in colour and slightly translucent. A substance of similar
physical character is found in the Coorong district of South Australia,
and is hence termed coorongite, but Prof. Ralph Tate considers this to
be a vegetable product.
ELATERIUM, a drug consisting of a sediment deposited by the juice of the
fruit of _Ecballium Elaterium_, the squirting cucumber, a native of the
Mediterranean region. The plant, which is a member of the natural order
Cucurbitaceae, resembles the vegetable marrow in its growth. The fruit
resembles a small cucumber, and when ripe is highly turgid, and
separates almost at a touch from the fruit stalk. The end of the stalk
forms a stopper, on the removal of which the fluid contents of the
fruit, together with the seeds, are squirted through the aperture by the
sudden contraction of the wall of the fruit. To prepare the drug the
fruit is sliced lengthwise and slightly pressed; the greenish and
slightly turbid juice thus obtained is strained and set aside; and the
deposit of elaterium formed after a few hours is collected on a linen
filter, rapidly drained, and dried on porous tiles at a gentle heat.
Elaterium is met with in commerce in light, thin, friable, flat or
slightly incurved opaque cakes, of a greyish-green colour, bitter taste
and tea-like smell.
The drug is soluble in alcohol, but insoluble in water and ether. The
official dose is 1/10-1/2 grain, and the British pharmacopeia directs
that the drug is to contain from 20 to 25% of the active principle
elaterinum or elaterin. A resin in the natural product aids its action.
Elaterin is extracted from elaterium by chloroform and then precipitated
by ether. It has the formula C_20H_28O5. It forms colourless scales
which have a bitter taste, but it is highly inadvisable to taste either
this substance or elaterium. Its dose is 1/40-1/10 grain, and the
British pharmacopeia contains a useful preparation, the Pulvis Elaterini
Compositus, which contains one part of the active principle in forty.
The action of this drug resembles that of the saline aperients, but is
much more powerful. It is the most active hydragogue purgative known,
causing also much depression and violent griping. When injected
subcutaneously it is inert, as its action is entirely dependent upon its
admixture with the bile. The drug is undoubtedly valuable in cases of
dropsy and Bright's disease, and also in cases of cerebral haemorrhage,
threatened or present. It must not be used except in urgent cases, and
must invariably be employed with the utmost care, especially if the
state of the heart be unsatisfactory.
ELBA (Gr. [Greek: Aithalia]; Lat. _Ilva_), an island off the W. coast of
Italy, belonging to the province of Leghorn, from which it is 45 m. S.,
and 7 m. S.W. of Piombino, the nearest point of the mainland. Pop.
(1901) 25,043 (including Pianosa). It is about 19 m. long, 6-1/2 m.
broad, and 140 sq. m. in area; and its highest point is 3340 ft. (Monte
Capanne). It forms, like Giglio and Monte Cristo, part of a sunken
mountain range extending towards Corsica and Sardinia.
The oldest rocks of Elba consist of schist and serpentine which in the
eastern part of the island are overlaid by beds containing Silurian and
Devonian fossils. The Permian may be represented, but the Trias is
absent, and in general the older Palaeozoic rocks are overlaid directly
by the Rhaetic and Lias. The Liassic beds are often metamorphosed and
the limestones contain garnet and wollastonite. The next geological
formation which is represented is the Eocene, consisting of nummulitic
limestone, sandstone and schist. The Miocene and Pliocene are absent.
The most remarkable feature in the geology of Elba is the extent of the
granitic and ophiolitic eruptions of the Tertiary period. Serpentines,
peridotites and diabases are interstratified with the Eocene deposits.
The granite, which is intruded through the Eocene beds, is associated
with a pegmatite containing tourmaline and cassiterite. The celebrated
iron ore of Elba is of Tertiary age and occurs indifferently in all the
older rocks. The deposits are superficial, resulting from the opening
out of veins at the surface, and consist chiefly of haematite. These
ores were worked by the ancients, but so inefficiently that their
spoil-heaps can be smelted again with profit. This process is now gone
through on the island itself. The granite was also quarried by the
Romans, but is not now much worked.
Parts of the island are fertile, and the cultivation of vines, and the
tunny and sardine fishery, also give employment to a part of the
population. The capital of the island is Portoferraio--pop. (1901)
5987--in the centre of the N. coast, enclosed by an amphitheatre of
lofty mountains, the slopes of which are covered with villas and
gardens. This is the best harbour, the ancient _Portus Argous_. The town
was built and fortified by Cosimo I. in 1548, who called it Cosmopolis.
Above the harbour, between the forts Stella and Falcone, is the palace
of Napoleon I., and 4 m. to the S.W. is his villa; while on the N. slope
of Monte Capanne is another of his country houses. The other villages in
the island are Campo nell' Elba, on the S. near the W. end, Marciana and
Marciana Marina on the N. of the island near the W. extremity, Porto
Longone, on the E. coast, with picturesque Spanish fortifications,
constructed in 1602 by Philip III.; Rio dell' Elba and Rio Marina, both
on the E. side of the island, in the mining district. At Le Grotte,
between Portoferraio and Rio dell' Elba, and at Capo Castello, on the
N.E. of the island, are ruins of Roman date.
Elba was famous for its mines in early times, and the smelting furnaces
gave it its Greek name of [Greek: A'thalia] ("soot island"). In Roman
times, and until 1900, however, owing to lack of fuel, the smelting was
done on the mainland. In 453 B.C. Elba was devastated by a Syracusan
squadron. From the 11th to the 14th century it belonged to Pisa, and in
1399 came under the dukes of Piombino. In 1548 it was ceded by them to
Cosimo I. of Florence. In 1596 Porto Longone was taken by Philip III. of
Spain, and retained until 1709, when it was ceded to Naples. In 1802 the
island was given to France by the peace of Amiens. On Napoleon's
deposition, the island was ceded to him with full sovereign rights, and
he resided there from the 5th of May 1814 to the 26th of February 1815.
After his fall it was restored to Tuscany, and passed with it to Italy
in 1860.
See Sir R. Colt Hoare, _A Tour through the Island of Elba_ (London,
1814).
ELBE (the _Albis_ of the Romans and the _Labe_ of the Czechs), a river
of Germany, which rises in Bohemia not far from the frontiers of
Silesia, on the southern side of the Riesengebirge, at an altitude of
about 4600 ft. Of the numerous small streams (Seifen or Flessen as they
are named in the district) whose confluent waters compose the infant
river, the most important are the Weisswasser, or White Water, and the
Elbseifen, which is formed in the same neighbourhood, but at a little
lower elevation. After plunging down the 140 ft. of the Elbfall, the
latter stream unites with the steep torrential Weisswasser at
Madelstegbaude, at an altitude of 2230 ft., and thereafter the united
stream of the Elbe pursues a southerly course, emerging from the
mountain glens at Hohenelbe (1495 ft.), and continuing on at a soberer
pace to Pardubitz, where it turns sharply to the west, and at Kolin (730
ft.), some 27 m. farther on, bends gradually towards the north-west. A
little above Brandeis it picks up the Iser, which, like itself, comes
down from the Riesengebirge, and at Melnik it has its stream more than
doubled in volume by the Moldau, a river which winds northwards through
the heart of Bohemia in a sinuous, trough-like channel carved through
the plateaux. Some miles lower down, at Leitmeritz (433 ft.), the waters
of the Elbe are tinted by the reddish Eger, a stream which drains the
southern slopes of the Erzgebirge. Thus augmented, and swollen into a
stream 140 yds. wide, the Elbe carves a path through the basaltic mass
of the Mittelgebirge, churning its way through a deep, narrow rocky
gorge. Then the river winds through the fantastically sculptured
sandstone mountains of the "Saxon Switzerland," washing successively the
feet of the lofty Lilienstein (932 ft. above the Elbe), the scene of one
of Frederick the Great's military exploits in the Seven Years' War,
Konigstein (797 ft. above the Elbe), where in times of war Saxony has
more than once stored her national purse for security, and the pinnacled
rocky wall of the Bastei, towering 650 ft. above the surface of the
stream. Shortly after crossing the Bohemian-Saxon frontier, and whilst
still struggling through the sandstone defiles, the stream assumes a
north-westerly direction, which on the whole it preserves right away to
the North Sea. At Pirna the Elbe leaves behind it the stress and turmoil
of the Saxon Switzerland, rolls through Dresden, with its noble river
terraces, and finally, beyond Meissen, enters on its long journey across
the North German plain, touching Torgau, Wittenberg, Magdeburg,
Wittenberge, Hamburg, Harburg and Altona on the way, and gathering into
itself the waters of the Mulde and Saale from the left, and those of the
Schwarze Elster, Havel and Elde from the right. Eight miles above
Hamburg the stream divides into the Norder (or Hamburg) Elbe and the
Suder (or Harburg) Elbe, which are linked together by several
cross-channels, and embrace in their arms the large island of
Wilhelmsburg and some smaller ones. But by the time the river reaches
Blankenese, 7 m. below Hamburg, all these anastomosing branches have
been reunited, and the Elbe, with a width of 4 to 9 m. between bank and
bank, travels on between the green marshes of Holstein and Hanover until
it becomes merged in the North Sea off Cuxhaven. At Kolin the width is
about 100 ft., at the mouth of the Moldau about 300, at Dresden 960, and
at Magdeburg over 1000. From Dresden to the sea the river has a total
fall of only 280 ft., although the distance is about 430 m. For the 75
m. between Hamburg and the sea the fall is only 3-1/4 ft. One consequence
of this is that the bed of the river just below Hamburg is obstructed by
a bar, and still lower down is choked with sandbanks, so that navigation
is confined to a relatively narrow channel down the middle of the
stream. But unremitting efforts have been made to maintain a sufficient
fairway up to Hamburg (q.v.). The tide advances as far as Geesthacht, a
little more than 100 m. from the sea. The river is navigable as far as
Melnik, that is, the confluence of the Moldau, a distance of 525 m., of
which 67 are in Bohemia. Its total length is 725 m., of which 190 are in
Bohemia, 77 in the kingdom of Saxony, and 350 in Prussia, the remaining
108 being in Hamburg and other states of Germany. The area of the
drainage basin is estimated at 56,000 sq. m.
_Navigation._--Since 1842, but more especially since 1871, improvements
have been made in the navigability of the Elbe by all the states which
border upon its banks. As a result of these labours there is now in the
Bohemian portion of the river a minimum depth of 2 ft. 8 in., whilst
from the Bohemian frontier down to Magdeburg the minimum depth is 3 ft.,
and from Magdeburg to Hamburg, 3 ft. 10 in. In 1896 and 1897 Prussia and
Hamburg signed covenants whereby two channels are to be kept open to a
depth of 9-3/4 ft., a width of 656 ft., and a length of 550 yds. between
Bunthaus and Ortkathen, just above the bifurcation of the Norder Elbe
and the Suder Elbe. In 1869 the maximum burden of the vessels which were
able to ply on the upper Elbe was 250 tons; but in 1899 it was increased
to 800 tons. The large towns through which the river flows have vied
with one another in building harbours, providing shipping accommodation,
and furnishing other facilities for the efficient navigation of the
Elbe. In this respect the greatest efforts have naturally been made by
Hamburg; but Magdeburg, Dresden, Meissen, Riesa, Tetschen, Aussig and
other places have all done their relative shares, Magdeburg, for
instance, providing a commercial harbour and a winter harbour. In spite,
however, of all that has been done, the Elbe remains subject to serious
inundations at periodic intervals. Among the worst floods were those of
the years 1774, 1799, 1815, 1830, 1845, 1862, 1890 and 1909. The growth
of traffic up and down the Elbe has of late years become very
considerable. A towing chain, laid in the bed of the river, extends from
Hamburg to Aussig, and by this means, as by paddle-tug haulage, large
barges are brought from the port of Hamburg into the heart of Bohemia.
The fleet of steamers and barges navigating the Elbe is in point of fact
greater than on any other German river. In addition to goods thus
conveyed, enormous quantities of timber are floated down the Elbe; the
weight of the rafts passing the station of Schandau on the Saxon
Bohemian frontier amounting in 1901 to 333,000 tons.
A vast amount of traffic is directed to Berlin, by means of the
Havel-Spree system of canals, to the Thuringian states and the Prussian
province of Saxony, to the kingdom of Saxony and Bohemia, and to the
various riverine states and provinces of the lower and middle Elbe. The
passenger traffic, which is in the hands of the Sachsisch-Bohmische
Dampfschifffahrtsgesellschaft is limited to Bohemia and Saxony, steamers
plying up and down the stream from Dresden to Melnik, occasionally
continuing the journey up the Moldau to Prague, and down the river as
far as Riesa, near the northern frontier of Saxony, and on the average
1-1/2 million passengers are conveyed.
In 1877-1879, and again in 1888-1895, some 100 m. of canal were dug, 5
to 6-1/2 ft. deep and of various widths, for the purpose of connecting
the Elbe, through the Havel and the Spree, with the system of the Oder.
The most noteworthy of these connexions are the Elbe Canal (14-1/4 m.
long), the Reek Canal (9-1/2 m.), the Rudersdorfer Gewasser (11-1/2 m.),
the Rheinsberger Canal (11-1/4 m.), and the Sacrow-Paretzer Canal (10
m.), besides which the Spree has been canalized for a distance of 28 m.,
and the Elbe for a distance of 70 m. Since 1896 great improvements have
been made in the Moldau and the Bohemian Elbe, with the view of
facilitating communication between Prague and the middle of Bohemia
generally on the one hand, and the middle and lower reaches of the Elbe
on the other. In the year named a special commission was appointed for
the regulation of the Moldau and Elbe between Prague and Aussig, at a
cost estimated at about L1,000,000, of which sum two-thirds were to be
borne by the Austrian empire and one-third by the kingdom of Bohemia.
The regulation is effected by locks and movable dams, the latter so
designed that in times of flood or frost they can be dropped flat on the
bottom of the river. In 1901 the Austrian government laid before the
Reichsrat a canal bill, with proposals for works estimated to take
twenty years to complete, and including the construction of a canal
between the Oder, starting at Prerau, and the upper Elbe at Pardubitz,
and for the canalization of the Elbe from Pardubitz to Melnik (see
AUSTRIA: _Waterways_). In 1900 Lubeck was put into direct communication
with the Elbe at Lauenburg by the opening of the Elbe-Trave Canal, 42 m.
in length, and constructed at a cost of L1,177,700, of which the state
of Lubeck contributed L802,700, and the kingdom of Prussia L375,000. The
canal has been made 72 ft. wide at the bottom, 105 to 126 ft. wide at
the top, has a minimum depth of 8-1/6 ft., and is equipped with seven
locks, each 262-1/2 ft. long and 39-1/4 ft. wide. It is thus able to
accommodate vessels up to 800 tons burden; and the passage from Lubeck
to Lauenburg occupies 18 to 21 hours. In the first year of its being
open (June 1900 to June 1901) a total of 115,000 tons passed through the
canal.[1] A gigantic project has also been put forward for providing
water communication between the Rhine and the Elbe, and so with the
Oder, through the heart of Germany. This scheme is known as the Midland
Canal. Another canal has been projected for connecting Kiel with the
Elbe by means of a canal trained through the Plon Lakes.
_Bridges._--The Elbe is crossed by numerous bridges, as at Koniggratz,
Pardubitz, Kolin, Leitmeritz, Tetschen, Schandau, Pirna, Dresden,
Meissen, Torgau, Wittenberg, Rosslau, Barby, Magdeburg, Rathenow,
Wittenberge, Domitz, Lauenburg, and Hamburg and Harburg. At all these
places there are railway bridges, and nearly all, but more especially
those in Bohemia, Saxony and the middle course of the river--these last
on the main lines between Berlin and the west and south-west of the
empire--possess a greater or less strategic value. At Leitmeritz there
is an iron trellis bridge, 600 yds long. Dresden has four bridges, and
there is a fifth bridge at Loschwitz, about 3 m. above the city. Meissen
has a railway bridge, in addition to an old road bridge. Magdeburg is
one of the most important railway centres in northern Germany; and the
Elbe, besides being bridged--it divides there into three arms--several
times for vehicular traffic, is also spanned by two fine railway
bridges. At both Hamburg and Harburg, again, there are handsome railway
bridges, the one (1868-1873 and 1894) crossing the northern Elbe, and
the other (1900) the southern Elbe; and the former arm is also crossed
by a fine triple-arched bridge (1888) for vehicular traffic.
_Fish._--The river is well stocked with fish, both salt-water and
fresh-water species being found in its waters, and several varieties of
fresh-water fish in its tributaries. The kinds of greatest economic
value are sturgeon, shad, salmon, lampreys, eels, pike and whiting.
_Tolls._--In the days of the old German empire no fewer than thirty-five
different tolls were levied between Melnik and Hamburg, to say nothing
of the special dues and privileged exactions of various riparian owners
and political authorities. After these had been _de facto_, though not
_de jure_, in abeyance during the period of the Napoleonic wars, a
commission of the various Elbe states met and drew up a scheme for their
regulation, and the scheme, embodied in the Elbe Navigation Acts, came
into force in 1822. By this a definite number of tolls, at fixed rates,
was substituted for the often arbitrary tolls which had been exacted
previously. Still further relief was afforded in 1844 and in 1850, on
the latter occasion by the abolition of all tolls between Melnik and the
Saxon frontier. But the number of tolls was only reduced to one, levied
at Wittenberge, in 1863, about one year after Hanover was induced to
give up the Stade or Brunsbuttel toll in return for a compensation of
2,857,340 thalers. Finally, in 1870, 1,000,000 thalers were paid to
Mecklenburg and 85,000 thalers to Anhalt, which thereupon abandoned all
claims to levy tolls upon the Elbe shipping, and thus navigation on the
river became at last entirely free.
_History._--The Elbe cannot rival the Rhine in the picturesqueness of
the scenery it travels through, nor in the glamour which its romantic
and legendary associations exercise over the imagination. But it
possesses much to charm the eye in the deep glens of the Riesengebirge,
amid which its sources spring, and in the bizarre rock-carving of the
Saxon Switzerland. It has been indirectly or directly associated with
many stirring events in the history of the German peoples. In its lower
course, whatever is worthy of record clusters round the historical
vicissitudes of Hamburg--its early prominence as a missionary centre
(Ansgar) and as a bulwark against Slav and marauding Northman, its
commercial prosperity as a leading member of the Hanseatic League, and
its sufferings during the Napoleonic wars, especially at the hands of
the ruthless Davout. The bridge over the river at Dessau recalls the hot
assaults of the _condottiere_ Ernst von Mansfeld in April 1626, and his
repulse by the crafty generalship of Wallenstein. But three years later
this imperious leader was checked by the heroic resistance of the
"Maiden" fortress of Magdeburg; though two years later still she lost
her reputation, and suffered unspeakable horrors at the hands of Tilly's
lawless and unlicensed soldiery. Muhlberg, just outside the Saxon
frontier, is the place where Charles V. asserted his imperial authority
over the Protestant elector of Saxony, John Frederick, the Magnanimous
or Unfortunate, in 1547. Dresden, Aussig and Leitmeritz are all
reminiscent of the fierce battles of the Hussite wars, and the last
named of the Thirty Years' War. But the chief historical associations of
the upper (i.e. the Saxon and Bohemian) Elbe are those which belong to
the Seven Years' War, and the struggle of the great Frederick of Prussia
against the power of Austria and her allies. At Pirna (and Lilienstein)
in 1756 he caught the entire Saxon army in his fowler's net, after
driving back at Lobositz the Austrian forces which were hastening to
their assistance; but only nine months later he lost his reputation for
"invincibility" by his crushing defeat at Kolin, where the great highway
from Vienna to Dresden crosses the Elbe. Not many miles distant, higher
up the stream, another decisive battle was fought between the same
national antagonists, but with a contrary result, on the memorable 3rd
of July 1866.
See M. Buchheister, "Die Elbe u. der Hafen von Hamburg," in _Mitteil.
d. Geog. Gesellsch. in Hamburg_ (1899), vol. xv. pp. 131-188; V. Kurs,
"Die kunstlichen Wasserstrassen des deutschen Reichs," in _Geog.
Zeitschrift_ (1898), pp. 601-617; and (the official) _Der Elbstrom_
(1900); B. Weissenborn, _Die Elbzolle und Elbstapelplatze im
Mittelalter_ (Halle, 1900); Daniel, _Deutschland_; and A. Supan,
_Wasserstrassen und Binnenschifffahrt_ (Berlin, 1902).