AMPERE, JEAN JACQUES (1800-1864), French philologist and

man of letters, only son of Andre Marie Ampere, was born at

Lyons on the 12th of August 1800. He studied the folk-songs

and popular poetry of the Scandinavian countries in an extended

tour in northern Europe. Returning to France, he delivered

in 1830 a series of lectures on Scandinavian and early German

poetry at the Athenaeum in Marseilles. The first of these

was printed as De l'Histoire de la poesie (1830), and was

practically the first introduction of the French public to

the Scandinavian and German epics. In Paris he taught at

the Sorbonne, and became professor of the history of French

literature at the College de France. A journey in northern

Africa (1841) was followed by a tour in Greece and Italy, in

company with Prosper Merimee and others. This bore fruit

in his Voyage dantesque (printed in his Grece, Rome et

Dante, 1848), which did much to popularize the study of Dante in

France. In 1848 he became a member of the French Academy, and

in 1851 he visited America. From this time he was occupied

with his chief work, L'Histoire romaine a Rome (4 vols.,

1861-1864), until his death at Pau on the 27th of March 1864.

The Correspondance et souvenirs (2 vols.) of A. M. and J. J.

Ampere (1805-1854) was published in 1875. Notices of J. J. Ampere

are to be found in Sainte-Beuve's Portraits litteraires, vol.

iv., and Nouveaux Lundis, vol. xiii.; and in P. Merimee's

Portraits historiques et litteraires (2nd ed., 1875).

AMPEREMETER, or AMMETER, an instrument for the measurement

of electric currents in terms of the unit called the ampere.

(See ELECTROKINETICS; CONDUCTION, ELECTRIC; and UNITS,

PHYSICAL.) Since electric currents may be either continuous,

i.e. unidirectional, or alternating, and the latter of high or

of low frequency, amperemeters may first be divided into those

(1) for continuous or direct currents, (2) for low frequency

alternating currents, and (3) for high frequency alternating

currents. A continuous electric current of one ampere is

defined to be one which deposits electrolytically 0.001118 of

a gramme of silver per second from a neutral solution of silver

nitrate.1 An alternating current of one ampere is defined

to be one which produces the same heat in a second in a wire

as the unit continuous current defined as above to be one

ampere. These definitions provide a basis on which the

calibration of amperemeters can be conducted. Amperemeters

may then be classified according to the physical principle

on which they are constructed. An electric current in a

conductor is recognized by its ability (a) to create heat

in a wire through which it passes, (b) to produce a magnetic

field round the conductor or wire. The heat makes itself

evident by raising the temperature and therefore elongating

the wire, whilst the magnetic field creates mechanical forces

which act on pieces of iron or other conductors conveying

electric currents when placed in proximity to the conductor in

question. Hence we may classify ammeters into (1) Thermal;

(2) Electromagnetic, and (3) Electrodynamic instruments.

1. Thermal Ammeters.--These instruments are also called

hot-wire ammeters. In their simplest form they consist

of a wire through which passes the current to be measured,

some arrangement being provided for measuring the small

expansion produced by the heat generated in the wire.

This may consist simply in attaching one end of the wire

to an index lever and the other to a fixed support, or the

elongation of the wire may cause a rotation in a mirror from

which a ray of light is reflected, and the movement of this

ray over a scale will then provide, the necessary means of

indication. It is found most convenient to make use of the

sag of the wire produced when it is stretched between two

fixed points (K1K2, fig. 1) and then heated. To render

the elongation evident, another wire is attached to its

centre S2, this last having a thread fixed to its middle of

which the other end is twisted round the shaft of an index

needle or in some way connected to it through a multiplying

gear. The expansion of the working wire when it is heated will

then increase or create a sag in it owing to its increase in

FIG. 1.--Diagram showing the arrangements

of Hartmann and Braun's Hotwire Ammeter.

length, and this is multiplied and rendered evident by the

movement of the index needle. In order that this may take

place, the heated wire must be flexible and must therefore

be a single fine wire or a bundle of fine wires. In ammeters

for small currents it is customary to pass the whole current

through the heating wire. In instruments for larger currents

the main current passes through a metallic strip acting

as a bye-pass or shunt, and to the ends of this shunt are

attached the ends of the working wire. A known fraction

of the current is then indicated and measured. This shunt

is generally a strip of platinoid or constantin, and the

working wire itself is of the same metal. There is therefore

a certain ratio in which any current passing through the

ammeter is divided between the shunt and the working wire.

Thermal ammeters recommend themselves for the following

reasons:--(1) the same instrument can be used for continuous

currents and for alternating currents of low frequency;

(2) there is no temperature correction, (3) if used with

alternating currents no correction is necessary for frequency,

unless that frequency is very high. It is, however, requisite

to make provision for the effect of changes in atmospheric

temperature. This is done by mounting the working wire on

a metal plate made of the same metal as the working wire

itself; thus if the working wire is of platinoid it must

be mounted on a platinoid bar, the supports which carry

the ends of the working wire being insulated from this bar

by being bushed with ivory or porcelain. Then no changes

of external temperature can affect the sag of the wire,

and the only thing which can alter its length relatively

to the supporting bar is the passage of a current through

it. Hot-wire ammeters are, however, liable to a shift of

zero, and means are always provided by some adjusting screw

for slightly altering the sag of the wire and so adjusting

the index needle to the zero of the scale. Hot-wire ammeters

are open to the following objections:--The scale divisions

for equal increments of current are not equal in length,

being generally much closer together in the lower parts of the

scale. The reason is that the heat produced in a given

time in a wire is proportional to the square of the strength

of the current passing through it, and hence the rate at

which the heat is produced in the wire, and therefore its

temperature, increases much faster than the current itself

increases. From this it follows that hot-wire ammeters are

generally not capable of giving visible indications below a

certain minimum current for each instrument. The instrument

therefore does not begin to read from zero current, but from

some higher limit which, generally speaking, is about one-tenth

of the maximum, so that an ammeter reading up to 10 amperes

will not give much visible indication below 1 ampere. On

the other hand, hot-wire instruments are very ``dead-beat,''

that is to say, the needle does not move much for the small

fluctuations in the current, and this quality is generally

increased by affixing to the index needle a small copper plate

which is made to move in a strong magnetic field (see fig.

2). Hot-wire instruments working on the sag principle can be

used in any position if properly constructed, and are very

portable. In the construction of such an instrument it is

essential that the wire should be subjected to a process of

preparation or ``ageing,'' which consists in passing through

it a fairly strong current, at least the maximum that it will

ever have to carry, and starting and stopping this current

frequently. The wire ought to be so treated for many hours

FIG. 2.--Hot-wire Ammeter.

before it is placed in the instrument. It is also necessary

to notice that shunt instruments cannot be used for high

frequencies, as then the relative inductance of the shunt and wire

becomes important and affects the ratio in which the current is

divided, whereas for low frequency currents the inductance is

unimportant. In constructing a hot-wire instrument for the

measurement of high frequency currents it is necessary to

make the working wire of a number of fine wires placed in

parallel and slightly separated from one another, and to-pass

the whole of the current to be measured through this strand.

In certain forms, hot-wire instruments are well adapted for

the measurement of very small alternating currents. One useful

form has been made as follows:--Two fine wires of diameter

not greater than .001 in. are stretched parallel to one

another and 2 or 3 mm. apart. At the middle of these parallel

wires, which are preferably about 1 m. in length, rests a

very light metallic bridge to which a mirror is attached,

the mirror reflecting a ray of light from a lamp upon a

screen. If a small alternating current is passed through one

wire, it sags down, the mirror is tilted, and the spot of

light on the screen is displaced. Changes of atmospheric

temperature affect both wires equally and do not tilt the

mirror. The instrument can be calibrated by a continuous

current. Another form of hot-wire ammeter is a modification

of the electric thermometer originally invented by Sir W. Snow

Harris. It consists of a glass bulb, in which there is a loop

of fine wire, and to the bulb is attached a U-tube in which

there is some liquid. When a current is passed through the

wire, continuous or alternating, it creates heat, which expands

the air in the bulb and forces the liquid up one side of the

U-tube to a certain position in which the rate of loss of

heat by the air is equal to the rate at which it is gaining

heat. The instrument can be calibrated by continuous currents

and may then be used for high frequency alternating currents.

2. Electromagnetic Ammeters.--Another large class of ammeters

depend for their action upon the fact that an electric current

creates an electric field round its conductor, which varies in

strength from point to point, but is otherwise proportional to the

current. A small piece of iron placed in this field tends to move

from weak to strong places in the field with a force depending

on the strength of the field and the rate at which the field

varies. In its simplest form an electromagnetic ammeter consists

of a circular coil of wire in which is pivoted eccentrically

an index needle carrying at its lower end a small mass of

iron. The needle is balanced so that gravity compels it to

take a certain position in which the fragment of iron occupies

a position in the centre of the field of the coil where it is

weakest. When a current is passed through the coil the

iron tends to move nearer to the coil of the wire where the

field is stronger and so displaces the index needle over the

scale. Such an instrument is called a soft-iron gravity

ammeter. Another type of similar instrument consists of a coil

of wire having a fragment of iron wire suspended from one arm

of an index needle near the mouth of a coil. When a current

is passed through the wire forming the coil, the fragment of

iron is drawn more into the aperture of the coil where the

field is stronger and so displaces an index needle over a

scale. In the construction of this soft-iron instrument it

is essential that the fragment of iron should be as small and

as well annealed as possible and not touched with tools after

annealing; also it should be preferably not too elongated in shape

so that it may not acquire permanent magnetization but that its

magnetic condition may follow the changes of the current in the

coil. If these conditions are not fulfilled sufficiently,

the ammeter will not give the same indications for the same

current if that current has been reached (a) by increasing

from a smaller current, or (b) by decreasing from a larger

current. In this case there is said to be hysteresis in the

readings. Although therefore most simple and cheap to construct,

such soft-iron instruments are not well adapted for accurate

work. A much better form of electromagnetic ammeter can be

constructed on a principle now extensively employed, which

consists in pivoting in the strong field of a permanent magnet a

small coil through which a part of the current to be measured is

sent. Such an instrument is called a shunted movable coil ammeter,

and is represented by a type of instrument shown in fig. 3. The

FIG. 3.--Shunted Movable Coil Ammeter, Isenthal & Co.

construction of this instrument is as follows:--Within

the instrument is a horseshoe magnet having soft-iron

pole pieces so arranged as to produce a uniform magnetic

field. In this magnetic field is pivoted a small circular

or rectangular coil carried in jewelled bearings, the current

being passed into and out of the movable coil by fine flexible

conductors. The coil carries an index needle moving over a

scale, and there is generally an iron core in the interior

of the coil but fixed and independent of it. The coil is

so situated that, in its zero position when no current is

passing through it, the plane of the coil is parallel to

the direction of the lines of force of the field. When a

current is passed through the coil it rotates in the field

and displaces the index over the scale against the control

of a spiral spring like the hairspring of a watch. Such

instruments can be made to have equidivisional scales and to

read from zero upwards. It is essential that the permanent

magnet should be subjected to a process of ageing so that

its field may not be liable to change subsequently with time.

In the case of ammeters intended for very small currents, the

whole current can be sent through the coil, but for larger

currents it is necessary to provide in the instrument a

shunt which carries the main current, the movable coil being

connected to the ends of this shunt so that it takes a definite

small fraction of the current passed through the instrument.

Instruments of this type with a permanent magnetic field are

only available for the measurement of continuous currents, but

soft-iron instruments of the above-described gravity type can

be employed with certain restrictions for the measurement of

alternating currents. Direct reading equidivisional movable

coil ammeters can be made in various portable forms, and

are very much employed as laboratory instruments and also as

ammeters for the measurement of large electric currents in

electric generating stations. In this last case the shunt

need not be contained in the instrument itself but may be at

a considerable distance, wires being brought from the shunt

which carries the main current to the movable coil ammeter

itself, which performs the function simply of an indicator,

3. Electrodynamic Ammeters.--Instruments of the third class

depend for their action on the fact discovered by Ampere,

that mechanical forces exist between conductors carrying

electric currents when those conductors occupy certain relative

positions. If there be two parallel wires through which

currents are passing, then these wires are drawn together

if the currents are in the same direction and pressed apart

if they are in opposite directions. (See ELECTROKINETICS.)

Instruments of this type are called Electrodynamometers, and

have been employed both as laboratory research instruments

and for technical purposes. In one well-known form, called

a Siemens Electrodynamometer, there is a fixed coil (fig.

4), which is surrounded by another coil having its axis at

right angles to that of the fixed coil. This second coil is

suspended by a number of silk fibres, and to the coil is also

attached a spiral spring the other end of which is fastened

to a torsion head. If then the torsion head is twisted, the

suspended coil experiences a torque and is displaced through

FIG. 4.--Siemens Electrodynamometer. F, Fixed

coil; D, Movable coil; S, Spiral spring; T,

Torsion head; MM, Mercury cups; I, Index needle.

an angle equal to that of the torsion head. The current can

be passed into and out of the movable coil by permitting the

ends of the coil to dip into two mercury cups. If a current

is passed through the fixed coil and movable coil in series

with one another, the movable coil tends to displace itself so

as to bring the axes of the coils, which are normally at right

angles, more into the same direction. This tendency can be

resisted by giving a twist to the torsion head and so applying

to the movable coil through the spring a restoring torque,

which opposes the torque due to the dynamic action of the

currents. If then the torsion head is provided with an index

needle, and also if the movable coil is provided with an

indicating point, it is possible to measure the torsional angle

through which the head must be twisted to bring the movable

coil back to its zero position. In these circumstances the

torsional angle becomes a measure of the torque and therefore

of the product of the strengths of the currents in the two

coils, that is to say, of the square of the strength of the

current passing through the two coils if they are joined up in

series. The instrument can therefore be graduated by passing

through it known and measured continuous currents, and it then

becomes available for use with either continuous or alternating

currents. The instrument can be provided with a curve or table

showing the current corresponding to each angular displacement

of the torsion head. It has the disadvantage of not being

direct reading when made in the usual form, but can easily be

converted into a direct reading instrument by appropriately

dividing the scale over which the index of the torsion head moves.

Ampere Balance.--Very convenient and accurate instruments based

on the above principles have been devised by Lord Kelvin, and

a large variety of these ampere balances, as they are called,

suitable for measuring currents from a fraction of an ampere

up to many thousands of amperes, have been constructed by that

illustrious inventor. The difficulty which has generally presented

itself to those who have tried to design instruments on the

FIG. 5.--Kelvin Flexible Metallic Ligament.

electrodynometer principle for use with large currents has

been that of getting the current into and out of the movable

conductor, and yet permitting that conductor to remain free to

move under very small force. The use of mercury cups is open to

many objections on account of the fact that the mercury becomes

oxidized, and such instruments are not very convenient for

transportation. The great novelty in the ampere balances

of Lord Kelvin was a joint or electric coupling, which is at

once exceedingly flexible and yet capable of being constructed

to carry with safety any desired current. This he achieved

by the introduction of a device which is called a metallic

ligament. The general principle of its construction is as

follows:--Let +A, -A (fig. 5), be a pair of semi-cylindrical

fixed trunnions which are carried on a supporting frame and

held with flat sides downwards. Let +B, -B, be two smaller

trunnions which project out from the sides of the two strips

connecting together a pair of rings CC. The rings and the

connecting strips constitute the circuit which is to be rendered

movable. A current entering by the trunnion + B flows round

the two halves of the circuit, as shown by the arrows, and

comes out at the trunnion -B. In fig. 5 the current is shown

dividing round the two rings; but in all the balances, except

those intended for the largest currents, the current really

circulates first round one ring and then round the other.

To make the ligament, a very large number of exceedingly fine

copper wires laid close together are soldered to the upper

surface of the upper trunnion. The movable circuit CC thus

hangs by two ligaments which are formed of very fine copper

wires. This mode of suspension enables the conductor CC

to vibrate freely like a balance, but at the same time very

large currents can easily be passed through this perfectly

flexible joint. Above and below these movable coils, which

form as it were the two scale- pans of a balance, are fixed

other stationary coils, and the connexions of all these

six coils (shown in fig. 6) are such that when a current

FIG. 6.--Connexions of Kelvin Ampere Balance.

is passed through the whole of the coils in series, forces of

attraction and repulsion are brought into existence which tend

to force one movable coil upwards and the other movable coil

downwards. This tendency is resisted by the weight of a mass of

metal, which can be caused to slide along a tray attached to

the movable coils. The appearance of the complete instrument is

shown by fig. 7. When a current is passed through the instrument

it causes one end of the movable system to tilt downwards, and

the other end upwards; the sliding weight is then moved along

the tray by means of a silk cord until equilibrium is again

established. The value of the current in amperes is then obtained

approximately by observing the position of the weight on the

scale, or it may be obtained more accurately in the following

FIG. 7.--Lord Kelvin's Ampere Balance.

manner:--The upper edge of the shelf on which the weights

slide (see fig. 8) is graduated into equal divisions, and the

weight is provided with a sharp tongue of metal in order that

its position on the shelf may be accurately determined. Since

the current passing through the balance when equilibrium is

obtained with a given weight is proportional to the square

root of the couple due to this weight, it follows that the

current strength when equilibrium is obtained is proportional

to the product of the square root of the weight used

FIG. 8.--Slider of Kelvin Ampere Balance.

and the square root of the displacement distance of this

weight from its zero position. Each instrument is accompanied

by a pair of weights and by a square root table, so that the

product of the square root of the number corresponding to the

position of the sliding weight and the ascertained constant

for each weight, gives at once the value of the current in

amperes. Each of these balances is made to cover a certain

range of reading. Thus the centi-ampere balance ranges from

1 to 100 centi-amperes, the deci-ampere balance from 1 to 100

deci-amperes, the ampere balance from 1 to 100 amperes, the

deka-ampere balance from 1 to 100 amperes, the hecto-ampere

balance from 6 to 600 amperes, and the kilo-ampere balance from

100 to 2500 amperes. They are constructed for the measurement

not only of continuous or unvarying but also of alternating

currents. In those intended for alternating currents, the

main current through the movable coil, whether consisting

of one turn or more than one turn, is carried by a wire

rope, of which each component strand is insulated by silk

covering, to prevent the inductive action from altering the

distribution of the current across the transverse section of

the conductor. To avoid the creation of induced currents,

the coil frames and the base boards are constructed of

slate. Kelvin ampere balances are made in two types--(1) a

variable weight type suitable for obtaining the ampere value

of any current within their range; and (2) a fixed weight

type intended to indicate when a current which can be varied

at pleasure has a certain fixed value. An instrument of the

latter type of considerable accuracy was designed by Lord Kelvin

for the British Board of Trade Electrical Laboratory, and it

is there used as the principal standard ampere balance. A

fixed weight is placed on one coil and the current is varied

gradually until the balance is just in equilibrium. In these

circumstances the current is known to have a fixed value in

amperes determined by the weight attached to the instrument.

Calibration.--The calibration of ammeters is best conducted

by means of a series of standard low resistances and of a

potentiometer (q.v..) The ammeter to be calibrated is placed

in series with a suitable low resistance which may be .1

ohm, .01 ohm, .001 ohm or more as the case may be. A steady

continuous current is then passed through the ammeter and low

resistance, placed in series with one another and adjusted

so as to give any required scale reading on the ammeter.

The potential difference of the ends of the low resistance

is at the same time measured on the potentiometer, and the

quotient of this potential difference by the known value of

the low resistance gives the true value of the current passing

through the ammeter. This can be then compared with the

observed scale reading and the error of the ammeter noted.2

A good ammeter should comply with the following qualifications:--(1)

its readings should be the same for the same current whether

reached by increasing from a lower current or decreasing

from a higher current; (2) if used for alternating currents

its indications should not vary with the frequency within

the range of frequency for which it is likely to be used;

(3) it should not be disturbed by external magnetic fields;

(4) the scale divisions should, if possible, be equal in

length and there should be no dead part in the scale. In

the use of ammeters in which the control is the gravity

of a weight, such as the Kelvin ampere balances and other

instruments, it should be noted that the scale reading or

indication of the instrument will vary with the latitude and

with the height of the instrument above the mean sea-level.

Since the difference between the acceleration of gravity

at the pole and at the equator is about 1/2%, the correction

for latitude will be quite sensible in an instrument which

might be used at various times in high and low latitudes.

If G is the acceleration of gravity at the equator and g

that at any latitude l, then g = G (1 + 0.00513 sin2

l). In the case of an instrument with gravity control, the

latitude at which it is calibrated should therefore be stated.

FIG. 9.-- Edgewise Switchboard Ammeter, Kelvin & James White Ltd.

Switchboard Ammeters.--For switchboard use in electric supply

stations where space is valuable, instruments of the type called

edgewise ammeters are much employed. In these the indicating

needle moves over a graduated cylindrically shaped scale, and they

are for the most part electromagnetic instruments (see fig. 9).

BIBLIOGRAPHY.--Lord Kelvin (Sir W. Thomson), ``New

Standard and Inspectional Electrical Measuring Instruments,''

Proc. Soc. Telegraph Engineers, 1888, 17, p. 540; J. A.

Fleming, A Handbook for the Electrical Laboratory and

Testing Room (2 vols., London, 1901, 1903 ); G. D. Aspinall

Parr, Electrical Measuring Instruments (Glasgow, 1903); J.

Swinburne, ``Electric Light Measuring instruments,'' Proc.

Inst. Civ. Eng., 1891-1892, 110, pt. 4; K. Edgcumbe and F.

Punga, ``Direct Reading Measuring Instruments for Switchboard

Use,'' Jour. Inst. Elec. Eng., 1904, 33, p. 620. (J. A. F.)

1 See J. A. Fleming, A Handbook for the Electrical

Laboratory and Testing Room, vol. i. p. 341 (1901),

also A. Gray, Absolute Measurements in Electricity

and Magnetism, vol. ii. pt. ii. p. 412 (1893).

2 See ``The Electrolysis of Copper Sulphate in Standardizing

Electrical Instruments,'' by A. W. Meikle, read before

the Physical Society of Glasgow University on the 27th

of January 1888, or J. A. Fleming, A Handbook for the

Electrical Laboratory and Testing Room, vol. i. p. 343.

AMPERSAND (a corruption of the mixed English and Latin

phrase, ``and per se and,'' of which there are many dialect

forms, as ``ampussyand,'' or ``amperseand''), the name of

the sign & or &, which is a combination of the letters e,

t, of the Lat. et= and. The sign is now usually called

``short and.'' In old-fashioned primers and nursery books the

name and sign were always added at the end of the alphabet.

AMPHIARAUS, in Greek mythology, a celebrated seer and

prince of Argos, son of Oicles (or Apollo) and Hypermestra,

and through his father descended from the prophet Melampus

(Odyssey, xv. 244). He took part in the voyage of the

Argonauts and in the chase of the Calydonian boar; but his

chief fame is in connexion with the expedition of the Seven

against Thebes, organized by Adrastus, the brother of his

wife Eriphyle, for the purpose of restoring Polyneices to the

throne. Amphiaraus, foreseeing the disastrous issue of the

war, at first refused to share in it; he had, however, promised

Eriphyle when he married her that, in the event of any dispute

arising between her brother and himself, she should decide

between them; and now Eriphyle, bribed by Polyneices with the

fatal necklace given by Cadmus to Harmonia, persuaded him against

his better judgment to set out on the expedition. Knowing his

doom, he bade his sons, Alcmaeon and Amphilochus, avenge his

death upon their mother, upon whom, as he stepped into his

chariot, he turned a look of anger. This scene was represented

upon the chest of Cypselus described by Pausanias (v. 17).

The assault on Thebes was disastrous for the Seven; and

Amphiaraus, pursued by Periclymenus, would have been slain

with his spear, had not Zeus with a thunderbolt opened a chasm

into which the seer, with his chariot, horses and charioteer,

disappeared. Henceforth he was numbered with the immortals and

worshipped as a god. Near Oropus, on the supposed site of his

passing, his sanctuary arose, with healing springs, and an

oracle famous for its interpretation of dreams (Pausanias i.

34). The ruins of this temple, with inscriptions which identify

it, have been discovered and preserved at Mavrodilisi, in the

provinces of Boeotia and Attica. There was another temple

dedicated to him on the road from Thebes to Potniae, and here

was the oracle of Amphiaraus consulted by Croesus and Mardonius.

Homer, Odyssey, xi. 326; Herodotus viii. 134; Pindar,

Olympia, vi., Nemea, ix.; Apollodorus iii. 6.

AMPHIBIA, a zoological term originally employed by Linnaeus

to denote a class of the Animal Kingdom comprising crocodiles,

lizards and salamanders, snakes and Caeciliae, tortoises

and turtles and frogs; to which, in the later editions of

the Systema Naturae he added some groups of fishes. In

the Tableau Elementaire, published in 1795, Cuvier adopts

Linnaeus's term in its earlier sense, but uses the French

word ``Reptiles,'' already brought into use by Brisson, as

the equivalent of Amphibia. In addition Cuvier accepts the

Linnaean subdivisions of Amphibia-Reptilia for the tortoises,

lizards (including crocodiles), salamanders and frogs; and

Amphibia-Serpentes for the snakes, apodal lizards and Caeciliae.

In 17991 Alexandre Brongniart pointed out the wide differences

which separate the frogs and salamanders (which he terms

Batrachia) from the other reptiles; and in 1804 P. A.

Latreille,2 rightly estimating the value of these differences,

though he was not an original worker in the field of vertebrate

zoology, proposed to separate Brongniart's Batrachia from

the class of Reptilia proper, as a group of equal value,

for which he retained the Linnaean name of Amphibia.

Cuvier went no further than Brongniart, and, in the Regne

Animal, he dropped the term Amphibia, and substituted

Reptilia for it. J. F. Meckel,3 on the other hand, while

equally accepting Brongniart's classification, retained the term

Amphibia in its earlier Linnaean sense; and his example has

been generally followed by German writers, as, for instance,

by H. Stannius, in that remarkable monument of accurate and

extensive research, the Handbuch der Zootomie (2nd ed., 1856).

In 1816, de Blainville,4 adopting Latreille's view, divided the

Linnaean Amphibia into Squamiferes and Nudipelliferes,

or Amphibiens; though he offered an alternative arrangement,

in which the class Reptiles is preserved and divided into

two subclasses, the Ornithoides and the Ichthyoides. The

latter are Brongniart's Batrachia, plus the Caeciliae,

whose true affinities had, in the meanwhile, been shown

by A. M. C. Dumeril; and, in this arrangement, the name

Amphibiens is restricted to Proteus and Siren.

B. Merrem's Pholidota and Batrachia (1820), F. S. Leuckart's

Monopnoa and Dipnoa (1821), J. Muller's Squamata and Nuda

(1832), are merely new names for de Blainville's Ornithoides

and Ichthyoides, though Muller gave far better anatomical

characters of the two groups than had previously been put forward.

Moreover, following the indications already given by K. E.

von Baer in 1828,5 Muller calls the attention of naturalists

to the important fact, that while all the Squamata possess

an amnion and an allantois, these structures are absent in

the embryos of all the Nuda. An appeal made by Muller

for observations on the development of the Caeciliae,

and of those Amphibia which retain gills or gill-clefts

throughout life, has unfortunately yielded no fruits.

In 1825 P. A. Latreille6 published a new classification of the

Vertebrata, which are primarily divided into Haematherma.

containing the three classes of Mammifera, Monotremata and

Aves; and Haemacryma, also containing three classes--

Reptilia, Amphibia and Pisces. This division of the

Vertebrata into hot and cold blooded is a curiously retrograde

step, only intelligible when we reflect that the excellent

entomologist had no real comprehension of vertebrate morphology;

but he makes some atonement for the blunder by steadily

upholding the class distinctness of the Amphibia. In this

he was followed by Dr J. E. Gray; but Dumeril and Bibron in

their great work,7 and Dr Gunther in his Catalogue, in

substance, adopted Brongniart's arrangement, the Batrachia

being simply one of the four orders of the class Reptilia.

Huxley adopted Latreille's view of the distinctness of the

Amphibia, as a class of the Vertebrata, co-ordinate with

the Mammalia, Aves, Reptilia and Pisces; and the same

arrangement was accepted by Gegenbaur and Haeckel. In the

Hunterian lectures delivered at the Royal College of Surgeons in

1863, Huxley divided the Vertebrata into Mammals, Sauroids and

Ichthyoids, the latter division containing the Amphibia and

Pisces. Subsequently he proposed the names of Sauropsida

and Ichthyopsida for the Sauroids and Ichthyoids respectively.

Sir Richard Owen, in his work on The Anatomy of Vertebrates,

followed Latreille in dividing the Vertebrata into Haematotherma

and Haematocrya, and adopted Leuckart's term of Dipnoa

for the Amphibia. T. H. Huxley, in the ninth edition of this

Encyclopaedia, treated of Brongniart's Batrachia, under

the designation Amphibia, but this use of the word has not been

generally accepted. (See BATRACHIA.) (T. H. H.; P. C. M.)

1 Brongniart's Essai d'une classification naturelle des reptiles

was not published in full till 1803. It appears in the volume of

the Memoires presentes a l'Institut par divers savans for 1805.

2 Nouveau dictionnaire d'histoire naturelle, xxiv., cited

in Latreille's Fannilles naturelles du regne animal.''

3 System der vergleichenden Anatomie (1821).

4 ``Prodrome d'une Nouvelle Distribution du regne Animal.'' Bulletin

des sciences par la Societe Philomatique de Paris (1816), p. 113.

5 Entwickelungs-Geschichte der Thiere, p. 262

6 Familles naturelles du regne animal.

7 Erpetologie generale, ou histoire

naturelle complete des reptiles (1836).

AMPHIBOLE, an important group of rock-forming minerals, very

similar in chemical composition and general characters to the

pyroxenes, and like them falling into three series according to

the system of crystallization. They differ from the pyroxenes,

however, in having an angle between the prismatic cleavage of

56 deg. instead of 87 deg. ; they are specifically lighter than the

corresponding pyroxenes; and, in their optical characters,

they are distinguished by their stronger pleochroism and

by the wider angle of extinction on the plane of symmetry.

They are minerals of either original or secondary origin;

in the former case occurring as constituents (hornblende) of

igneous rocks, such as granite, diorite, andesite, &c. Those

of secondary origin have either been developed (tremolite)

in limestones by contact-metamorphism, or have resulted

(actinolite) by the alteration of augite by dynamo-metamorphism.

Pseudomorphs of amphibole after pyroxene are known as uralite.

The name amphibole (from the Gr. amfibolos, ambiguous)

was used by R. J. Hauy to include tremolite, actinolite

and hornblende; this term has since been applied to the

whole group. Numerous sub-species and varieties are

distinguished, the more important of which are tabulated

below in three series. The formulae of each will be seen

to conform to the general metasilicate formula R''SiO3.

ORTHORHOMBIC SERIES.

Anthophyllite . . (Mg,Fe)SiO3.

MONOCLINIC SERIES.

Tremolite . . CaMg3(SiO3)4.

Actinolire . . Ca(Mg,Fe)3(SiO3)4.

Cummingtonite . (Fe,Mg)SiO3.

Richterite . . (K2,Na2,Mg,Ca,Mn)SiO3.

Hornblende . . {Ca(Mg,Fe)3(SiO3)4 with

{NaAl(SiO3)2 and (Mg,Fe) (Al,Fe)2SiO6.

MONOCLINIC SERIES--continued.

Glaucophane . . NaAl(SiO3)2.(Fe,Mg)SiO3.

Crocidolite . . NaFe(SiO3)2.FeSiO3.

Riebeckite . . 2NaFe(SiO3)2.FeSiO3.

Arfvedsonite . . Na8(Ca,Mg)3(Fe,Mn)14(Al,Fe)2 Si21O45.

ANORTHIC SERIES.

Aenigmatite . . Na4Fe''9Al Fe'' '(Si,Ti)12O38.

Of these, tremolite, hornblende and crocidolite, as well as the

important varieties, asbestos and jade, are treated under their own

headings. Brief mention only need be here made of some of the

others. Naturally, on account of the wide variations in

chemical composition, the different members vary considerably

in characters and general appearance; the specific gravity, for

example, varies from 2.9 in tremolite to 3.8 in aenigmatite.

Anthophyllite occurs as brownish, fibrous or lamellar masses with

hornblende in mica-schist at Kongsberg in Norway and some other

localities. An aluminous variety is known as gedrite, and a deep

green, Russian variety containing little iron as kupfferite.

Actinolite is an important member of the monoclinic series,

forming radiating groups of acicular crystals of a bright

green or greyish-green colour. It occurs frequently as

a constituent of crystalline schists. The name (from

aktis, a ray, and lithos, a stone) is a translation

of the old German word Strahlstein, radiated stone.

Glaucophane, crocidolite, riebeckite and arfvedsonite form a

somewhat special group of alkali-amphiboles. The two former are

blue fibrous minerals occurring in crystalline schists, and are

the result of dynamo-metamorphic processes; the two latter are

dark green minerals which occur as original constituents of igneous

rocks rich in soda, such as nepheline-syenite and phonolite.

Aenigmatite and its variety cossyrite are rare

minerals forming constituents of igneous rocks of the

nepheline-syenite and phonolite groups. (L. J. S.)

AMPHIBOLITE, the name given to a rock consisting mainly of

amphibole (hornblende), the use of the term being restricted,

however, to metamorphic rocks. Holocrystalline plutonic

igneous rocks composed essentially of hornblende are known as

hornblendites. As is the case with most petrological terms the

exact connotation is not very strictly defined; most authors

allow that accessory minerals such as felspar, garnet, augite

and quartz may be present in variable and often considerable

amount. A foliated or schistose structure, though often

developed in these rocks, is not universal. The hornblende

is usually dark green (actinolite) but may be nearly black

in the hand specimen; in the microscopic slide it is commonly

green of various shades, but may be brown, blue or nearly

colourless. It frequently occurs in elongated bladed prisms,

but rarely shows good crystal faces. The term hornblende-schist

is employed by many writers as nearly synonymous with

amphibolite; most hornblende-schists contain felspar and iron

oxides, while sphene, rutile, quartz and apatite are rarely

absent. Reddish garnets are often conspicuous in the rocks

of this group (garnet-amphibolites), and when in addition

a green-coloured augite occurs the rocks are intimately

allied to the hornblende-eclogites. Epidote also, in yellow

grains, is common (epidote-amphibolites), and in these rocks

the hornblende may be of the blue and richly pleochroic

variety known as glaucophane (glaucophane-epidote-schists).

Hornblende-schists containing dark green ferriferous hornblende

(grunorite-schists) are abundant in some parts of North

America. Tremolite-schists consist essentially of white or

very pale green amphibole; occasionally they are black from

the presence of numerous minute grains of iron oxide or of

graphite. Many tremolite-schists contain much talc and

chlorite, and as these rocks have been derived from peridotites

they not infrequently show residual grains of olivine.

Nephrite (Gr. nefros, a kidney) is a very compact, hardly

schistose amphibolite, consisting of fine interwoven fibres of

hornblende. Among other accessory minerals biotite, chlorite,

talc, scapolite and tourmaline may be mentioned; if abundant they

give rise to special varieties such as biotite-amphibolite, &c.

The amphibolites are typical rocks of the metamorphic group

and as such attain a large development in all regions of

crystalline schists and gneisses such as the Alps, Ardennes,

Harz, Scottish Highlands, and the Lakes district of North

America. They occur in two ways, viz. as large circular or

elliptical areas which mark the site of old plutonic stocks or

bosses of basic rock, and as long narrow strips intercalated

among outcrops of other metamorphic rocks. Regarded from the

point of view of their origin they fall into two groups, the

ortho-amphibolites, which are modified igneous rocks, and the

para-amphibolites, which are altered sediments. The former are

far the more common. Igneous rocks which contain much augite

(e.g. dolerites, gabbros, diabases, pyroxenites and many

peridotites) are usually converted into amphibolites when they

are subjected to pressure and interstitial movements during

earth-folding. If felspar be present also, epidote may

form, while part of the felspar recrystallizes as a species

of the same mineral richer in alkalies or as mica. Olivine

and ilmenite, the other common constituents of these rocks,

may, alone or in conjunction with the above-named minerals,

yield garnet, talc, sphene, rutile, &c. There is little or

no alteration in the bulk composition of the rock, but its

component elements enter into new combinations. Chemical

analysis, accordingly, will often enable us to identify an

igneous rock (diabase, &c.) under the guise of an amphibolite.

The transformation of the rock may be complete, so that no

trace is left of the original structures or minerals. Very

often, however, it is only partial, and by obtaining a

sufficiently large number of specimens a series of intermediate

or transitional stages may be studied; these prove conclusively

the nature of the process, though its causes are less clearly

understood. Green hornblende may be seen gradually replacing

augite, at first in needle-like crystals, for which gradually

more compact masses are substituted. The felspar breaks up

into a mosaic in which albite, epidote or zoisite, quartz and

garnet may often be identified. Biotite and primary hornblende

suffer comparatively little change; olivine disappears, and

garnet, talc and tremolite or anthophyllite take its place.

The original structures of this group of rocks (ophitic,

porphyritic, poikilitic, vesicular, &c.) gradually fade away,

and merge into those of the metamorphic amphibolites. Even

when the greater part of the rock mass has suffered complete

reconstruction, kernels or phacoids may remain, showing

the old igneous structures, though the minerals are greatly

altered. The transitional stages from gabbro or diabase to

amphibolite are so common that they form a widespread and

important group of rocks, which have been described under

the names greenstone, greenstone-schist, flaser-gabbro,

saussurite- gabbro, meta-diabase, &c. The ortho-amphibolites

also include a small group of igneous rocks, which have a

foliated or banded structure due to movements and pressure

during consolidation, e.g. foliated diorite or diorite-schist.

The sedimentary amphibolites or para-amphibolites, less common

than those above described, are frequent in some districts,

such as the northern Alps, southern highlands of Scotland, Green

Mountains, U.S.A. Many of them have been ash-beds, and their

conversion into hornblende-schists follows exactly similar

stages to those exemplified by basic crystalline igneous

rocks. Others have been greywackes of varied composition with

epidote, chlorite, felspar, quartz, iron oxides, &c., and

may have been mixed with volcanic materials, or may be partly

derived from the disintegration of basic rocks. When they are

most metamorphosed they are often very hard to distinguish from

igneous hornblende-schists; yet they rarely fail to reveal signs

of bedding, pebbly structure, sedimentary banding and gradual

transition into undoubtedly sedimentary types of gneiss and

schist. Deposits containing dolomite and siderite also readily

yield amphibolites (tremolite-schists, grunorite-schists,

&c.) especially where there has been a certain amount of

contact metamorphism by adjacent granitic masses. (J. S. F.)

AMPHIBOLOGY, or AMPHIBOLY (Gr. ampibolia), in logic,

a verbal fallacy arising from ambiguity in the grammatical

structure of a sentence (Aristot., Organon,Soph., El.,

chap. iv.). It occurs frequently in poetry, owing to the

alteration for metrical reasons of the natural order of

words; Jevons quotes as an example Shakespeare, Henry

VI.: ``The duke yet lives that Henry shall depose.''

AMPHICTYONY (Gr. amfiktuonia, i.e. a body composed

of amfiktiones, amfiktuones, ``dwellers around''),

an association of ancient Greek communities centring in a

shrine. As the extant sources do not define the term,

and as they apply it to but five or six associations, the

majority of which are little known, modern scholars are in

doubt as to the essential character of the institution, and

hesitate therefore to extend the name beyond this limited

list. The word itself indicates that the association primarily

comprised neighbours, though the Delphic amphictyony came in

time to include relatively distant communities (Strabo ix.

3, 7). For the origin of the institution it is safe to assume

that neighbouring communities, whether tribes (ethne) or

cities, desiring friendly intercourse with one another chose

the sanctuary of some deity conveniently situated, at which

to hold their periodical festival for worship and their fair

for the interchange of goods. If the limited use of the word

according to our sources is not purely accidental, at all

events there were many Greek leagues, not expressly termed

amphictyonies, which had the characteristics here stated.

The Delian amphictyony probably reached the height of its

splendour early in the 7th century B.C. The Hymn to the Delian

Apollo, composed about that time, celebrates the gathering

of the Ionians with their wives and children at the shrine of

their god on the island of Delos, to worship him with music,

dancing and gymnastic contests (vv. 146-164; cf. Thuc. iii.

104). The later misfortunes of the Ionians caused a decline of the

festival. Peisistratus, taking possession of Delos, seems to

have used the sanctuary as a means of extending his political

influence. When after the great war with Persia the Aegean

cities under the leadership of Athens united in a political

league (477 B.C.), they chose as its centre the temple of the

Delian Apollo, doubtless through a desire to connect the new

alliance with the associations of the old amphictyony. How far

the council and other institutions of the Delian confederacy

were based upon the amphictyonic organization cannot be

determined. The removal of the treasury to Athens in 454 B.C.

deprived Delos of political importance, though the amphictyony

continued. The council gradually dwindled, and probably

came to an end without formal abolition. In 426 B.C. the

Athenians purified the island and instituted a great festival

to be held under their presidency every four years (Thuc. iii.

104). In 422 they expelled the Delians (Thuc. v. 1). At the

end of the Peloponnesian War Athens was deprived of Delos

along with her other possessions, but she appears to have

regained control of the island after the victory of Cnidus

(394). An inscription of 390 B.C. proves that at this date

Athenian authority had been restored. The affairs of the temple

were managed by a board of five Athenian amphictyons, assisted

by some Delian officials (inscrr. in Bull. Hell. viii. 284,

304, 307 f.); and in the 4th century we again hear of a council

in addition to the board (CIG. i. 158). At this time the

amphictyony is known to have embraced both the Athenians and

the inhabitants of the Cyclades; but a strong Delian party

bitterly opposed Athenian rule (cf. inscr. in Bull. Hell.

iii. 473 f.), which came to an end with the supremacy of

Macedon. The dissolution of the amphictyony soon followed.

Far more famous is the Delphic, or more strictly, the

Pylaeic-Delphic, amphictyony. It was originally composed of

twelve tribes dwelling round Thermopylae--the Thessalians,

Boeotians, Dorians, Ionians, Perrhaebians, Magnetes, Locrians,

Oetaeans, Phthiotes, Mahans, Phocians (Aeschin. ii. 116), and

Dolopians (Paus. x. 8. 2). The name of the council (pylaea)

and of one set of deputies (pylagori), together with the

important place held in the amphictyony by the temple of Demeter

at Anthela, near Thermopylae, suggests that this shrine was

the original centre of the association. How and when Delphi

became a second centre is quite uncertain. The council of the

league included deputies of two different kinds--pylagori

and hieromnemones. the latter were twenty-four in number,

two from each tribe. As the league was originally made up of

neighbours, the Dorian tribe must have comprised simply the

inhabitants of Doris; the Locrians were probably the eastern

(Opuntian) branch; and the Ionians were doubtless limited to

the adjacent island of Euboea. Afterwards, by affiliating

themselves to Doris, the Peloponnesian Dorians gained

admission, and Athens must have entered as an Ionian city

before the first Sacred War. Henceforth Athens monopolized one

of the two Ionian votes, while the other passed in rotation

among the remaining Ionic, perhaps only among the Euboeic,

cities. In the same way Doris held one Dorian vote and

the other passed in rotation among the Dorian cities of

Peloponnesus; and the east and west Locrians came to have one

each. When after the second Sacred War the Phocians were

expelled, Macedon received their two votes (346 B.C.)

About the same time the Perrhaebians and the Dolopians were

deprived of half their representation, and the two votes

were transferred to the Delphians (inscrr. in N. Jahrb. f.

cl. Philol. clv. 742, cf. 743, 753; Bull. Hell. xxi.

322, cf. 325; Bourguet, Sanct. Pyth. 145, 147). In the

following century the Aetolians gained such dominance in the

amphictyony as to convert the council into an organ of their

league. Recent research has made it appear certain (cf.

Pomptow, ib. 754 ff.) that they were never formally admitted

to membership, but that they maintained their supremacy in the

council (Livy xxxi. 32. 3; Polyb. iv. 25. 8) by controlling

the votes of their allies, who-- called Aetolians in the

inscriptions--were often in the majority. They made no material

change in its composition, which, accordingly, after the

dissolution of their league by the Romans is found to be nearly

as it was after the second Sacred War. A few minor changes

came in under the supremacy of the Roman republic; and finally

Augustus increased the number of votes to thirty, and distributed

them according to his pleasure. In the age of the Antonines

the association was still in existence (paus. x. 8. 4 f.).

Although the hieromnemones of the Thessalians, who held the

presidency, and perhaps of a few other communities, must have

been elected, the office was ordinarily, as at Athens, filled

by lot. As a rule they were renewed annually (Aristoph.

Clouds, 623 f.; Foucart, in Bull. Hell. vii. 411, 413

f.). Each hieromnemon was accompanied by two pylagori,

elected semi-annually (Demosth. xviii. 149; Aeschin.

iii. 115; Tim. Lex. Plat., s.v. 'Amfiktuones), and

representing the same tribe, though not necessarily the same

city. On one occasion Athens is known to have sent three.

The hieromnemones were formally superior, but because of the

method of appointment they were necessarily men of mediocre

ability, inexperienced in speaking and public business, and

for that reason they readily became the tools of the pylagori,

who were orators and statesmen. In the literary sources,

accordingly, the latter are rightly given credit for the acts

of the council; it was the pylagori who set a price on the

head of the traitor Ephialtes ( Herod. vii. 213 ), and who

on the motion of Themistocles rejected the proposition of

Lacedaemon for the expulsion of the states which had sided

with Persia (Plut. Them. 20). The pylagori had a right

to propose measures and to take part in the deliberations;

they as well as the hieromnemones were required to take the

juror's oath; and the acts of the council were inscribed

officially as resolutions of the hieromnemones and pylagori

conjointly. The hieromnemon, however, cast the vote of his

community, though in the record his two pylagori were made

equally responsible for it. The necessary inference from these

facts is that the vote was determined by a majority of the three

deputies (inscr. in Bull. Hell. xxvii. 106-111, A 20-33; B

1-10). The council decided all questions which fell within its

competence. Matters of greater importance, as the levy of an

extraordinary fine on a state or the declaration of a sacred

war, it presented in the form of a resolution to an assembly

(ekklesia), composed of the deputies, the amphictyonic

priests, and any other citizens of the league who chanced

to be present (Aeschin. iii. 124; cf. Hyp. iv. 7, 26

f.). This assembly was relatively unimportant, however,

and is mentioned only by the two authorities here cited.

It is now well established by epigraphic evidence (Bull.

Hell. vii. 412 f., 417; Pomptow, in N. Jahrb. f. cl.

Philol. cxlix. 826-829) that the amphictyons met both in

the spring and in the autumn at Delphi, and the literary

sources should alone be sufficient authority for meetings

in the same seasons at Thermopylae (Hyp. iv. 7, 25 ff.;

Strabo ix. 3, 7, 4, 17; Harpocration, s.v. Pulai.)

It is known, too, that the meeting at Thermopylae followed

that at Delphi (inscr. in Bull. Hell. xxiv. 136 f.).

The primary function of the council was to administer the

temporal affairs of the two shrines, of which the sanctuary

of Apollo at Delphi claimed by far the greater share of

attention. The hieromnemones were required periodically to

inspect the lands belonging to this god, to punish those who

encroached, and to see that the tenants rendered their quota

of produce; and the council held the states responsible for

the right performance of such duties by their respective

deputies (CIA. ii. 545; inscr. in Bull. Hell. vii. 428

f.). Another task of the council was to supervise the treasury,

to protect it from thieves, and by investments to increase

the capital (Strabo ix. 3, 7; Isoc. xv. 232; Demosth. xxi.

144; Plut. Sull. 12). Naturally, too, it controlled the

expenditure. We find it, accordingly, in the 6th century

B.C. contracting for the rebuilding of the Delphic temple

after it had been destroyed by fire (Herod. v. 62; Paus. x. 5.

13), and in the 4th century creating an Hellenic college of

temple-builders for the purpose (inscrr. in Bull. Hell.

xx. 202 f., 206, xxi. 478, xxiv. 464), adorning the interior

with statues and pictures (Diod. xvi. 33), inscribing the

proverbs of the Seven Sages on the walls (Paus. x. 24. 1),

bestowing crowns on benefactors of the god (CIG. i. 1689 b),

preparing for the Pythian games, awarding the prizes (Pind.

Pyth. iv. 66, x. 8 f.), instituting a board of treasurers

(inscr. in Bourguet, Sanct. Pyth. 175 ff.) and issuing

coins. It was also in the material interest of Apollo that

the council passed a law which forbade the Greeks to levy tolls

on pilgrims to the shrine (Aeschin. iii. 107; Strabo ix. 3,

4), and another requiring the amphictyonic states to keep in

repair their own roads which led towards Delphi (CIA. ii.

545). A law of great interest, dating from the beginning

of the institution, imposed an oath upon the members of the

league not to destroy an amphictyonic city or to cut it off

from running water in war or peace; but to wage war upon

those who transgressed this ordinance, to destroy their

cities, and to punish any others who by theft or plotting

sought to injure the god (Aeschin. ii. 115). In this

regulation, which was intended to mitigate the usages of

war amongst the members of the league, we have one of the

origins of Greek interstate law. Though other regulations

were made to secure peace at the time of the festival

(Dion. Hal. iv. 25. 3), and though occasionally the council

was called upon to arbitrate in a dispute (cf. Demosth.

xviii. 135), no provision was made to compel arbitration.

For the enforcement of such laws and for administrative

efficiency in general it was necessary that the council should

have judicial power. As jurors the deputies took an oath to

decide according to written law, or in cases not covered by

law, according to their best will and judgment (CIA. ii.

545). The earliest known amphictyonic penalty was the

destruction of Crisa for having levied tolls on pilgrims

(Aeschin. iii. 107; Strabo ix. 3, 4; cf. Paus. x. 37.

5-8). This offence was the cause of the first Sacred War.

The second and third Sacred Wars, fought in the 4th century

B.C., were waged by the amphictyons against the Phocians

and the Amphissaeans respectively for alleged trespassing on

the sacred lands (Aeschin. iii. 124, 128; Diod. xvi. 23, 31

f.). In the 5th century the council fined the Dolopians for

having disturbed commerce by their piracy (Plut. Cim. 8),

and in the 4th century the Lacedaemonians for having occupied

the citadel of Thebes in time of peace (Diod. xvi. 23, 29).

The judgments of the council were sometimes considered unfair,

and were occasionally defied by the states affected. The

Lacedaemonians refused to pay the fine above mentioned; the

Athenians protested against the treatment of Amphissa, and were

slow in accepting the decisions given under the influence of

Macedon. The inability of the council to enforce its

resolutions was chiefly due to its composition; the majority

of the communities represented were even in combination no

match for individual cities like Athens, Sparta or Thebes.

The council was a power in politics only when manipulated by

a great state, as Thebes, Macedon or Aetolia, and in such a

case its decrees were most likely to give offence by their

partisanship. Although the council sometimes championed

the Hellenic cause, as could any association or individual,

it never acquired a recognized authority over all Greece;

and notwithstanding its frequent participation in political

affairs, it remained essentially a religious convocation.

In addition to the three associations thus far mentioned

there was an amphictyony of Onchestus (Strabo ix. 2, 33).

It may be inferred from a comparison of Paus. iv. 5. 2 with

Herod. vi. 92 that there was an amphictyony of Argos of

which Epidaurus and Aegina were members. An amphictyony

of Corinth has, with less justification, been assumed on

the strength of a passage in Pindar (Nem. Od. vi. 40-42).

AUTHORITIES.--Foucart, ``Amphictyones,'' in Daremberg and

Saglio, Dict. d. antiq. grecq. et rom. (1873) i. 235-238; F.

Qauer, ``Amphiktyonia,'' in Pauly-Wissowa, Realencycl. d.

cl. Altertumswiss. (1894) i. 1904-1935; Pomptow, Fasti

Delphici, ii. in Neue Jalhrb. f. cl. Philol. (1894) cxlix.

497-558, clv. (1897) 737-763, 783-848; E. A. Freeman, History

of Federal Government in Greece and Italy (2nd ed., London

and New York, 1895), 95-111; W. S. Ferguson, Schomann-Lipsius,

Griechische Alterthumer (1902), ii. 29-44; E. Bourguet,

L'Administration financiere du sanctuaire pythioue au IVe

siecle avant J.-C (Paris, 1905). The earlier literature

has been deprived of a great part of its value by recent

discoveries of inscriptions, many of which may be found in

the Bulletin de correspondance hellenique, iii. vii.

viii. x. xx. xxi. xxiv. xxvi. xxvii., edited with commentary

chiefly by Bourguet, Colin, Foucart and Homolle. See also

H. Collitz, Sammlung d. griech. Dialekt-Inschriften, ii.

p. 643 ff. and Nos. 2508 ff., edited by Baunack. (G. W. B.)

AMPHILOCHUS, in Greek legend, a famous seer, son of Amphiaraus

and Eriphyle and brother of Alcmaeon. According to some

he assisted in the murder of Eriphyle, which, according to

others, was carried out by Alcmaeon alone (Apollodorus iii.

6, 7). He took part in the expedition of the Epigoni against

Thebes and in the Trojan War. After the fall of Troy he

founded, in conjunction with Mopsus, another famous seer,

the oracle of Mallos in Cilicia. The two seers afterwards

fought for its possession, and both were slain in the

combat. Amphilochus is also said to have been killed by

Apollo (Strabo xiv. 675, 676). According to another story,

he returned to Argos from Troy, but, being dissatisfied

with the condition of things there, left it for Acarnania,

where he founded Amphilochian Argos on the Ambracian

gulf. He was worshipped at Oropus, Athens and Sparta.

Strabo xiv. pp. 675, 676; Thucydides ii. 68; Pausanias i. 34, iii. 15.

AMPHION and ZETHUS, in ancient Greek mythology, the twin

sons of Zeus by Antiope. When children, they were exposed

on Mount Cithaeron, but were found and brought up by a

shepherd. Amphion became a great singer and musician, Zethus

a hunter and herdsman (Apollodorus iii. 5). After punishing

Lycus and Dirce for cruel treatment of Antiope (q.v.),

they built and fortified Thebes, huge blocks of stone forming

themselves into walls at the sound of Amphion's lyre (Horace,

Odes, iii. 11). Amphion married Niobe, and killed himself

after the loss of his wife and children (Ovid, Metam. vi.

270). The brothers were buried in one grave and worshipped

as the Dioscuri ``with white horses'' (Eurip. Phoen. 609).

AMPHIOXUS, or LANCELET, the name of small, fish-like,

marine creatures, forming the class Cephalochorda, of the

phylum Vertebrata. Lancelets are found in brackish or salt

water, generally near the coast, and have been referred to

several genera and many species. They were first discovered

by P. S. Pallas in 1778, who took them to be slugs and

described them under the name Limax lanceolatus. The

true position in the animal kingdom was first recognized in

1834 by O. G. Costa, who named the genus Branchiostoma,

and it has since been dealt with by many writers.

The theoretical interest of Amphioxus depends upon a variety of

circumstances. In its manner of development from the egg, and

in the constitution of its digestive, vascular, respiratory

(branchial), excretory, skeletal, nervous and muscular systems

it exhibits what appears to be a primordial condition of

vertebrate organization, a condition which is, in fact, partly

recapitulated in the course of the embryonic stages of craniate

vertebrates. In comparative morphology it provides many

illustrations of important biological principles (such, for

example, as substitution and change of function of organs),

and throws new light upon, or at least points the way to

new ideas of, the primitive relations of different organic

systems in respect of their function and topography. One of

the most puzzling features in its structure, and, at the same

time, one of the greatest obstacles to the view that it is

essentially primitive and not merely a degenerate creature,

is the entire absence of the paired organs of special sense,

olfactory, optic and auditory, which are so characteristic

of the higher vertebrates. Although it is true that there

is a certain amount of gradation in the degree of development

to which these organs have attained in the various orders,

yet it is hardly sufficient to enable the imagination to

bridge over the gap which separates Amphioxus from the

lowest fishes in regard to this feature of organization.

Classification.--On account of the absence of anything in

the nature of a skull, Amphioxus has been regarded as the

type of a division, Acrania, in contrast with the Craniata

which comprise all the higher Chordata. The ordinal name

for the genera and species of Amphioxus is Cephalochorda,

the term referring to the extension of the primary backbone

or notochord to the anterior extremity of the body; the

family name is Branchiostomidae. The amount of generic

divergence exhibited by the members of this family is not great

in the mass, but is of singular interest in detail. There

are two principal genera--1. Branchiostoma Costa, having

paired sexual organs (gonadic pouches); 2. Heteropleuron

Kirkaldy, with unilateral gonads. Of these, the former

includes two subgenera, Amphioxus (s. str.) Yarrell and

Dolichorhynchus Willey. The species belonging to the

genus Heteropleuron are divided among the three subgenera

Paramphioxus Haeckel, Epigonichthys Peters, and Asymmetron

Andrews. The generic characters are based upon definite

modifications of form which affect the entire facies of the

animals, while the specific diagnoses depend upon minor

characters, such as the number of myotomes or muscle-segments.

Habits and Distribution.--With regard to its habits, all that

need be said here is that while Amphioxus is an expert swimmer

when occasion requires, yet it spends most of its time burrowing

in the sand, in which, when at rest, it lies buried with head

protruding and mouth wide agape. Its food consists of microscopic

organisms and organic particles; these are drawn into the mouth

FIG. 1.--Epigonichthys cultellus from below and from the left

side. (Slightly altered from Kirkaldy.) rm and lm, Right and

left metapleur; at, atriopore; an, anus; e, ``eyespot''

at anterior end of neurochord projecting beyond the myotomes

(my); n, notochord; rgo, gonads of right side only showing

through by transparency; go 20, the last gonad; dfr, dorsal

fin with fin chambers and fin rays; vfc, ventral fin chambers.

together with currents of water induced by the action of the

vibratile cilia which are abundant along special tracts on

the sides and roof of the vestibule of the mouth and in the

walls of the perforated pharynx (``ciliary ingestion'').

Amphioxus favours a littoral habitat, and rarely if ever

descends below the 50-fathom line. Species occur in all

seas of the temperate, tropical and subtropical zones. The

European species, A. lanceolatus, is found in the Black

and Mediterranean Seas, and on the coasts of France, Great

Britain and Scandinavia, while a closely allied species or

subspecies, A. caribaeus, frequents the Caribbean region

from Chesapeake to La Plata. A. californiensis occurs

on the coast of California, and A. belcheri extends its

area of distribution from Queensland through Singapore to

Japan. A recently described species, Dolichorhynchus indicus,

characterized by the great length of the praeoral lobe or

snout, has been dredged in the Indian Ocean. Paramphioxus

bassanus occurs on the coast of Australia from Port Phillip

to Port Jackson; P. cingalensis at Ceylon. Epigonichthys

cultellus (fig. 1) inhabits Torres Strait, and has also been

FIG. 2.--Amphioxus lanceolatus, Yarrell (Branchiostoma

lubricum, Coste). (From Ray Lankester.) (1) Lateral view

of adult, to show general form, the myomeres, fin rays and

gonads. A, Oral tentacles 28 to 32 in full-grown animals, 20

to 24 in half-grown specimens); B, praeoral hood or praeoral

epipleur; C, plicated ventral surface of atrial chamber;

D1, D17, D26, gonads, twenty-six pairs, coincident

with myotomes 10 to 36; E, metapleur or lateral ridge on

atrial epipleur; F, atripore, coincident with myotome 36;

G1, G15, G34, double ventral fin rays, extending from

myotomes 37 to 52, but having no numerical relation to

them; H, position of anus, between myotomes 51 and 52; I,

notochord, projecting beyond myotomes; K7, K27, K62,

myotomes or muscular segments of body-wall, 62 in number;

L100, L230, L253, dorsal fin rays, about 250 in

number, the hard substance of the ray being absent at the

extreme ends of the body (these have no constant numerical

relation to the myomeres); M, notochord as seen through the

transparent myotomes, the thin double-lined spaces being the

connective-tissue septa and the broader spaces the muscular

tissue of the myotomes; N, position of brown funnel of left

side (atrio-coelomic canal); O, nerve tube resting on notochord.

(2) Dissection of Amphioxus. By a horizontal incision on

each side of the body a large ventral area has been separated

and turned over, as it were on a hinge, to the animal's left

side. The perforated pharyngeal region has then been detached

from the adherent epipleura or opercular folds (wall of atrial

or branchial chamber) by cutting the fluted pharyngo-pleural

membrane d, and separated by a vertical cut from the

intestinal region. a, Edge of groove formed by adhesion

of median dorsal surface of alimentary canal to sheath of

notochord; b, median dorsal surface of alimentary canal;

c, left dorsal aorta; cc, single dorsal aorta, formed by

union of the two anterior vessels; cc', same vessel resting

on intestine; d, cut edge of pharyngo-pleural folds of

atrial tunic, really the original outer body-wall before the

downgrowth of epipleura; d', atrial tunic (original body-wall)

at non-perforate region, cut and turned back so as to expose

peri-enteric coelom and intestine r; e', upstanding folds

of body-wall (pharyngo-pleural folds) on alternate bars of

perforate region of body; f, atrio-coelomic canals or brown

funnels (collar-pores of Balanoglossus); g, cavity of

a gonad-sac; m, cut musculature of body-wall; n, anus;

o, post-atrioporal extension of atrial chamber in form

of a tubular caecum; p, atriopore; q, hepatic caecum;

r, intestine; s, coelom; t, area of adhesion between

alimentary canal and sheath of notochord; v, atrial chamber

or branchial cavity; w, post-atrioporal portion of intestine;

x, canals of metapleura exposed by cutting; E, probe passing

through atriopore into atrial or branchial chamber; FF', probe

passing from coelom, where it expands behind the atriopore,

into narrower peri-enteric coelom of praeatrioporal region.

(3) Portion of (2) enlarged to show atrio-coelomic canals

(``brown funnels'' of Lankester). Lettering as in (2).

(4)Section taken transversely through praeoral region near

termination of nerve tube. a, Olfactory ciliated pit on

animal's left side, its wall confluent with substance of

nerve tube; b, pigment spot (rudimentary eye) on anterior

termination of nerve tube; c, first pair of nerves in

section; d, fin ray; e, myotome; f, notochord; g, space

round myotome (?artifact or coelom); h, subchordal canal (?

blood-vessel); i, a symmetrical epipleura of praeoral hood.

found at Ternate. Asymmetron lucayanum is the Bahaman

representative of the family, with a subspecies, A. caudatum,

in the South Pacific from New Guinea to the Loyalty Islands. The

Peruvian species, Branchiostoma elongatum, with nearly eighty

myotomes, cannot at present be assigned to its proper subgenus.

External Form.--The following description, unless otherwise

stated, refers to A. lanceolatus. Amphioxus is a small

fish-like creature attaining a maximum length of about 3

in., semitransparent in appearance, showing iridescent play of

colour. The body is narrow, laterally compressed and pointed

at both ends. The main musculature can be seen through the thin

skin to be divided into about sixty pairs of muscle-segments

(myotomes) by means of comma-shaped dissepiments, the

myocommas, which stretch between the skin and the central

skeletal axis of the body. These myotomes enable it to swim

rapidly with characteristic serpentine undulations of the

body, the movements being effected by the alternate contraction

and relaxation of the longitudinal muscles on both sides.

Apparently correlated with this peculiar locomotion is the

anatomical fact of the alteration of the myotomes on the two

sides. Symmetrical at their first appearance in the embryo,

the somites (from which the myotomes are derived) early undergo

a certain distortion, the effect of which is to carry the

somites of the left side forwards through the length of one

half-segment. For example, the twenty-seventh myotome of

the left side is placed opposite to the twenty-sixth myocomma

of the right side. The back of the body is occupied by a

crest, called the dorsal fin, consisting of a hollow ridge,

the cavity of which is divided into about 250 compartments

or fin chambers, into each of which, with the exception

of those near the anterior and posterior end of the body,

projects a stout pillar composed of characteristic laminar

tissue, the fin ray. The dorsal crest is continued round

both extremities, becoming expanded to form the rostral

fin in front and the caudal fin behind. Even in external

view, careful inspection will show that the body is divisible

into four regions, namely, cephalic, atrial, abdominal and

caudal. The cephalic region includes the rostrum or praeoral

FIG.--Transverse sections of amphioxus. (From Lankester.)

A. Section through region of atrio-coelomic canal s, v.

B . Section in front of mouth; the right and left sides

are transposed. a, Cavity surrounding fin ray; a', fin

ray; b, muscular tissue of myotome; c, nerve- cord;

d, notochord; c, left aorta; f thickened ridges of

epithelium of praeoral chamber (Rader organ); g, coiled

tube lying in a coelomic space on right side of praeoral

hood, apparently an artery; h, cuticle of notochord; i,

connective-tissue sheath of notochord; k, median ridge of

skeletal canal of nerve-cord; l, skeletal canal protecting

nerve-cord; m, inter-segmental skeletal septum of myotome;

n, subcutaneous skeletal connective tissue; o, ditto of

metapleur (this should be relatively thicker than it is);

q, subcutaneous connective tissue of ventral surface of

atrial wall (not a canal, as supposed by Stieda and others);

r, epiblastic epithelium; s gonad-sac containing ova;

t, pharyngeal bar in section, one of the pharyngo-pleural

fold and coelom; v, atrio-coelomic funnel; w, so-called

``dorsal'' coelom; x, lymphatic space or canal of metapleur;

y, sub-pharyngeal vascular trunk; z, blood-vessel (portal

vein) on wall of hepatic caecum; aa, space of atrial or

branchial chamber; bb, ventral groove of pharynx (anteriorly

this takes the form of a ridge); cc, hyperbranchial groove

of pharynx; dd, lumen or space of hepatic caecum; ee,

narrow coelomic space surrounding hepatic caecum; ff)

lining cell-layer of hepatic caecum; gg, inner face of a

pharyngeal bar clothed with hypoblast, the outer face covered

with epiblast (represented black); hh, a main pharyngeal bar

with projecting pharyngeal fold (on which the reference line

rests) in section, showing coelomic space beneath the black

epiblast; ii, transverse ventral muscle of epipleura; kk,

raphe or plane of fusion of two down-grown epipleura; ll,

space and nucleated cells on dorsal face of notochord; mm,

similar space and cells on its ventral face. lobe and the

mouth. As already stated, the notochord extends beyond the

mouth to the tip of the rostrum. The mouth consists of two

portions, an outer vestibule and an inner apertura oris;

the latter is surrounded by a sphincter muscle, which forms

the so-called velum. The vestibule of the mouth is the space

bounded by the oral hood; this arises by secondary downgrowth

of lid-like folds over the true oral aperture, and is provided

with a fringe of tentacular cirri, each of which is supported

by a solid skeletal axis. The oral hood with its cirri has a

special nerve supply and musculature by which the cirri can be

either spread out, or bent inwards so that those of one side

may interdigitate with those of the other, thus completely

closing the entrance to the mouth. The velum is also provided

with a circlet of twelve tantacles (in some species sixteen)

which hang backwards into the pharynx; these are the velar

tentacles. The atrial region extends from the mouth over about

two-thirds of the length of the body, terminating at a large

median ventral aperture, the atriopore; this is the excurrent

orifice for the respiratory current of water and also serves

for the evacuation of the generative products. This region

FIG. 4.--Amphioxus lanceolatus laid open ventrally.

(After Rathke, slightly altered.) m, Mouth appearing as

an elongated slit when relaxed (as in the lamprey); p,

perforated pharynx; e, endostyle; g, gonads; l, liver;

at, level of atriopore; i, intestine; an, anus.

In this species the atrium is produced as an asymmetrical

blind pouch behind the atriopore as far as the anus.

is really the branchiogenital region, although the fact

is not apparent in external view. The ventral side of the

body in the atrial region is broad and convex, in the atrial

region is broad and convex, so that the body presents the

appearance of a spherical triangle in transverse section, the

apex being formed by the dorsal fin and the angles bordered

by two hollow folds, the metapleural folds, each of which

contains a continuous longitudinal lymph-space, the metapleural

canal. In the genus Branchiostoma the metapleural folds

terminate symmetrically shortly behind the atriopore, but in

Heteropleuron the right metapleur passes uninterruptedly into

the median crest of the ventral fin (fig. 1). In this connexion

it may also be mentioned that in all cases the right half of

the oral hood is directly continuous with the rostral fin (fig.

2). The abdominal region comprises a short stretch of body

between atriopore and anus, the termination of the alimentary

canal. It is characterized by the presence of a special

development of the lophioderm or median fin-system, namely,

the ventral fin, which is composed of two portions, a lower

keel-like portion, which underlies an upper chambered portion,

each chamber containing typically a pair of gelatinous fin

rays. Finally, the caudal region comprises the post-anal

division of the trunk. The keel of the ventral fin is continued

past the anus into the expanded caudal fin, and so it happens

that the anal opening is displaced from the middle line to

the left side of the fin. In Asymmetron the caudal region

is remarkable for the curious elongation of the notochord,

which is produced far beyond the last of the myotomes.

Alimentary, Respiratory and Excretory Systems.--Although

the function of the two latter systems of organs is the

purification of the blood, they are not usually considered

together, and it is therefore the more remarkable that their

close association in Amphioxus renders it necessary to

treat them in common. The alimentary canal is a perfectly

straight tube lined throughout by ciliated epithelium. As food

particles pass in through the mouth they become enveloped in a

slimy substance (secreted by the endostyle) and conveyed down

the gut by the action of the vibratile cilia as a continuous

food-rope, the peristaltic movements of the gut-wall being very

feeble. The first part of the alimentary canal consists of

the pharynx or branchial sac, the side walls of which are

perforated by upwards of sixty pairs of elongated slits, the

gill-clefts. Each primary gill-cleft becomes divided into two

by a tongue-bar which grows down secondarily from the upper

wall of the cleft and fuses with the ventral wall. New clefts

continue to form at the posterior end of the pharynx during

the adult life of the animal. The gill-clefts open directly

from the cavity of the pharynx into that of the atrium, and

so give egress to the respiratory current which enters the

mouth with the food (fig. 4). The atrium or atrial chamber

is a peripharyngeal cavity of secondary origin effecting

the enclosure of the gill-clefts, which in the larva opened

directly to the exterior. The atrium is thus analogous to the

opercular cavity of fishes and tadpoles, and, as stated above,

remains in communication with the exterior by means of the

atriopore. The primary and secondary bars which separate

and divide the successive gill-clefts from one another are

traversed by blood-vessels which run from a simple tubular

contractile ventral branchial vessel along the bars into a

dorsal aorta. The ventral branchial vessel lies below the

hypobranchial groove or endostyle; and is the representative

of a heart. As water for respiration streams through the

clefts, gaseous interchange takes place between the circulating

colourless blood and the percolating water. The pharynx

projects freely into the atrium; it is surrounded at the sides

and below by the continuous atrial cavity, but dorsally it is

held in position in two ways. First, its dorsal wall (which

is grooved to form the hyperpharyngeal groove) is closely

adherent to the sheath of the notochord; and secondly, the

pharynx is attached through the intermediation of the primary

bars. These are suspended to the muscular body- wall by

a double membrane, called the ligamentum denticulatum,

which forms at once the roof of the atrial chamber and the

floor of a persistent portion of the original body-cavity

or coelom (the dorsal coelomic canal on each side of the

pharynx). The ligamentum denticulatum is thus lined on

one side by the epiblastic atrial epithelium, and on the

other by mesoblastic coelomic epithelium. Now this ligament

is inserted into the primary bars some distance below the

upper limits of the gill-clefts, and it therefore follows

that, corresponding with each tongue-bar, the atrial cavity

is produced upward beyond the insertion of the ligament into

a series of bags or pockets, which may be called the atrial

pouches. At the top of each of these pouches there is a minute

orifice, the aperture of a small tubule lying above each pouch

in the dorsal coelom. These tubules are the excretory tubules

or nephridia. They communicate with the coelom by several

openings or nephrostomes, and with the atrium by a single

opening in each case, the nephridiopore. It is important to

emphasize the fact that in Amphioxus the excretory tubules

are co-extensive with the gill-clefts. The perforated pharynx

terminates some distance in front of the atriopore. At the

level of its posterior end a pair of funnelashaped pouches

of the atrium are produced forwards into the dorsal coelom.

These are the atrial coelomic funnels or brown funnels, so

called on account of the characteristic pigmentation of their

walls. There are reasons for supposing that these funnels

are vestiges of an ancient excretory system, which has

given way by substitution to the excretory tubules described

above. In the same region of the body, namely, close behind

the pharynx, a large diverticulum is given off from the

ventral side of the gut. This is the hepatic caecum (fig.

2,2,q, fig. 4, l), which is quite median at its first

origin, but, as it grows in length, comes to lie against

the right wall of the pharynx. Although within the atrial

cavity, it is separated from the latter by a narrow coelomic

space, bounded towards the atrium by coelomic and atrial

epithelium. No food passes into the hepatic caecum, which has

been de finitely shown on embryological and physiological grounds

to be the simplest persistent form of the vertebrate liver.

Nervous System.--As has already been indicated, a solid

subcylindrical elastic rod, the notochord, surrounded by

a sheath of laminar connective tissue, the cordal sheath,

lies above the alimentary canal in contact with its dorsal

wall, and extends beyond it both in front and behind to the

obtusely pointed extremities of the body. This notochord

represents the persistent primordial skeletal axis which, in

the higher Craniata (though not so in the lower), gives way by

substitution to the segmented vertebral column. Immediately

above the notochord there lies another subcylindrical cord,

also surrounded by a sheath of connective tissue. This

cord is neither elastic nor solid, but consists of nerve

tissue, fibres and ganglion cells, surrounding a small central

canal. For the sake of uniformity in nomenclature this

nerve-cord may be called the neurochord. It is the central

nervous system, and contains within itself the elements of

the brain and spinal marrow of higher forms. The neurochord

tapers towards its posterior end, where it is coextensive

with the notochord, but ends abruptly in front, some distance

behind the tip of the snout. The neurochord attains its

greatest thickness not at its anterior end but some way behind

this region; but the central canal dilates at the anterior

extremity to form a thin-walled cerebral vesicle, in the

front wall of which there is an aggregation of dark pigment

cells constituting an eyespot, visible through the transparent

skin (fig. 1). There are two pairs of specialized cerebral

nerves innervating the praeoral lobe, and provided with

peripheral ganglia placed near the termination of the smaller

branches. Corresponding with each pair of myotomes, and

subject to the same alternation, two pairs of spinal nerves

arise from the neurochord, namely, a right and left pair of

compact dorsal sensory roots without ganglionic enlargement,

and a right and left pair of ventral motor roots composed of

loose fibres issuing separately from the neurochord and passing

directly to their termination on the muscle-plates of the

myotomes. The first dorsal spinal nerve coincides in position

with the myocomma which separates the first myotome from the

second on each side, and thereafter the successive dorsal

roots pass through the substance of the myocommata on their

way to the skin; they are therefore septal or intersegmental in

position. The ventral roots, on the contrary, are myal or

segmental in position. In addition to the cerebral eyespot

there are large numbers of minute black pigmented bodies beside

and below the central canal of the neurochord, commencing

from the level of the third myotome. It has been determined

that these bodies are of the nature of eyes (Becheraugen, R.

Hesse), each consisting of two cells, a cup-shaped pigment

cell and a triangular retinal cell. These may be called the

spinal eyes, and it is said that they are disposed in such

a way as to receive illumination preferentially from the

right side, although this fact has no relation with the side

upon which Amphioxus may lie upon the sand. When kept in

captivity the animal often lies upon one side on the surface

of the sand, but on either side indifferently. Over the

cerebral eye there is a small orifice placed to the left of

the base of the cephalic fin, leading into a pit which extends

from the surface of the body to the surface of the cerebral

vesicle; this is known as A. von Kolliker's olfactory pit.

Reproductive System.--The sexes are separate, and the male or female

Fig. 5.--Diagram of embryo gonads, or Amphioxus seen from above

in optical section. (Adapted from Hatschek.) pc, Praechordal

head-cavity of embryo; cc, collar-cavity (first somite); my,

mesodermic somites (myocoelomic or archenteric pouches); ch,

notochord with the neural tube (neurochord) lying upon it; np,

anterior neuropore; ne, position of posterior neurenteric canal.

gonads, which are exactly similar in outward appearance, occur

as a series of gonadic pouches projecting into the atrial cavity

at the base of the myotomes (figs. 2, 3, 4). At the breeding

season the walls of the pouches burst and the sexual elements

pass into the atrium, whence they are discharged through the

atriopore into the water, where fertilization takes place.

Development.--The development of Amphioxus possesses many

features of interest, and cannot fail to retain its importance

as an introduction to the study of embryology. The four

principal phases in the development are: (1) Blastula, (2)

Gastrula, (3) Flagellate Embryo, (4) Larva. The segmentation

or cleavage of the ovum which follows upon fertilization

terminates in the achievement of the blastula form, a minute

sphere of cells surrounding a central cavity. Then follows

the phenomenon of gastrulation, by which one-half of the

blastula is invaginated into the other, so as to obliterate

the segmentation cavity. The embryo now consists of two

layers of cells, epiblast and hypoblast, surrounding a cavity,

the archenteron, which opens to the exterior by the orifice

of invagination or blastopore. One important fact should

FIG. 6.--Anterior region of two pelagic larvae of A.

lanceolatus obtained by the tow-net in 8-10 fathoms, showing

the asymmetry of the large lateral sinistral mouth with its

ciliated margin cm and the dextral series of simple primary

gill-slits (1ps-14ps.) The larvae swim normally like the

adult or suspend themselves by their flagella (not shown in

the figures) vertically in mid-water. There is nothing in

their mode of life which will afford an explanation of the

asymmetry which is a developmental phenomenon. Lettering of

upper figure.--anp, Anterior neural pore; bc, rudiment

of buccal skeleton; c, cilia; cb, ciliated band; cc,

ciliated groove; cm, cilia at margin of mouth; gl, external

opening of club-shaped gland; Hn, Hatschek's nephridium;

lm, left metapleur; n, notochord; pp, praeoral pit;

ps, primary gill-slits, 1, 5, and 13; rm, right metapleur

showing through. Lettering of'lower fgure.--a, Atrium;

al, alimentary canal; bp, blood-vessel; cv, cerebral

vesicle; df, dorsal section of myocoel (=fin spaces); e,

``eyespot''; end, endostyle; gl, club-shaped gland; lm,

edge of left metapleur; m, lower edge of mouth; n, notochord;

nt} pigmented nerve tube; ps, primary gill-slits, 1, 9,

and 14; rc, renal cells on atrial floor; rm, edge of right

metapleur; so, sense organ opening into praeoral pit; ss,

thickenings, the rudiments of the row of secondary gill-slits.

be noted with regard to the gastrula, in which it seems to

differ from the gastrulae of invertebrata. After invagination

is completed, the embryo begins to elongate, the blastopore

becomes narrower, and the dorsal wall of the gastrula loses its

convexity, and becomes flattened to form the dorsal plate,

the outer layer of which is the primordium of the neurochord

and the inner layer the primordium of the notochord. While

still within the egg-membrane the epiblastic cells become

flagellated, and the gastrula rotates within the membrane.

About the eighth hour after commencement of development the

membrane ruptures and the oval embryo escapes, swimming by

means of its flagella at the surface of the sea for another

twenty-four hours, during which the principal organs are laid

down, although the mouth does not open until the close of this

period. The primordium of the neurochord (neural or medullary

plate) referred to above becomes closed in from the surface by

the overgrowth of surrounding epiblast, and its edges also bend

up, meet, and finally fuse to form a tube, the medullary or neural

tube. An important fact to note is that the blastopore is

included in this overgrowth of epiblast, so that the neural

tube remains for some time in open communication with the

archenteron by means of a posterior neurenteric canal. It is

still longer before the neural tube completes its closure in

front, exhibiting a small orifice at the surface, the anterior

neuropore. It is thus possible that the neurenteric canal

is due to the conjunction of a posterior neuropore with

the blastopore, i.e. it is a complex and not a simple

structure. Paired archenteric pouches meanwhile appear at

the sides of the axial notochordal tract, the mesoblastic

somites. The first of these differs in several respects from

those which succeed, and has been called the collar cavity

(MacBride). In front of the latter there remains a portion

of the archenteron, which becomes constricted off as the head

cavity. This becomes divided into two, the right half

forming the cavity of the rostrum, while the left acquires

an opening to the exterior, and forms the praeoral pit

of the larva, which subsequently gives rise to special

ciliated tracts in the vestibule of the mouth mentioned

above. The larval period commences at about the thirty-sixth

hour with the perforation of the mouth, first gill-cleft and

anus. The larva is curiously asymmetrical, as many as

fourteen gill-clefts appearing in an unpaired series on the

right side, while the mouth is a large orifice on the left

side, the anus being median. The adult form is achieved by

metamorphosis, which cannot be further described here.

One point must not be omitted, namely, the homogeny of the

endostyle of Amphioxus and the thyroid gland of Craniata.

REFERENCES.--T. Boveri, ``Die Nierencanalchen des

Amphioxus,'' Zool Jahrb. Anat. v. (1892), p. 429; T. Felix,

``Beitrage zur Entwickelungsgeschichte der Salmoniden,''

Anat. Hefte Arb. viii. 1897; Amphioxus, p. 333; T.

Garbowski, ``Amphioxus als Grundlage der Mesodermtheorie,''

Anat Anz. xiv. (1898), p. 473; R. Hesse, ``Die Sehorgane

des Amphioxus,'' Zeitschr. wiss. Zool. lxiii. (1898), p

456; J. W. Kirkaldy, ``A Revision of the Genera and Species

of the Branchiostomidae,'' Quart. J. Micr. Sci. xxxvii.

(1895), p. 303; E. R. Lankester, ``Contributions to the

Knowledge of Amphioxus lanceolatus (Yarrell),'' op. cit.,

xxix. (1889), p. 365; Lwoff, ``Die Bildung der primaren

Keimblatter und die Entstehung der Chorda und des Mesoderms

bei den Wirbelthieren,'' Bull. Soc. Moscow (1894); E. W.

MacBride, ``The early Development of Amphioxus,'' Quart. J.

Micr. Sci. xl. (1897), p. 589, and xliii. (1900); T. H.

Morgan and A. P. Hazen, ``The Gastrulation of Amphioxus,''

J. Morphol. xvi. (1900), p. 569; P. Sammassa, ``Studien

uber den Einfluss des Dotters auf die Gastrulation und die

Bildung der primaren Keimblatter der Wirbelthiere: iv.

Amphioxus,'' Arch. f. Entwick. Mech. vii. (1898), p. 1;

G. Schneider, ``Einiges uber Resorption und Excretion bei

Amphioxus lanceolatus,'' Anat. Anz. xvi. (1899), p. 601; J.

Sobotta, ``Die Reifung und Befruchtung des Eies von Amphioxus

lanceolatus,'' Arch. mikr. Anat. l. (1897), p. 15; F. E. Weiss,

``Excretory tubules in Amphioxus lanceolatus,'' Quart. J.

Micr. Sci. xxxi. (1890), p. 489; A. Willey, Amphioxus

and the ancestry of the Vertebrates (1894); ``Remarks on

some recent Work on the Protochorda,'' Quart. J. Micr.

Sci. xliii. (1899), p. 223; pleuron of New Zealand,'' ib.

(1901); E. Burchardt, ``Finer Anatomy of Amphioxus,'' with

bibliography, Jena Zeitschr. xxxiv. (1900), p. 719. (A. W.*)

AMPHIPOLIS (mod. Yeni Keui), an ancient city of

Macedonia, on the east bank of the river Strymon, where

it emerges from Lake Cercinitis, about 3 m. from the sea.

Originally a Thracian town, known as 'Ennea `Odoi (``Nine

Roads''), it was colonized by Athenians with other Greeks

under Hagnon in 437 B.C., previous attempts--in 497, 476

(Schol. Aesch. De fals. leg. 31) and 465--having been

unsuccessful. In 424 B.C. it surrendered to the Spartan

Brasidas without resistance, owing to the gross negligence

of the historian Thucydides, who was with the fleet at

Thasos. In 422 B.C. Cleon led an unsuccessful expedition

to recover it, in which both he and Brasidas were slain.

The importance of Amphipolis in ancient times was due to

the fact that it commanded the bridge over the Strymon, and

consequently the route from northern Greece to the Hellespont;

it was important also as a depot for the gold and silver mines

of the district, and for timber, which was largely used in

shipbuilding. This importance is shown by the fact that, in

the peace of Nicias (421 B.C.), its restoration to Athens

is made the subject of a special provision, and that about

417, this provision not having been observed, at least one

expedition was made by Nicias with a view to its recovery.

Philip of Macedon made a special point of occupying it (357),

and under the early empire it became the headquarters of the

Roman propraetor, though it was recognized as independent. Many

inscriptions, coins, &c., have been found here, and traces of

the ancient fortifications and of a Roman aqueduct are visible.

AMPHIPROSTYLE (from the Gr. amfi, on both sides,

and prostulos, a portico), the term for a temple

(q.v.) with a portico both in the front and in the rear.

AMPHISBAENA (a Greek word, from amfis, both ways, and

bainein, to go), a serpent in ancient mythology, beginning

or ending at both head and tail alike. Its fabled existence

has been utilized by the poets, such as Milton, Pope and

Tennyson. In modern zoology it is the name given to the

main genus of a family of worm-shaped lizards, most of which

inhabit the tropical parts of America, the West Indies and

Africa. The commonest species in South America and the

Antilles is the sooty or dusky A. fuliginosa. The body of

the amphisbaena, from 18 to 20 in. long, is of nearly the

same thickness throughout. The head is small, and there can

scarcely be said to be a tail, the vent being close to the

extremity of the body. The animal lives mostly underground,

burrowing in soft earth, and feeds on ants and other small

animals. From its appearance, and the ease with which it

moves backwards, has arisen the popular belief that the

amphisbaena has two heads, and that when the body is cut in

two the parts seek each other out and reunite. From this has

arisen another popular error, which attributes extraordinary

curative properties to its flesh when dried and pulverized.

AMPHITHEATRE (Gr. amfi, around, and theatron, a

place for spectators), a building in which the seats for

spectators surround the scene of the performance. The

word was doubtless coined by the Greeks of Campania, since

it was here that the gladiatorial shows for which the

amphitheatre was primarily used were first organized as public

spectacles. The earliest building of the kind still extant

is that at Pompeii, built after 80 B.C. It is called

spectacula in a contemporary inscription. The word

amphitheatrum is first found in writers of the Augustan age.

In Italy, combats of gladiators at first took place in the

forums, where temporary wooden scaffoldings were erected for

the spectators; and Vitruvius gives this as the reason why in

that country the forums were in the shape of a parallelogram

instead of being squares as in Greece. Wild beasts were

also hunted in the circus. But towards the end of the Roman

republic, when the shows increased both in frequency and in

costliness, special buildings began to be provided for them.

The first amphitheatre at Rome was that constructed, 59 B.C.,

by C. Scribonius Curio. Pliny tells us that Curio built two

wooden theatres, which were placed back to back, and that after

the dramatic representations were finished, they were turned

round, with all the spectators in them, so as to make one

circular theatre, in the centre of which gladiators fought;

but the story is incredible, and must have arisen from the

false translation of amfitheatron by ``double theatre.''

It is uncertain whether Caesar, in 46 B.C., constructed a

temporary amphitheatre of wood for his shows of wild beasts;

at any rate, the first permanent amphitheatre was built by

C. Statilius Taurus in 20 B.C. Probably the shell only

was of stone. It was burnt in the great fire of A.D. 64.

We hear of an amphitheatre begun by Caligula and of a wooden

structure raised in the year A.D. 57 by Nero; but these

were superseded by the Amphitheatrum Flavium (known at

least since the 8th century as the Colosseum, from its

colossal size), which was begun by Vespasian on the site of

an artificial lake included in the Golden House of Nero, and

inaugurated by Titus in A.D. 80 with shows lasting one hundred

days. It was several times restored by the emperors, having

been twice struck by lightning in the 3rd century and twice

damaged by earthquake in the 5th. Gladiatorial shows were

suppressed by Honorius in A.D. 404, and wild beast shows

are not recorded after the reign of Theodoric (d. A.D.

526). In the 8th century Bede wrote Quamdiu stabit Coliseus,

stabit et Roma; quando cadet Coliseus, cadet et Roma. A

large part of the western arcades seem to have collapsed in the

earthquake of A.D. 1349, and their remains were used in the

Renaissance as a quarry for building materials (e.g. for the

Palazzo di Venezia, the Cancelleria and the Palazzo Farnese).

Rome possesses the remains of a second amphitheatre on the

Esquiline, called by the chronologist of A.D. 354 Amphitheatrum

Castrense, which probably means the ``court'' or ``imperial''

amphitheatre. Its fine brickwork seems to date from Trajan's

reign. It was included by Aurelian in the circuit of his

wall. The remains of numerous amphitheatres exist in the

various provinces of the empire. The finest are--in Italy,

those of Verona (probably of the Flavian period), Capua (built

under Hadrian) and Pozzuoli; in France, at Nimes, Arles and

Frejus; in Spain, at Italica (near Seville); in Tunisia, at

Thysdrus (El-Jem); and at Pola, in Dalmatia. The builders

often took advantage of natural features, such as a depression

between hills; and ruder structures, mainly consisting of

banked-up earth, are found, e.g. at Silchester (Calleva).

The amphitheatre at Pompeii (length 444ft., breadth 342 ft.,

seating capacity 20,000) is formed by a huge embankment of

earth supported by a retaining wall and high buttresses carrying

arches. The stone seats (of which there are thirty-five rows

in three divisions) were only gradually constructed as the

means of the community allowed. Access to the highest seats

was given by external staircases, and there was no system

of underground chambers for wild beasts, combatants, &c.

In contrast to this simple structure the Colosseum represents

the most elaborate type of amphitheatre created by the architects

of the empire. Its external elevation consisted of four

storeys. The three lowest had arcades whose piers were

adorned with engaged columns of the three Greek orders. The

arches numbered eighty. Those of the basement storey served

as entrances; seventy-six were numbered and allotted to the

general body of spectators, those at the extremities of the

major axis led into the arena, and the boxes reserved for

the emperor and the presiding magistrate were approached from

the extremities of the minor axis. The higher arcades had a

low parapet with (apparently) a statue in each arch, and gave

light and air to the passages which surrounded the building.

The openings of the arcades above the principal entrances

were larger than the rest, and were adorned with figures of

chariots. The highest stage was composed of a continuous

wall of masonry, pierced by forty small square windows, and

adorned with Corinthian pilasters. There was also a series of

brackets to support the poles on which the awning was stretched.

The interior may be naturally divided into the arena and the cavea

(see annexed plan, which shows the Colosseum at two different levels).

The arena was the portion assigned to the combatants,

and derived its name from the sand with which it was

strewn, to absorb the blood and prevent it from becoming

slippery. Some of the emperors showed their prodigality

by substituting precious powders, and even gold dust, for

sand. The arena was generally of the same shape as the

amphitheatre itself, and was separated from the spectators

by a wall built perfectly smooth, that the wild beasts might

not by any possibility climb it. At Rome it was faced inside

with polished marble, but at Pompeii it was simply painted.

For further security, it was surrounded by a metal railing or

network, and the arena was sometimes surrounded also by a ditch

(euripus), especially on account of the elephants. Below

the arena were subterranean chambers and passages, from which

wild beasts and gladiators were raised on movable platforms

(pegmata) through trap-doors. Such chambers have been found

in the amphitheatres of Capua and Pozzuoli as well as in the

Colosseum. Means were also provided by which the arena could

be flooded when a sea-fight (naumachia) was exhibited,

as was done by Titus at the inauguration of the Colosseum.

The part assigned to the spectators was called cavea. It was

divided into several galleries (maeniana) concentric with

the outer walls, and therefore, like them, of an elliptical

form. The place of honour was the lowest of these, nearest to

the arena, and called the podium. The divisions in it were

larger, so as to be able to contain movable seats. At Rome

it was here that the emperor sat, his box bearing the name of

suggestus, cubiculum or pulvinar. The senators, principal

magistrates, vestal virgins, the provider (editor) of the

show, and other persons of note, occupied the rest of the

podium. At Nimes, besides the high officials of the town,

the podium had places assigned to the principal gilds,

whose names are still seen inscribed upon it, with the number

of places reserved for each. In the Colosseum there were

three maeniana above the podium, separated from each

other by terraces (praecinctiones) and walls (baltei),

and divided vertically into wedge-shaped blocks (cunei) by

stairs. The lowest was appropriated to the equestrian

order, the highest was covered in with a portico, whose

roof formed a terrace on which spectators found standing

room. Numerous passages (vomitoria) and small stairs

gave access to them; while long covered corridors, behind

and below them, served for shelter in the event of rain.

At Pompeii each place was numbered, and elsewhere their

extent is defined by little marks cut in the stone. The

spectators were admitted by tickets (tesserae), and order

preserved by a staff of officers appointed for the purpose.

The height of the Colosseum is about 160 ft.; but the fourth

storey in its present form is not earlier in date than the

3rd century A.D. It seems to have been originally of wood,

since an inscription of the year A.D. 80 mentions the summum

maenianum in ligneis. It is stated in the Notitia Urbis

Romae (4th century) that the Colosseum contained 87,000

places; but Huelsen calculates that the seats would accommodate

45,000 persons at most, besides whom 5000 could find standing

room. The exaggerated estimate is due to the fact that

space was allotted to corporate bodies, whose numbers were

taken as data. The greatest length is about 615 ft., and

the length of the shorter axis of the ellipse about 510

ft. The dimensions of the arena were 281 ft. by 177 ft.

The following table, giving the dimensions of some

of the principal amphitheatres, is based mainly

on the figures given by Friedlander (l.c.):--

|----------------------|---------------------|--------------------|

| | ENTIRE BUILDING. | ARENA. |

| |---------|-----------|----------|---------|

| | Greater | Shorter | Greater | Shorter |

| | Axis. | Axis. | Axis. | Axis. |

| |---------|-----------|----------|---------|

| Rome (Colosseum) | 615 | 510 1/2 | 281 | 177 |

| Capua | 557 | 458 | 250 | 148 |

| Julia Caesarea | 551 | 289 | 459 | 197 |

|Italica (Seville) | 514 | 439 1/2 | . . | . . |

| Verona | 502 1/2| 403 | 248 | 145 1/2 |

| Thysdrus | 488 | 406 | 308 | 197 |

| Tarraco | 486 | 390 | 277 | 181 |

| Pozzuoli | 482 | 383 | 236 1/2 | 137 3/4 |

| Tours | 472 | 406 | 223 | 98 1/2 |

| Pola | 449 1/2| 367 1/2 | 230 | 144 1/2 |

| Arles | 448 | 352 | 229 | 129 |

| Pompeii | 444 | 342 | 218 1/2 | 115 |

| Nimes | 440 | 336 | 227 | 126 1/2 |

|----------------------|---------|-----------|----------|---------|

BIBLIOGRPHY.--Arts. ``Amphitheatrum'' in Smith's Dictionary

of Greek and Roman Antiquities (3rd ed., 1890), and in Daremberg

and Saglio's Dictionnaire des antiquites; Friedlander,

Darstellungen aus der Sittengeschichte Roms (6th ed., 1888-1890),

vol. ii. pp. 551-620; Durm, Geschichte der Baukunst, II.2

(1905), 360 ff. Of older works, J. Lipsius, De Amphitheatris

(1585): Carlo Fontana, L'Anfiteatro Flavio (1725); and

Maffei, Verona Illustrata, vol. ii. (1826), are worthy of

mention. For the amphitheatre at Pompeii, see Mau-Kelsey.

Pompeii, its Life and Art (2nd ed. 1904), chap. 30; for

the Colosseum, Middleton, Remains of Ancient Rome, ii.

pp. 78-110, and Huelsen's art. ``Flavium Amphitheatrum''

in Pauly-Wossowa, Realencyclopadie. (H. S. J.)

AMPHITRITE, in ancient Greek mythology, a sea-goddess,

daughter of Nereus (or Oceanus) and wife of Poseidon. She

was so entirely confined in her authority to the sea and

the creatures in it, that she was never associated with

her husband either for purposes of worship or in works of

art, except when he was to be distinctly regarded as the

god who controlled the sea. She was one of the Nereids,

and distinguishable from the others only by her queenly

attributes. It was said that Poseidon saw her first dancing

at Naxos among the other Noreids, and carried her off (Schol.

on Od. iii. 91). But in another version of the myth, she

then fled from him to the farthest ends of the sea, where

the dolphin of Poseidon found her, and was rewarded by being

placed among the stars (Eratosthenes, Catast. 31). In works

of art she is represented either enthroned beside him, or

driving with him in a chariot drawn by sea-horses or other

fabulous creatures of the deep, and attended by Tritons and

Nereids. In poetry her name is often used for the sea.

AMPHITRYON, in Greek mythology, son of Alcaeus, king of

Tiryns in Argolis. Having accidentally killed his uncle

Electryon, king of Mycenae, he was driven out by another uncle,

Sthenelus. He fled with Alcmene, Electryon's daughter, to

Thebes, where he was cleansed from the guilt of blood by

Creon, his maternal uncle, king of Thebes. Alcmene, who

had been betrothed to Amphitryon by her father, refused to

marry him until he had avenged the death of her brothers,

all of whom except one had fallen in battle against the

Taphians. It was on his return from this expedition that

Electryon had been killed. Amphitryon accordingly took the

field against the Taphians, accompanied by Creon, who had

agreed to assist him on condition that he slew the Teumessian

fox which had been sent by Dionysus to ravage the country.

The Taphians, however, remained invincible until Comaetho,

the king's daughter, out of love for Amphitryon cut off her

father's golden hair, the possession of which rendered him

immortal. Having defeated the enemy, Amphitryon put Comaetho

to death and handed over the kingdom of the Taphians to

Cephalus. On his return to Thebes he married Alcmene, who

gave birth to twin sons, Iphicles being the son of Amphitryon,

Heracles of Zeus, who had visited her during Amphitryon's

absence. He fell in battle against the Minyans, against

whom he had undertaken an expedition, accompanied by the

youthful Heracles, to deliver Thebes from a disgraceful

tribute. According to Euripides (Hercules Furens) he

survived this expedition, and was slain by his son in his

madness. Amphitryon was the title of a lost tragedy of

Sophocles; the episode of Zeus and Alcmene forms the subject

of comedies by Plautus and Moliere. From Moliere's line

``Le veritable Amphitryon est l'Amphitryon ou l'on dine''

(Amphitryon, iii. 5), the name Amphitryon has come to be

used in the sense of a generous entertainer, a good host.

Apollodorus ii. 4; Herodotus v. 59; Pausanias viii. 14, ix,

10, 11, 17; Hesiod, Shield, 1-56; Pindar, Pythia, ix. 81.

AMPHORA (a Latin word from Gr. amforeus, derived from

amfi, on both sides, and ferein, to bear), a large

big-bellied vessel used by the ancient Greeks and Romans for

preserving wine, oil, honey, and fruits; and in later times

as a cinerary urn. It was so named from usually having an

ear or handle on each side of the neck (diota.) It was

commonly made of earthenware, but sometimes of stone, glass

or even more costly materials. Amphorae either rested on a

foot, or ended in a point so that they had to be fixed in the

ground. The older amphorae were oval-shaped, such as the vases

filled with oil for prizes at the Panathenaic festival, having

on one side a figure of Athena, on the other a representation

of the contest; the latter were tall and slender, with voluted

handles. The first class exhibits black figures on a reddish

background, the second red figures on a black ground. The

amphora was a standard measure of capacity among both Greeks

and Romans, the Attic containing nearly nine gallons, and

the Roman about six. In modern botany it is a technical

term sometimes denoting the lower part of the capsule called

pyxidium, attached to the flower stalk in the form of an urn.

AMPLIATIVE (from Lat. ampliare, to enlarge), an adjective

used mainly in logic, meaning ``extending,' or ``adding to that

which is already known.'' In Norman law an ``ampliation'' was a

postponement of a sentence in order to obtain further evidence.

AMPLITUDE (from Lat. amplus, large), in astronomy, the

angular distance of the rising or setting sun, or other heavenly

body, from the east or west point of the horizon; used mostly

by navigators in finding the variation of the compass by the

setting sun. In algebra, if a be a real positive quantity

and o a root of unity, then a is the amplitude of the

product ao. In elliptic integrals, the amplitude is

the limit of integration when the integral is expressed in

the form $\int_0^\phi\sqrt{1-N^2\sin^2\phi}d\phi$. The

hyperbolic or Gudermannian amplitude of the quantity

x is tan-1 (sinh x.) In mechanics, the amplitude

of a wave is the maximum ordinate. (See WAVE.)

AMPSANCTUS, or AMSANCTUS (mod. Sorgente Mefita), a

small lake in the territory of the Hirpini, IO m. S.E.

of Aeclanum, close to the Via Appia. There are now two

small pools which exhale carbonic acid gas and sulphuretted

hydrogen. Close by was a temple of the goddess Mephitis,

with a cave from which suffocating vapours rose, and for

this reason the place was brought into connexion with the

legends of the infernal regions. Virgil's description

(Aeneid, vii. 563) is not, however, very accurate.

AMPTHILL, ODO WILLIAM LEOPOLD RUSSELL, 1ST BARON (1829-1884),

British diplomatist and ambassador, was born in Florence on

the 20th of February 1829. He was the son of Major- General

Lord George William Russell, by Elizabeth Ann, niece of the

marquess of Hastings, who was governor-general of India during

the final struggle with the Mahrattas. His education, like

that of his two brothers--Hastings, who became eventually

9th duke of Bedford, and Arthur, who sat for a generation in

the House of Commons as member for Tavistock--was carried on

entirely at home, under the general direction of his mother,

whose beauty was celebrated by Byron in Beppo. Lady William

Russell was as strong-willed as she was beautiful, and certainly

deserved to be described as she was by Disraeli, who said in

conversation, ``I think she is the most fortunate woman in

England, for she has the three nicest sons.'' If it had not

been for her strong will it is as likely as not that all

the three would have gone through the usual mill of a public

school, and have lost half their very peculiar charm. In

March 1849 Odo was appointed by Lord Malmesbury attache at

Vienna. From 1850 to 1852 he was temporarily employed in the

foreign office, whence he passed to Paris. He remained there,

however, only about two months, when he was transferred to

Vienna. In 1853 he became second paid attache at Paris,

and in August 1854 he was transferred as first paid attache

to Constantinople, where he served under Lord Stratford de

Redcliffe. He had charge of the embassy during his chief's

two visits to the Crimea in 1855, but left the East to work

under Lord Napier at Washington in 1857. In the following

year he became secretary of legation at Florence, but was

detached from that place to reside in Rome, where he remained

for twelve years, till August 1870. During all that period

he was the real though unofficial representative of England

at the Vatican, and his consummate tact enabled him to do

all, and more than all, that an ordinary man could have

done in a stronger position. A reference, however, to his

evidence before a committee of the House of Commons in 1871

will make it clear to any unprejudiced reader that those were

right who, during the early 'fifties, urged so strongly the

importance of having a duly accredited agent at the papal

court. The line taken by him during the Vatican council

has been criticized, but no fault can justly be found with

it. Abreast as he was of the best thought of his time--the

brother of Arthur Russell, who, more perhaps than any other

man, was its most ideal representative in London society--he

sympathized strongly with the views of those who laboured

to prevent the extreme partisans of papal infallibility from

having everything their own way. But in his capacity of

clear-headed observer, whose business it was to reflect the

actual truth upon the mind of his government, he was obliged

to make it quite clear that they had no chance whatever,

and in conversing with those whose opinions were quite

unlike his own, such as Cardinal Manning, he seems to have

shown that he had no illusions about the result of the long

debate. In 1868 Odo Russell married Lady Emily Theresa

Villiers, the daughter of Lord Clarendon. In 1870 he was

appointed assistant under-secretary at the foreign office, and

in November of that year was sent on a special mission to the

headquarters of the German army, where he remained till 1871.