Aldborough formerly returned two members to parliament, but
was disfranchised by the Reform Act of 1832. The place is
remarkable from its numerous ancient remains. It was the
Isurium Brigantum of the Romans, originally perhaps a capital
of the Brigantes tribe, and afterwards a Romano-British town
of considerable size. Inscriptions, beautiful mosaics and
other traces of comfortable houses have been found, with
many potsherds, coins and bronze, iron and other objects;
and a large part of the town walls, several mosaics and
parts of buildings, can be seen. A fine collection is kept
in the Museum Isurianum in the grounds of the manor-house.
ALDEBURGH [ALDBOROUGH], a market town and municipal
borough in the Eye parliamentary division of Suffolk, England,
the terminus of a branch of the Great Eastern railway, 99 1/2
m. N.E. by E. from London. Area, 1629 acres. Pop. (1901)
2405. The surrounding district is open and somewhat bleak,
but a fine stretch of sand fringes the shallow inlet of
the North Sea known as Aldeburgh Bay. To the W. the river
Alde broadens as if into an estuary, but its outflow is
here prevented by the sand, and it runs south for nearly
10 m. parallel with the shore. The sandbanks have arrested
the encroachments of the sea, which submerged a former
site of Aldeburgh. The church of St Peter and St Paul is
Perpendicular, largely restored, and contains a monument to
the poet George Crabbe, born here on the 24th of December
1754. A small picturesque Moot Hall of the 16th century is
used for corporation meetings. Slaughden Quay on the Alde
admits small vessels, and fishing is carried on. Aldeburgh
is governed by a mayor, 4 aldermen and 12 councillors.
Aldeburgh (Aldburc) takes its name from the river Alde
on which it stands. It is not mentioned in pre-Conquest
records, but at the Domesday survey most of the land was held
by Robert Malet, a Norman. In 1155 the manor was granted
to the abbey of St John of Colchester, later to Cardinal
Wolsey, and on his disgrace, to Thomas Howard, duke of Norfolk,
to whom Elizabeth in 1567 granted a market on Saturday.
In the 16th century Aldeburgh was a place of considerable
commercial importance, due, no doubt, to its position on the
sea-coast. Aldeburgh claims to be a borough by prescription:
the earliest charter is that granted by Henry VIII. in
1529. Edward VI. in 1548 raised it to the rank of a free
borough, granting a charter of incorporation and a market on
Wednesday. Later charters were granted by Philip and Mary in
1553, by Elizabeth in 1558 and 1567, by James I. (who granted
two annual fairs) in 1606, and by Charles I. in 1631 and
1637. The corporation included 2 bailiffs, 10 capital and
24 inferior burgesses, until the Municipal Corporations Act
1883. The fairs and markets became so unimportant that
they were discontinued about the middle of the 19th
century. The town returned two members to Elizabeth's
parliament of 1572, and continued to be so represented
till the Reform Bill of 1832 disfranchised it. Frequent
disastrous incursions of the sea in the 18th century reduced
Aldeburgh to a mere fishing village. In recent years it
has grown as a seaside resort, with excellent golf-links.
See John Kirby, The Suffolk Traveller (2nd ed., 1764); N. F. Hele,
Notes about Aldeburgh (1870); Victoria County History--Suffolk.
ALDEGREVER, or ALDEGRAF, HEINRICH (1502-1558), German
painter and engraver, was born at Paderborn, from which he
removed in early life to Soest, where he died. From the close
resemblance of his style to that of Albrecht Durer he has
sometimes been called the Albert of Westphalia. His numerous
engravings, chiefly from his own designs, are delicate and
minute, though somewhat hard in style, and entitle him to a
place in the front rank of the so-called ``Little Masters.''
There is a good collection in the British Museum. Specimens
of his painting are exceedingly rare. Five pictures are
in continental galleries, but the genuineness of the works
in the Vienna and Munich collections attributed to him is
at least doubtful, the only unchallenged example being a
portrait of Engelbert Therlaen (1551) in the Berlin Museum.
ALDEHYDES, a class of chemical compounds of the general
formula R.CHO (R = an alkyl or an aryl group). The name is
derived from alcohol dehydrogenatum in allusion to the fact
that they may be prepared by the oxidation of alcohols. The
lower members of the series are neutral liquids possessing
a characteristic smell; they are soluble in water and are
readily volatile (formaldehyde, however, is a gas at ordinary
temperatures). As the carbon content of the molecule
increases, they become less soluble in water, and their smell
becomes less marked with the increase in boiling point, the
highest members of the series being odourless solids, which
can only be distilled without decomposition in vacuo.
The aldehydes may be prepared by the careful oxidation of
primary alcohols with a mixture of potassium dichromate and
sulphuric acid,--3R.CH2OH + K2 Cr2O7 + 4H2SO4 = K2SO4
+ Cr2(SO4)3 + 7H2O + 3R.CHO; by distilling the calcium
salts of the fatty acids with calcium formate; and by hydrolysis
of the acetals. L. Bouveault (Bull. soc. chim., 1904 [3],
31, p. 1306) prepares aldehydes by the gradual addition of
disubstituted formamides (dissolved in anhydrous ether) to
magnesium alkyl haloids, the best yields being obtained by
the use of diethyl formamide. Secondary reactions take place
at the same time, yielding more particularly hydrocarbons
of the paraffin series. G. Darzens (Comptes Rendus, 1904,
139, p. 1214) prepares esters of disubstituted glycidic acids,
by condensing the corresponding ketone with monochloracetic
ester, in the presence of sodium ethylate. These esters on
hydrolysis yield the free acids, which readily decompose,
with loss of carbon dioxide and formation of an aldehyde,
/R /CRR1 /CRR1
OC< + Cl.CH2.COOC2H5 --> O< | --> O< |
\R1 \CH.COOC2H5 \CH.COOH
--> CO2 + CHRR1.CHO.
In the German Patent 157573 (1904) it is shown that by
the action of at least two molecular proportions of an alkyl
formate on two molecular proportions of a magnesium alkyl
or aryl haloid, a complex addition compound is formed, which
readily decomposes into a basic magnesium salt and an aldehyde,
C6H5MgBr + HCOOR --> RO.CH.C6H5.OMgBr --> MgBr.OR + C6H5CHO.
The aldehydes are characterized by their great chemical
reactivity. They act as reducing agents, silver nitrate
in the presence of ammonia being rapidly reduced to the
condition of metallic silver. They are easily oxidized to the
corresponding fatty acid, in many cases simply by exposure to
air. Nascent hydrogen reduces them to primary alcohols,
and phosphorus pentachloride replaces the carbonyl oxygen by
chlorine. They form many addition compounds, combining with
ammonia to form aldehyde ammonias of the type R.CH(OH).NH2.
These are colourless crystalline compounds, which are most readily
prepared by passing ammonia gas into an ethereal solution of the
aldehyde. With sodium bisulphite they form the so-called
bisulphite compounds R.CH(OH).SO3Na, which are readily resolved
into their components by distillation with dilute acids, and
are frequently used for the preparation of the pure aldehyde.
With hydrocyanic acid aldehydes form the cyanhydrins R.CH(OH).CN.
They react with hydroxylamine and phenylhydrazine, with the
formation of aldoximes and hydrazones. (For the isomerism of
the aldoximes see OXIMES.) The hydrazones are crystalline
substances which are of value in the characterization of the
aldehydes. Both oximes and hydrazones, on boiling with dilute
acid, regenerate the parent aldehyde. The hydrazones are
best prepared by mixing the aldehyde with phenylhydrazine
in dilute acetic acid solution, in the absence of any free
mineral acid. Semioxamazid, NH2.CO.CO.NH.NH2, has
also been employed for the identification of aldehydes
(W. Kerp and K. Unger, Berichte, 1897, 30. p. 585).
Aldehydes are converted into resins by the action of caustic
alkalies. On heating with alcohols to 100 deg. C. they form
acetals, and they also form condensation products with
para-amido-di-methyl-aniline (A. Calm, Berichte, 1884, 17, p.
2939). They react with the zinc alkyls to form addition products,
which are decomposed by water with formation of secondary
alcohols (K. Thurnlach, Annalen, 1882, 213, p. 369) thus:--
Zn(C2H5)2 H2O
/C2H5 /C2H5
CH3.CHO --> CH3.CH< --> CH3.CH< + ZnO + C2H6.
\OZnC2H5 \OH
The reaction is a general one for all aldehydes with zinc methyl
and zinc ethyl, but not with the higher zinc alkyls. V. Grignard
(Comptes Rendus, 1900 et seq.) showed that aldehydes combine
with magnesium alkyl iodides (in absolute ether solution) to
form addition products, which are decomposed by water with
the formation of secondary alcohols, thus from acetaldehyde
and magnesium methyl iodide, isopropyl alcohol is obtained.
H2O
/CH3
CH3.CHO + CH3MgI --> CH3.CH< --> (CH3)2CH.OH + MgI.OH.
\OMgI
The lower members of the aliphatic series are characterized
by their power of polymerization (see FORMALIN, and the
account of Acetaldehyde below), and also by the so-called
``aldol'' condensation, acetaldehyde in this way forming
aldol, CH3.CHOH.CH2.CHO. These aldols generally lose
the elements of water readily and pass into unsaturated
compounds; aldol itself on distillation at ordinary
atmospheric pressure gives crotonaldehyde, CH3.CH:CH.CHO.
Aldehydes are characterized by the reddish-violet colour which
they give with a solution of fuchsine that has been decolorized
by sulphurous acid (H. Schiff, Ann., 1866, 140, p. 131).
With diazobenzene sulphonic acid in the presence of alkali
and a trace of sodium amalgam, a reddish-violet coloration
is formed on standing (E. Fischer, Ber., 1883, 16, p.
657). A. Angeli (Gazz. chim. Ital., 1896, 22, ii. 17) has
shown that aldehydes in the presence of nitrohydroxylaminic
acid form hydroxamic acid. The aldehydes condense readily
with acetoacetic ester in the presence of ammonia, to pyridines
(see PYRIDINE), whilst O. Doebner and W. v. Miller (Ber.,
1892, 25, p. 2864; 1896, 29, p. 59) have shown that in the
presence of aniline and sulphuric acid they give substituted
quinolines. (See also C. Beyer, Ber., 1887, 20, p. 1908).
The chief aldehydes are shown in the following table:--
_____________________________________________________________________________
| Name. | Formula | Boiling | Melting|
| | | Point. | Point.|
|--------------------|-----------------------------------|---------|--------|
| Formaldehyde | H.CHO |-21 deg. | |
| Acetaldehyde | CH3.CHO | 20.8 deg. | |
| Propyl aldehyde | CH3.CH2.CHO | 49 deg. | |
| n-Butyl '' | CH3.(CH2)2.CHO | 75 deg. | |
| iso- '' '' | (CH3)2.CH.CHO | 61 deg. | |
| n-Valeryl '' | CH3.(CH2)3.CHO |103 deg. | |
| iso- '' '' | (C4H9.CHO | 92 deg. | |
