FOOTNOTE:

[1] The word is probably derived from an Indo-European root, meaning

"youthful," found in Latin, Greek, English and Sanskrit. Some have

suggested that the first two letters are from [Greek: uein], to rain,

(cf. Hyades).

HYADES ("the rainy ones"), in Greek mythology, the daughters of Atlas

and Aethra; their number varies between two and seven. As a reward for

having brought up Zeus at Dodona and taken care of the infant Dionysus

Hyes, whom they conveyed to Ino (sister of his mother Semele) at Thebes

when his life was threatened by Lycurgus, they were translated to heaven

and placed among the stars (Hyginus, _Poët. astron._ ii. 21). Another

form of the story combines them with the Pleiades. According to this

they were twelve (or fifteen) sisters, whose brother Hyas was killed by

a snake while hunting in Libya (Ovid, _Fasti_, v. 165; Hyginus, _Fab._

192). They lamented him so bitterly that Zeus, out of compassion,

changed them into stars--five into the Hyades, at the head of the

constellation of the Bull, the remainder into the Pleiades. Their name

is derived from the fact that the rainy season commenced when they rose

at the same time as the sun (May 7-21); the original conception of them

is that of the fertilizing principle of moisture. The Romans derived the

name from [Greek: us] (pig), and translated it by _Suculae_ (Cicero, _De

nat. deorum_, ii. 43).

HYATT, ALPHEUS (1838-1902), American naturalist, was born at Washington,

D.C., on the 5th of April 1838. From 1858 to 1862 he studied at Harvard,

where he had Louis Agassiz for his master, and in 1863 he served as a

volunteer in the Civil War, attaining the rank of captain. In 1867 he

was appointed curator of the Essex Institute at Salem, and in 1870

became professor of zoology and palaeontology at the Massachusetts

Institute of Technology (resigned 1888), and custodian of the Boston

Society of Natural History (curator in 1881). In 1886 he was appointed

assistant for palaeontology in the Cambridge museum of comparative

anatomy, and in 1889 was attached to the United States Geological Survey

as palaeontologist for the Trias and Jura. He was the chief founder of

the American Society of Naturalists, of which he acted as first

president in 1883, and he also took a leading part in establishing the

marine biological laboratories at Annisquam and Woods Hole, Mass. He

died at Cambridge on the 15th of January 1902.

His works include _Observations on Fresh-water Polyzoa_ (1866);

_Fossil Cephalopods of the Museum of Comparative Zoology_ (1872);

_Revision of North American Porifera_ (1875-1877); _Genera of Fossil

Cephalopoda_ (1883); _Larval Theory of the Origin of Cellular Tissue_

(1884); _Genesis of the Arietidae_ (1889); and _Phylogeny of an

acquired characteristic_ (1894). He wrote the section on Cephalopoda

in Karl von Zittel's _Paläontologie_ (1900), and his well-known study

on the fossil pond snails of Steinheim ("The Genesis of the Tertiary

Species of Planorbis at Steinheim") appeared in the _Memoirs_ of the

Boston Natural History Society in 1880. He was one of the founders and

editors of the _American Naturalist_.

HYBLA, the name of several cities In Sicily. The best known

historically, though its exact site is uncertain, is Hybla Major, near

(or by some supposed to be identical with) Megara Hyblaea (q.v.):

another Hybla, known as Hybla Minor or Galeatis, is represented by the

modern Paternò; while the site of Hybla Heraea is to be sought near

Ragusa.

HYBRIDISM. The Latin word _hybrida_, _hibrida_ or _ibrida_ has been

assumed to be derived from the Greek [Greek: hybris], an insult or

outrage, and a hybrid or mongrel has been supposed to be an outrage on

nature, an unnatural product. As a general rule animals and plants

belonging to distinct species do not produce offspring when crossed with

each other, and the term hybrid has been employed for the result of a

fertile cross between individuals of different species, the word mongrel

for the more common result of the crossing of distinct varieties. A

closer scrutiny of the facts, however, makes the term hybridism less

isolated and more vague. The words species and genus, and still more

subspecies and variety, do not correspond with clearly marked and

sharply defined zoological categories, and no exact line can be drawn

between the various kinds of crossings from those between individuals

apparently identical to those belonging to genera universally recognized

as distinct. Hybridism therefore grades into mongrelism, mongrelism into

cross-breeding, and cross-breeding into normal pairing, and we can say

little more than that the success of the union is the more unlikely or

more unnatural the further apart the parents are in natural affinity.

The interest in hybridism was for a long time chiefly of a practical

nature, and was due to the fact that hybrids are often found to present

characters somewhat different from those of either parent. The leading

facts have been known in the case of the horse and ass from time

immemorial. The earliest recorded observation of a hybrid plant is by J.

G. Gmelin towards the end of the 17th century; the next is that of Thomas

Fairchild, who in the second decade of the 18th century, produced the

cross which is still grown in gardens under the name of "Fairchild's

Sweet William." Linnaeus made many experiments in the cross-fertilization

of plants and produced several hybrids, but Joseph Gottlieb Kölreuter

(1733-1806) laid the first real foundation of our scientific knowledge of

the subject. Later on Thomas Andrew Knight, a celebrated English

horticulturist, devoted much successful labour to the improvement of

fruit trees and vegetables by crossing. In the second quarter of the 19th

century C. F. Gärtner made and published the results of a number of

experiments that had not been equalled by any earlier worker. Next came

Charles Darwin, who first in the _Origin of Species_, and later in _Cross

and Self-Fertilization of Plants_, subjected the whole question to a

critical examination, reviewed the known facts and added many to them.

Darwin's conclusions were summed up by G. J. Romanes in the 9th

edition of this _Encyclopaedia_ as follows:--

1. The laws governing the production of hybrids are identical, or

nearly identical, in the animal and vegetable kingdoms.

2. The sterility which so generally attends the crossing of two

specific forms is to be distinguished as of two kinds, which, although

often confounded by naturalists, are in reality quite distinct.

For the sterility may obtain between the two parent species when first

crossed, or it may first assert itself in their hybrid progeny. In the

latter case the hybrids, although possibly produced without any

appearance of infertility on the part of their parent species,

nevertheless prove more or less infertile among themselves, and also

with members of either parent species.

3. The degree of both kinds of infertility varies in the case of

different species, and in that of their hybrid progeny, from absolute

sterility up to complete fertility. Thus, to take the case of plants,

"when pollen from a plant of one family is placed on the stigma of a

plant of a distinct family, it exerts no more influence than so much

inorganic dust. From this absolute zero of fertility, the pollen of

different species, applied to the stigma of some one species of the

same genus, yields a perfect gradation in the number of seeds

produced, up to nearly complete, or even quite complete, fertility;

so, in hybrids themselves, there are some which never have produced,

and probably never would produce, even with the pollen of the pure

parents, a single fertile seed; but in some of these cases a first

trace of fertility may be detected, by the pollen of one of the pure

parent species causing the flower of the hybrid to wither earlier than

it otherwise would have done; and the early withering of the flower is

well known to be a sign of incipient fertilization. From this extreme

degree of sterility we have self-fertilized hybrids producing a

greater and greater number of seeds up to perfect fertility."

4. Although there is, as a rule, a certain parallelism, there is no

fixed relation between the degree of sterility manifested by the

parent species when crossed and that which is manifested by their

hybrid progeny. There are many cases in which two pure species can be

crossed with unusual facility, while the resulting hybrids are

remarkably sterile; and, contrariwise, there are species which can

only be crossed with extreme difficulty, though the hybrids, when

produced, are very fertile. Even within the limits of the same genus,

these two opposite cases may occur.

5. When two species are reciprocally crossed, i.e. male A with female

B, and male B with female A, the degree of sterility often differs

greatly in the two cases. The sterility of the resulting hybrids may

differ likewise.

6. The degree of sterility of first crosses and of hybrids runs, to a

certain extent, parallel with the systematic affinity of the forms

which are united. "For species belonging to distinct genera can

rarely, and those belonging to distinct families can never, be

crossed. The parallelism, however, is far from complete; for a

multitude of closely allied species will not unite, or unite with

extreme difficulty, whilst other species, widely different from each

other, can be crossed with perfect facility. Nor does the difficulty

depend on ordinary constitutional differences; for annual and

perennial plants, deciduous and evergreen trees, plants flowering at

different seasons, inhabiting different stations, and naturally living

under the most opposite climates, can often be crossed with ease. The

difficulty or facility apparently depends exclusively on the sexual

constitution of the species which are crossed, or on their sexual

elective affinity."

There are many new records as to the production of hybrids.

Horticulturists have been extremely active and successful in their

attempts to produce new flowers or new varieties of vegetables by

seminal or graft-hybrids, and any florist's catalogue or the account of

any special plant, such as is to be found in Foster-Melliar's _Book of

the Rose_, is in great part a history of successful hybridization. Much

special experimental work has been done by botanists, notably by de

Vries, to the results of whose experiments we shall recur. Experiments

show clearly that the obtaining of hybrids is in many cases merely a

matter of taking sufficient trouble, and the successful crossing of

genera is not infrequent.

Focke, for instance, cites cases where hybrids were obtained between

_Brassica_ and _Raphanus_, _Galium_ and _Asperula_, _Campanula_ and

_Phyteuma_, _Verbascum_ and _Celsia_. Among animals, new records and

new experiments are almost equally numerous. Boveri has crossed

_Echinus microtuberculatus_ with _Sphaerechinus granularis_. Thomas

Hunt Morgan even obtained hybrids between Asterias, a starfish, and

_Arbacia_, a sea-urchin, a cross as remote as would be that between a

fish and a mammal. Vernon got many hybrids by fertilizing the eggs of

_Strongylocentrotus lividus_ with the sperm of _Sphaerechinus

granularis_. Standfuss has carried on an enormous series of

experiments with Lepidopterous insects, and has obtained a very large

series of hybrids, of which he has kept careful record. Lepidopterists

generally begin to suspect that many curious forms offered by dealers

as new species are products got by crossing known species. Apellö has

succeeded with Teleostean fish; Gebhardt and others with Amphibia.

Elliot and Suchetet have studied carefully the question of

hybridization occurring normally among birds, and have got together a

very large body of evidence. Among the cases cited by Elliot the most

striking are that of the hybrid between _Colaptes cafer_ and _C.

auratus_, which occurs over a very wide area of North America and is

known as _C. hybridus_, and the hybrid between _Euplocamus lineatus_

and _E. horsfieldi_, which appears to be common in Assam. St M.

Podmore has produced successful crosses between the wood-pigeon

(_Columba palumbus_) and a domesticated variety of the rock pigeon

(_C. livia_). Among mammals noteworthy results have been obtained by

Professor Cossar Ewart, who has bred nine zebra hybrids by crossing

mares of various sizes with a zebra stallion, and who has studied in

addition three hybrids out of zebra mares, one sired by a donkey, the

others by ponies. Crosses have been made between the common rabbit

(_Lepus cuniculus_) and the guinea-pig (_Cavia cobaya_), and examples

of the results have been exhibited in the Zoological Gardens of

Sydney, New South Wales. The Carnivora generally are very easy to

hybridize, and many successful experiments have been made with animals

in captivity. Karl Hagenbeck of Hamburg has produced crosses between

the lion (_Felis leo_) and the tiger (_F. tigris_). What was probably

a "tri-hybrid" in which lion, leopard and jaguar were mingled was

exhibited by a London showman in 1908. Crosses between various species

of the smaller cats have been fertile on many occasions. The black

bear (_Ursus americanus_) and the European brown bear (_U. arctos_)

bred in the London Zoological Gardens in 1859, but the three cubs did

not reach maturity. Hybrids between the brown bear and the

grizzly-bear (_U. horribilis_) have been produced in Cologne, whilst

at Halle since 1874 a series of successful matings of polar (_U.

maritimus_) and brown bears have been made. Examples of these hybrid

bears have been exhibited by the London Zoological Society. The London

Zoological Society has also successfully mated several species of

antelopes, for instance, the water-bucks _Kobus ellipsiprymnus_ and

_K. unctuosus_, and Selous's antelope _Limnotragus selousi_ with _L.

gratus_.

The causes militating against the production of hybrids have also

received considerable attention. Delage, discussing the question, states

that there is a general proportion between sexual attraction and

zoological affinity, and in many cases hybrids are not naturally

produced simply from absence of the stimulus to sexual mating, or

because of preferential mating within the species or variety. In

addition to differences of habit, temperament, time of maturity, and so

forth, gross structural differences may make mating impossible. Thus

Escherick contends that among insects the peculiar structure of the

genital appendages makes cross-impregnation impossible, and there is

reason to believe that the specific peculiarities of the modified sexual

palps in male spiders have a similar result.

The difficulties, however, may not exist, or may be overcome by

experiment, and frequently it is only careful management that is

required to produce crossing. Thus it has been found that when the

pollen of one species does not succeed in fertilizing the ovules of

another species, yet the reciprocal cross may be successful; that is

to say, the pollen of the second species may fertilize the ovules of

the first. H. M. Vernon, working with sea-urchins, found that the

obtaining of hybrids depended on the relative maturity of the sexual

products. The difficulties in crossing apparently may extend to the

chemiotaxic processes of the actual sexual cells. Thus when the

spermatozoa of an urchin were placed in a drop of seawater containing

ripe eggs of an urchin and of a starfish, the former eggs became

surrounded by clusters of the male cells, while the latter appeared to

exert little attraction for the alien germ-cells. Finally, when the

actual impregnation of the egg is possible naturally, or has been

secured by artificial means, the development of the hybrid may stop at

an early stage. Thus hybrids between the urchin and the starfish,

animals belonging to different classes, reached only the stage of the

pluteus larva. A. D. Apellö, experimenting with Teleostean fish, found

that very often impregnation and segmentation occurred, but that the

development broke down immediately afterwards. W. Gebhardt, crossing

_Rana esculenta_ with _R. arvalis_, found that the cleavage of the

ovum was normal, but that abnormality began with the gastrula, and

that development soon stopped. In a very general fashion there appears

to be a parallel between the zoological affinity and the extent to

which the incomplete development of the hybrid proceeds.

As to the sterility of hybrids _inter se_, or with either of the parent

forms, information is still wanted. Delage, summing up the evidence in a

general way, states that mongrels are more fertile and stronger than

their parents, while hybrids are at least equally hardy but less

fertile. While many of the hybrid products of horticulturists are

certainly infertile, others appear to be indefinitely fertile.

Focke, it is true, states that the hybrids between _Primula auricula_

and _P. hirsuta_ are fertile for many generations, but not

indefinitely so; but, while this may be true for the particular case,

there seems no reason to doubt that many plant hybrids are quite

fertile. In the case of animals the evidence is rather against

fertility. Standfuss, who has made experiments lasting over many

years, and who has dealt with many genera of Lepidoptera, obtained no

fertile hybrid females, although he found that hybrid males paired

readily and successfully with pure-bred females of the parent races.

Elliot, dealing with birds, concluded that no hybrids were

fertile with one another beyond the second generation, but thought

that they were fertile with members of the parent races. Wallace, on

the other hand, cites from Quatrefages the case of hybrids between the

moths _Bombyx cynthia_ and _B. arrindia_, which were stated to be

fertile _inter se_ for eight generations. He also states that hybrids

between the sheep and goat have a limited fertility _inter se_.

Charles Darwin, however, had evidence that some hybrid pheasants were

completely fertile, and he himself interbred the progeny of crosses

between the common and Chinese geese, whilst there appears to be no

doubt as to the complete fertility of the crosses between many species

of ducks, J. L. Bonhote having interbred in various crosses for

several generations the mallard (_Anas boschas_), the Indian spot-bill

duck (_A. poecilorhyncha_), the New Zealand grey duck (_A.

superciliosa_) and the pin-tail (_Dafila acuta_). Podmore's pigeon

hybrids were fertile _inter se_, a specimen having been exhibited at

the London Zoological Gardens. The hybrids between the brown and polar

bears bred at Halle proved to be fertile, both with one of the parent

species and with one another.

Cornevin and Lesbre state that in 1873 an Arab mule was fertilized in

Africa by a stallion, and gave birth to female offspring which she

suckled. All three were brought to the Jardin d'Acclimatation in

Paris, and there the mule had a second female colt to the same father,

and subsequently two male colts in succession to an ass and to a

stallion. The female progeny were fertilized, but their offspring were

feeble and died at birth. Cossar Ewart gives an account of a recent

Indian case in which a female mule gave birth to a male colt. He

points out, however, that many mistakes have been made about the

breeding of hybrids, and is not altogether inclined to accept this

supposed case. Very little has been published with regard to the most

important question, as to the actual condition of the sexual organs

and cells in hybrids. There does not appear to be gross anatomical

defect to account for the infertility of hybrids, but microscopical

examination in a large number of cases is wanted. Cossar Ewart, to

whom indeed much of the most interesting recent work on hybrids is

due, states that in male zebra-hybrids the sexual cells were immature,

the tails of the spermatozoa being much shorter than those of the

similar cells in stallions and zebras. He adds, however, that the male

hybrids he examined were young, and might not have been sexually

mature. He examined microscopically the ovary of a female zebra-hybrid

and found one large and several small Graafian follicles, in all

respects similar to those in a normal mare or female zebra. A careful

study of the sexual organs in animal and plant hybrids is very much to

be desired, but it may be said that so far as our present knowledge

goes there is not to be expected any obvious microscopical cause of

the relative infertility of hybrids.

The relative variability of hybrids has received considerable attention

from many writers. Horticulturists, as Bateson has written, are "aware

of the great and striking variations which occur in so many orders of

plants when hybridization is effected." The phrase has been used

"breaking the constitution of a plant" to indicate the effect produced

in the offspring of a hybrid union, and the device is frequently used by

those who are seeking for novelties to introduce on the market. It may

be said generally that hybrids are variable, and that the products of

hybrids are still more variable. J. L. Bonhote found extreme variations

amongst his hybrid ducks. Y. Delage states that in reciprocal crosses

there is always a marked tendency for the offspring to resemble the male

parents; he quotes from Huxley that the mule, whose male parent is an

ass, is more like the ass, and that the hinny, whose male parent is a

horse, is more like the horse. Standfuss found among Lepidoptera that

males were produced much more often than females, and that these males

paired readily. The freshly hatched larvae closely resembled the larvae

of the female parent, but in the course of growth the resemblance to the

male increased, the extent of the final approximation to the male

depending on the relative phylogenetic age of the two parents, the

parent of the older species being prepotent. In reciprocal pairing, he

found that the male was able to transmit the characters of the parents

in a higher degree. Cossar Ewart, in relation to zebra hybrids, has

discussed the matter of resemblance to parents in very great detail, and

fuller information must be sought in his writings. He shows that the

wild parent is not necessarily prepotent, although many writers have

urged that view. He described three hybrids bred out of a zebra mare by

different horses, and found in all cases that the resemblance to the

male or horse parent was more profound. Similarly, zebra-donkey hybrids

out of zebra mares bred in France and in Australia were in characters

and disposition far more like the donkey parents. The results which he

obtained in the hybrids which he bred from a zebra stallion and

different mothers were more variable, but there was rather a balance in

favour of zebra disposition and against zebra shape and marking.

"Of the nine zebra-horse hybrids I have bred," he says, "only two in

their make and disposition take decidedly after the wild parent. As

explained fully below, all the hybrids differ profoundly in the plan

of their markings from the zebra, while in their ground colour they

take after their respective dams or the ancestors of their dams far

more than after the zebra--the hybrid out of the yellow and white

Iceland pony, e.g. instead of being light in colour, as I anticipated,

is for the most part of a dark dun colour, with but indistinct

stripes. The hoofs, mane and tail of the hybrids are at the most

intermediate, but this is perhaps partly owing to reversion towards

the ancestors of these respective dams. In their disposition and

habits they all undoubtedly agree more with the wild sire."

Ewart's experiments and his discussion of them also throw important

light on the general relation of hybrids to their parents. He found that

the coloration and pattern of his zebra hybrids resembled far more those

of the Somali or Grévy's zebra than those of their sire--a Burchell's

zebra. In a general discussion of the stripings of horses, asses and

zebras, he came to the conclusion that the Somali zebra represented the

older type, and that therefore his zebra hybrids furnished important

evidence of the effect of crossing in producing reversion to ancestral

type. The same subject has of course been discussed at length by Darwin,

in relation to the cross-breeding of varieties of pigeons; but the

modern experimentalists who are following the work of Mendel interpret

reversion differently (see MENDELISM).

_Graft-Hybridism._--It is well known that, when two varieties or allied

species are grafted together, each retains its distinctive characters.

But to this general, if not universal, rule there are on record several

alleged exceptions, in which either the scion is said to have partaken

of the qualities of the stock, the stock of the scion, or each to have

affected the other. Supposing any of these influences to have been

exerted, the resulting product would deserve to be called a

graft-hybrid. It is clearly a matter of great interest to ascertain

whether such formation of hybrids by grafting is really possible; for,

if even one instance of such formation could be unequivocally proved, it

would show that sexual and asexual reproduction are essentially

identical.

The cases of alleged graft-hybridism are exceedingly few, considering

the enormous number of grafts that are made every year by

horticulturists, and have been so made for centuries. Of these cases the

most celebrated are those of Adam's laburnum (_Cytisus Adami_) and the

bizzarria orange. Adam's laburnum is now flourishing in numerous places

throughout Europe, all the trees having been raised as cuttings from the

original graft, which was made by inserting a bud of the purple laburnum

into a stock of the yellow. M. Adam, who made the graft, has left on

record that from it there sprang the existing hybrid. There can be no

question as to the truly hybrid character of the latter--all the

peculiarities of both parent species being often blended in the same

raceme, flower or even petal; but until the experiment shall have been

successfully repeated there must always remain a strong suspicion that,

notwithstanding the assertion and doubtless the belief of M. Adam, the

hybrid arose as a cross in the ordinary way of seminal reproduction.

Similarly, the bizzarria orange, which is unquestionably a hybrid

between the bitter orange and the citron--since it presents the

remarkable spectacle of these two different fruits blended into one--is

stated by the gardener who first succeeded in producing it to have

arisen as a graft-hybrid; but here again a similar doubt, similarly due

to the need of corroboration, attaches to the statement. And the same

remark applies to the still more wonderful case of the so-called

trifacial orange, which blends three distinct kinds of fruit in one, and

which is said to have been produced by artificially splitting and

uniting the seeds taken from the three distinct species, the fruits of

which now occur blended in the triple hybrid.

The other instances of alleged graft-hybridism are too numerous to be

here noticed in detail; they refer to jessamine, ash, hazel, vine,

hyacinth, potato, beet and rose. Of these the cases of the vine, beet

and rose are the strongest as evidence of graft-hybridization, from the

fact that some of them were produced as the result of careful

experiments made by very competent experimentalists. On the whole, the

results of some of these experiments, although so few in number, must be

regarded as making out a strong case in favour of the possibility of

graft-hybridism. For it must always be remembered that, in experiments

of this kind, negative evidence, however great in amount, may be

logically dissipated by a single positive result.

_Theory of Hybridism._--Charles Darwin was interested in hybridism as an

experimental side of biology, but still more from the bearing of the

facts on the theory of the origin of species. It is obvious that

although hybridism is occasionally possible as an exception to the

general infertility of species inter se, the exception is still more

minimized when it is remembered that the hybrid progeny usually display

some degree of sterility. The main facts of hybridism appear to lend

support to the old doctrine that there are placed between all species

the barriers of mutual sterility. The argument for the fixity of species

appears still stronger when the general infertility of species crossing

is contrasted with the general fertility of the crossing of natural and

artificial varieties. Darwin himself, and afterwards G. J. Romanes,

showed, however, that the theory of natural selection did not require

the possibility of the commingling of specific types, and that there was

no reason to suppose that the mutation of species should depend upon

their mutual crossing. There existed more than enough evidence, and this

has been added to since, to show that infertility with other species is

no criterion of a species, and that there is no exact parallel between

the degree of affinity between forms and their readiness to cross. The

problem of hybridism is no more than the explanation of the generally

reduced fertility of remoter crosses as compared with the generally

increased fertility of crosses between organisms slightly different.

Darwin considered and rejected the view that the inter-sterility of

species could have been the result of natural selection.

"At one time it appeared to me probable," he wrote (_Origin of

Species_, 6th ed. p. 247), "as it has to others, that the sterility of

first crosses and of hybrids might have been slowly acquired through

the natural selection of slightly lessened degrees of fertility,

which, like any other variation, spontaneously appeared in certain

individuals of one variety when crossed with those of another variety.

For it would clearly be advantageous to two varieties or incipient

species if they could be kept from blending, on the same principle

that, when man is selecting at the same time two varieties, it is

necessary that he should keep them separate. In the first place, it

may be remarked that species inhabiting distinct regions are often

sterile when crossed; now it could clearly have been of no advantage

to such separated species to have been rendered mutually sterile and,

consequently, this could not have been effected through natural

selection; but it may perhaps be argued that, if a species were

rendered sterile with some one compatriot, sterility with other

species would follow as a necessary contingency. In the second place,

it is almost as much opposed to the theory of natural selection as to

that of special creation, that in reciprocal crosses the male element

of one form should have been rendered utterly impotent on a second

form, whilst at the same time the male element of this second form is

enabled freely to fertilize the first form; for this peculiar state of

the reproductive system could hardly have been advantageous to either

species."

Darwin came to the conclusion that the sterility of crossed species must

be due to some principle quite independent of natural selection. In his

search for such a principle he brought together much evidence as to the

instability of the reproductive system, pointing out in particular how

frequently wild animals in captivity fail to breed, whereas some

domesticated races have been so modified by confinement as to be fertile

together although they are descended from species probably mutually

infertile. He was disposed to regard the phenomena of differential

sterility as, so to speak, by-products of the process of evolution. G.

J. Romanes afterwards developed his theory of physiological selection,

in which he supposed that the appearance of differential fertility

within a species was the starting-point of new species; certain

individuals by becoming fertile only _inter se_ proceeded along lines of

modification diverging from the lines followed by other members of the

species. Physiological selection in fact would operate in the same

fashion as geographical isolation; if a portion of a species separated

on an island tends to become a new species, so also a portion separated

by infertility with the others would tend to form a new species.

According to Romanes, therefore, mutual infertility was the

starting-point, not the result, of specific modification. Romanes,

however, did not associate his interesting theory with a sufficient

number of facts, and it has left little mark on the history of the

subject. A. R. Wallace, on the other hand, has argued that sterility

between incipient species may have been increased by natural selection

in the same fashion as other favourable variations are supposed to have

been accumulated. He thought that "some slight degree of infertility was

a not infrequent accompaniment of the external differences which always

arise in a state of nature between varieties and incipient species."

Weismann concluded, from an examination of a series of plant hybrids,

that from the same cross hybrids of different character may be obtained,

but that the characters are determined at the moment of fertilization;

for he found that all the flowers on the same hybrid plant resembled one

another in the minutest details of colour and pattern. Darwin already

had pointed to the act of fertilization as the determining point, and it

is in this direction that the theory of hybridism has made the greatest

advance.

The starting-point of the modern views comes from the experiments and

conclusions on plant hybrids made by Gregor Mendel and published in

1865. It is uncertain if Darwin had paid attention to this work;

Romanes, writing in the 9th edition of this _Encyclopaedia_, cited it

without comment. First H. de Vries, then W. Bateson and a series of

observers returned to the work of Mendel (see MENDELISM), and made it

the foundation of much experimental work and still more theory. It is

still too soon to decide if the confident predictions of the Mendelians

are justified, but it seems clear that a combination of Mendel's

numerical results with Weismann's (see HEREDITY) conception of the

particulate character of the germ-plasm, or hereditary material, is at

the root of the phenomena of hybridism, and that Darwin was justified in

supposing it to lie outside the sphere of natural selection and to be a

fundamental fact of living matter.

AUTHORITIES.--Apellö, "Über einige Resultate der Kreuzbefruchtung bei

Knochenfischen," _Bergens mus. aarbog_ (1894); Bateson, "Hybridization

and Cross-breeding," _Journal of the Royal Horticultural Society_

(1900); J. L. Bonhote, "Hybrid Ducks," _Proc. Zool. Soc. of London_

(1905), p. 147; Boveri, article "Befruchtung," in _Ergebnisse der

Anatomie und Entwickelungsgeschichte von Merkel und Bonnet_, i.

385-485; Cornevin et Lesbre, "Étude sur un hybride issu d'une mule

féconde et d'un cheval," _Rev. Sci._ li. 144; Charles Darwin, _Origin

of Species_ (1859), _The Effects of Cross and Self-Fertilization in

the Vegetable Kingdom_ (1878); Delage, _La Structure du protoplasma et

les théories sur l'hérédité_ (1895, with a literature); de Vries, "The

Law of Disjunction of Hybrids," _Comptes rendus_ (1900), p. 845;

Elliot, _Hybridism_; Escherick, "Die biologische Bedeutung der

Genitalabhänge der Insecten," _Verh. z. B. Wien_, xlii. 225; Ewart,

_The Penycuik Experiments_ (1899); Focke, _Die Pflanzen-Mischlinge_

(1881); Foster-Melliar, _The Book of the Rose_ (1894); C. F. Gaertner,

various papers in _Flora_, 1828, 1831, 1832, 1833, 1836, 1847, on

"Bastard-Pflanzen"; Gebhardt, "Über die Bastardirung von _Rana

esculenta_ mit _R. arvalis_," _Inaug. Dissert._ (Breslau, 1894); G.

Mendel, "Versuche über Pflanzen-Hybriden," _Verh. Natur. Vereins in

Brünn_ (1865), pp. 1-52; Morgan, "Experimental Studies," _Anat. Anz._

(1893), p. 141; id. p. 803; G. J. Romanes, "Physiological Selection,"

_Jour. Linn. Soc._ xix. 337; H. Scherren, "Notes on Hybrid Bears,"

_Proc. Zool. Soc. of London_ (1907), p. 431; Saunders, _Proc. Roy.

Soc._ (1897), lxii. 11; Standfuss, "Études de zoologie expérimentale,"

_Arch. Sci. Nat._ vi. 495; Suchetet, "Les Oiseaux hybrides rencontrés

à l'état sauvage," _Mém. Soc. Zool._ v. 253-525, and vi. 26-45;

Vernon, "The Relation between the Hybrid and Parent Forms of Echinoid

Larvae," _Proc. Roy. Soc._ lxv. 350; Wallace, _Darwinism_ (1889);

Weismann, _The Germ-Plasm_ (1893). (P. C. M)

HYDANTOIN (glycolyl urea),

[beta] [alpha]

/ NH · CH2

C3H4N2O2 or CO < ,

\ NH · CO

[gamma]

the ureïde of glycollic acid, may be obtained by heating allantoin or

alloxan with hydriodic acid, or by heating bromacetyl urea with

alcoholic ammonia. It crystallizes in needles, melting at 216° C.

When hydrolysed with baryta water yields hydantoic (glycoluric)acid,

H2N·CO·NH·CH2·CO2H, which is readily soluble in hot water, and on

heating with hydriodic acid decomposes into ammonia, carbon dioxide and

glycocoll, CH2·NH2·CO2·H. Many substituted hydantoins are known; the

[alpha]-alkyl hydantoins are formed on fusion of aldehyde- or

ketone-cyanhydrins with urea, the [beta]-alkyl hydantoins from the

fusion of mono-alkyl glycocolls with urea, and the [gamma]-alkyl

hydantoins from the action of alkalis and alkyl iodides on the

[alpha]-compounds. [gamma]-Methyl hydantoin has been obtained as a

splitting product of caffeine (E. Fischer, _Ann._, 1882, 215, p. 253).

HYDE, the name of an English family distinguished in the 17th century.

Robert Hyde of Norbury, Cheshire, had several sons, of whom the third

was Lawrence Hyde of Gussage St Michael, Dorsetshire. Lawrence's son

Henry was father of Edward Hyde, earl of Clarendon (q.v.), whose second

son by his second wife was Lawrence, earl of Rochester (q.v.); another

son was Sir Lawrence Hyde, attorney-general to Anne of Denmark, James

I.'s consort; and a third son was Sir Nicholas Hyde (d. 1631),

chief-justice of England. Sir Nicholas entered parliament in 1601 and

soon became prominent as an opponent of the court, though he does not

appear to have distinguished himself in the law. Before long, however,

he deserted the popular party, and in 1626 he was employed by the duke

of Buckingham in his defence to impeachment by the Commons; and in the

following year he was appointed chief-justice of the king's bench, in

which office it fell to him to give judgment in the celebrated case of

Sir Thomas Darnell and others who had been committed to prison on

warrants signed by members of the privy council, which contained no

statement of the nature of the charge against the prisoners. In answer

to the writ of _habeas corpus_ the attorney-general relied on the

prerogative of the crown, supported by a precedent of Queen Elizabeth's

reign. Hyde, three other judges concurring, decided in favour of the

crown, but without going so far as to declare the right of the crown to

refuse indefinitely to show cause against the discharge of the

prisoners. In 1629 Hyde was one of the judges who condemned Eliot,

Holles and Valentine for conspiracy in parliament to resist the king's

orders; refusing to admit their plea that they could not be called upon

to answer out of parliament for acts done in parliament. Sir Nicholas

Hyde died in August 1631.

Sir Lawrence Hyde, attorney-general to Anne of Denmark, had eleven sons,

four of whom were men of some mark. Henry was an ardent royalist who

accompanied Charles II. to the continent, and returning to England was

beheaded in 1650; Alexander (1598-1667) became bishop of Salisbury in

1665; Edward (1607-1659) was a royalist divine who was nominated dean of

Windsor in 1658, but died before taking up the appointment, and who was

the author of many controversial works in Anglican theology; and Robert

(1595-1665) became recorder of Salisbury and represented that borough in

the Long Parliament, in which he professed royalist principles, voting

against the attainder of Strafford. Having been imprisoned and deprived

of his recordership by the parliament in 1645/6, Robert Hyde gave refuge

to Charles II. on his flight from Worcester in 1651, and on the

Restoration he was knighted and made a judge of the common pleas. He

died in 1665. Henry Hyde (1672-1753), only son of Lawrence, earl of

Rochester, became 4th earl of Clarendon and 2nd earl of Rochester, both

of which titles became extinct at his death. He was in no way

distinguished, but his wife Jane Hyde, countess of Clarendon and

Rochester (d. 1725), was a famous beauty celebrated by the homage of

Swift, Prior and Pope, and by the groundless scandal of Lady Mary

Wortley Montagu. Two of her daughters, Jane, countess of Essex, and

Catherine, duchess of Queensberry, were also famous beauties of the

reign of Queen Anne. Her son, Henry Hyde (1710-1753), known as Viscount

Cornbury, was a Tory and Jacobite member of parliament, and an intimate

friend of Bolingbroke, who addressed to him his _Letters on the Study

and Use of History_, and _On the Spirit of Patriotism_. In 1750 Lord

Cornbury was created Baron Hyde of Hindon, but, as he predeceased his

father, this title reverted to the latter and became extinct at his

death. Lord Cornbury was celebrated as a wit and a conversationalist.

By his will he bequeathed the papers of his great-grandfather, Lord

Clarendon, the historian, to the Bodleian Library at Oxford.

See Lord Clarendon, _The Life of Edward, Earl of Clarendon_ (3 vols.,

Oxford, 1827); Edward Foss, _The Judges of England_ (London,

1848-1864); Anthony à Wood, _Athenae oxonienses_ (London, 1813-1820);

Samuel Pepys, _Diary and Correspondence_, edited by Lord Braybrooke (4

vols., London, 1854).

HYDE, THOMAS (1636-1703), English Orientalist, was born at Billingsley,

near Bridgnorth, in Shropshire, on the 29th of June 1636. He inherited

his taste for linguistic studies, and received his first lessons in some

of the Eastern tongues, from his father, who was rector of the parish.

In his sixteenth year Hyde entered King's College, Cambridge, where,

under Wheelock, professor of Arabic, he made rapid progress in Oriental

languages, so that, after only one year of residence, he was invited to

London to assist Brian Walton in his edition of the _Polyglott Bible_.

Besides correcting the Arabic, Persic and Syriac texts for that work,

Hyde transcribed into Persic characters the Persian translation of the

Pentateuch, which had been printed in Hebrew letters at Constantinople

in 1546. To this work, which Archbishop Ussher had thought well-nigh

impossible even for a native of Persia, Hyde appended the Latin version

which accompanies it in the _Polyglott_. In 1658 he was chosen Hebrew

reader at Queen's College, Oxford, and in 1659, in consideration of his

erudition in Oriental tongues, he was admitted to the degree of M.A. In

the same year he was appointed under-keeper of the Bodleian Library, and

in 1665 librarian-in-chief. Next year he was collated to a prebend at

Salisbury, and in 1673 to the archdeaconry of Gloucester, receiving the

degree of D.D. shortly afterwards. In 1691 the death of Edward Pococke

opened up to Hyde the Laudian professorship of Arabic; and in 1697, on

the deprivation of Roger Altham, he succeeded to the regius chair of

Hebrew and a canonry of Christ Church. Under Charles II., James II. and

William III. Hyde discharged the duties of Eastern interpreter to the

court. Worn out by his unremitting labours, he resigned his

librarianship in 1701, and died at Oxford on the 18th of February 1703.

Hyde, who was one of the first to direct attention to the vast treasures

of Oriental antiquity, was an excellent classical scholar, and there was

hardly an Eastern tongue accessible to foreigners with which he was not

familiar. He had even acquired Chinese, while his writings are the best

testimony to his mastery of Turkish, Arabic, Syriac, Persian, Hebrew and

Malay.

In his chief work, _Historia religionis veterum Persarum_ (1700), he

made the first attempt to correct from Oriental sources the errors of

the Greek and Roman historians who had described the religion of the

ancient Persians. His other writings and translations comprise _Tabulae

longitudinum et latitudinum stellarum fixarum ex observatione principis

Ulugh Beighi_ (1665), to which his notes have given additional value;

_Quatuor evangelia et acta apostolorum lingua Malaica, caracteribus

Europaeis_ (1677); _Epistola de mensuris et ponderibus serum sive

sinensium_ (1688), appended to Bernard's _De mensuris et ponderibus

antiquis; Abraham Peritsol itinera mundi_ (1691); and _De ludis

orientalibus libri II._ (1694).

With the exception of the _Historia religionis_, which was republished

by Hunt and Costard in 1760, the writings of Hyde, including some

unpublished MSS., were collected and printed by Dr Gregory Sharpe in

1767 under the title _Syntagma dissertationum quas olim ... Thomas

Hyde separatim edidit_. There is a life of the author prefixed. Hyde

also published a catalogue of the Bodleian Library in 1674.

HYDE, a market town and municipal borough in the Hyde parliamentary

division of Cheshire, England, 7½ m. E. of Manchester, by the Great

Central railway. Pop. (1901) 32,766. It lies in the densely populated

district in the north-east of the county, on the river Tame, which here

forms the boundary of Cheshire with Lancashire. To the east the outlying

hills of the Peak district of Derbyshire rise abruptly. The town has

cotton weaving factories, spinning mills, print-works, iron foundries

and machine works; also manufactures of hats and margarine. There are

extensive coal mines in the vicinity. Hyde is wholly of modern growth,

though it contains a few ancient houses, such as Newton Hall, in the

part of the town so called. The old family of Hyde held possession of

the manor as early as the reign of John. The borough, incorporated in

1881, is under a mayor, 6 aldermen and 18 councillors. Area, 3081 acres.

HYDE DE NEUVILLE, JEAN GUILLAUME, BARON (1776-1857), French politician,

was born at La Charité-sur-Loire (Nièvre) on the 24th of January 1776,

the son of Guillaume Hyde, who belonged to an English family which had

emigrated with the Stuarts after the rebellion of 1745. He was only

seventeen when he successfully defended a man denounced by Fouché before

the revolutionary tribunal of Nevers. From 1793 onwards he was an active

agent of the exiled princes; he took part in the Royalist rising in

Berry in 1796, and after the _coup d'état_ of the 18th Brumaire

(November 9, 1799) tried to persuade Bonaparte to recall the Bourbons.

An accusation of complicity in the infernal machine conspiracy of

1800-1801 was speedily retracted, but Hyde de Neuville retired to the

United States, only to return after the Restoration. He was sent by

Louis XVIII. to London to endeavour to persuade the British government

to transfer Napoleon to a remoter and safer place of exile than the isle

of Elba, but the negotiations were cut short by the emperor's return to

France in March 1815. In January 1816 de Neuville became French

ambassador at Washington, where he negotiated a commercial treaty. On

his return in 1821 he declined the Constantinople embassy, and in

November 1822 was elected deputy for Cosne. Shortly afterwards he was

appointed French ambassador at Lisbon, where his efforts to oust British

influence culminated, in connexion with the _coup d'état_ of Dom Miguel

(April 30, 1824), in his suggestion to the Portuguese minister to invite

the armed intervention of Great Britain. It was assumed that this would

be refused, in view of the loudly proclaimed British principle of

non-intervention, and that France would then be in a position to

undertake a duty that Great Britain had declined. The scheme broke down,

however, owing to the attitude of the reactionary party in the

government of Paris, which disapproved of the Portuguese constitution.

This destroyed his influence at Lisbon, and he returned to Paris to take

his seat in the Chamber of Deputies. In spite of his pronounced

Royalism, he now showed Liberal tendencies, opposed the policy of

Villèle's cabinet, and in 1828 became a member of the moderate

administration of Martignac as minister of marine. In this capacity he

showed active sympathy with the cause of Greek independence. During the

Polignac ministry (1829-1830) he was again in opposition, being a firm

upholder of the charter; but after the revolution of July 1830 he

entered an all but solitary protest against the exclusion of the

legitimate line of the Bourbons from the throne, and resigned his seat.

He died in Paris on the 28th of May 1857.

His _Mémoires et souvenirs_ (3 vols., 1888), compiled from his notes

by his nieces, the vicomtesse de Bardonnet and the baronne Laurenceau,

are of great interest for the Revolution and the Restoration.

HYDE PARK, a small township of Norfolk county, Massachusetts, U.S.A.,

about 8 m. S.W. of the business centre of Boston. Pop. (1890) 10,193;

(1900) 13,244, of whom 3805 were foreign-born; (1910 census) 15,507. Its

area is about 4½ sq. m. It is traversed by the New York, New Haven &

Hartford railway, which has large repair shops here, and by the Neponset

river and smaller streams. The township contains the villages of Hyde

Park, Readville (in which there is the famous "Weil" trotting-track),

Fairmount, Hazelwood and Clarendon Hills. Until about 1856 Hyde Park was

a farmstead. The value of the total factory product increased from

$4,383,959 in 1900 to $6,739,307 in 1905, or 53.7%. In 1868 Hyde Park

was incorporated as a township, being formed of territory taken from

Dorchester, Dedham and Milton.

HYDERABAD, or HAIDARABAD, a city and district of British India, in the

Sind province of Bombay. The city stands on a hill about 3 m. from the

left bank of the Indus, and had a population in 1901 of 69,378. Upon the

site of the present fort is supposed to have stood the ancient town of

Nerankot, which in the 8th century submitted to Mahommed bin Kasim. In

1768 the present city was founded by Ghulam Shah Kalhora; and it

remained the capital of Sind until 1843, when, after the battle of

Meeanee, it was surrendered to the British, and the capital transferred

to Karachi. The city is built on the most northerly hills of the Ganga

range, a site of great natural strength. In the fort, which covers an

area of 36 acres, is the arsenal of the province, transferred thither

from Karachi in 1861, and the palaces of the ex-mirs of Sind. An

excellent water supply is derived from the Indus. In addition to

manufactures of silk, gold and silver embroidery, lacquered ware and

pottery, there are three factories for ginning cotton. There are three

high schools, training colleges for masters and mistresses, a medical

school, an agricultural school for village officials, and a technical

school. The city suffered from plague in 1896-1897.

The DISTRICT OF HYDERABAD has an area of 8291 sq. m., with a population

in 1901 of 989,030, showing an increase of 15% in the decade. It

consists of a vast alluvial plain, on the left bank of the Indus, 216 m.

long and 48 broad. Fertile along the course of the river, it degenerates

towards the east into sandy wastes, sparsely populated, and defying

cultivation. The monotony is relieved by the fringe of forest which

marks the course of the river, and by the avenues of trees that line the

irrigation channels branching eastward from this stream. The south of

the district has a special feature in its large natural water-courses

(called _dhoras_) and basin-like shallows (_chhaus_), which retain the

rains for a long time. A limestone range called the Ganga and the

pleasant frequency of garden lands break the monotonous landscape. The

principal crops are millets, rice, oil-seeds, cotton and wheat, which

are dependent on irrigation, mostly from government canals. There is a

special manufacture at Hala of glazed pottery and striped cotton cloth.

Three railways traverse the district: (1) one of the main lines of the

North-Western system, following the Indus valley and crossing the river

near Hyderabad; (2) a broad-gauge branch running south to Badin, which

will ultimately be extended to Bombay; and (3) a metre-gauge line from

Hyderabad city into Rajputana.

HYDERABAD, HAIDARABAD, also known as the Nizam's Dominions, the

principal native state of India in extent, population and political

importance; area, 82,698 sq. m.; pop. (1901) 11,141,142, showing a

decrease of 3.4% in the decade; estimated revenue 4½ crores of Hyderabad

rupees (£2,500,000). The state occupies a large portion of the eastern

plateau of the Deccan. It is bounded on the north and north-east by

Berar, on the south and south-east by Madras, and on the west by Bombay.

The country presents much variety of surface and feature; but it may be

broadly divided into two tracts, distinguished from one another

geologically and ethnically, which are locally known from the languages

spoken as Telingana and Marathwara. In some parts it is mountainous,

wooded and picturesque, in others flat and undulating. The open country

includes lands of all descriptions, including many rich and fertile

plains, much good land not yet brought under cultivation, and numerous

tracts too sterile ever to be cultivated. In the north-west the

geological formations are volcanic, consisting principally of trap, but

in some parts of basalt; in the middle, southern and south-western parts

the country is overlaid with gneissic formations. The territory is well

watered, rivers being numerous, and tanks or artificial pieces of water

abundant, especially in Telingana. The principal rivers are the

Godavari, with its tributaries the Dudna, Manjira and Pranhita; the

Wardha, with its tributary the Penganga; and the Kistna, with its

tributary the Tungabhadra. The climate may be considered in general

good; and as there are no arid bare deserts, hot winds are little felt.

More than half the revenue of the state is derived from the land, and

the development of the country by irrigation and railways has caused

considerable expansion in this revenue, though the rate of increase in

the decade 1891-1901 was retarded by a succession of unfavourable

seasons. The soil is generally fertile, though in some parts it consists

of _chilka_, a red and gritty mould little fitted for purposes of

agriculture. The principal crops are millets of various kinds, rice,

wheat, oil-seeds, cotton, tobacco, sugar-cane, and fruits and

garden produce in great variety. Silk, known as _tussur_, the produce of

a wild species of worm, is utilized on a large scale. Lac, suitable for

use as a resin or dye, gums and oils are found in great quantities.

Hides, raw and tanned, are articles of some importance in commerce. The

principal exports are cotton, oil-seeds, country-clothes and hides; the

imports are salt, grain, timber, European piece-goods and hardware. The

mineral wealth of the state consists of coal, copper, iron, diamonds and

gold; but the development of these resources has not hitherto been very

successful. The only coal mine now worked is the large one at Singareni,

with an annual out-turn of nearly half a million tons. This coal has

enabled the nizam's guaranteed state railway to be worked so cheaply

that it now returns a handsome profit to the state. It also gives

encouragement to much-needed schemes of railway extension, and to the

erection of cotton presses and of spinning and weaving mills. The

Hyderabad-Godavari railway (opened in 1901) traverses a rich cotton

country, and cotton presses have been erected along the line. The

currency of the state is based on the _hali sikka_, which contains

approximately the same weight of silver as the British rupee, but its

exchange value fell heavily after 1893, when free coinage ceased in the

mint. In 1904, however, a new coin (the Mahbubia rupee) was minted; the

supply was regulated, and the rate of exchange became about 115 = 100

British rupees. The state suffered from famine during 1900, the total

number of persons in receipt of relief rising to nearly 500,000 in June

of that year. The nizam met the demands for relief with great

liberality.

The nizam of Hyderabad is the principal Mahommedan ruler in India. The

family was founded by Asaf Jah, a distinguished Turkoman soldier of the

emperor Aurangzeb, who in 1713 was appointed subahdar of the Deccan,

with the title of nizam-ul-mulk (regulator of the state), but eventually

threw off the control of the Delhi court. Azaf Jah's death in 1748 was

followed by an internecine struggle for the throne among his

descendants, in which the British and the French took part. At one time

the French nominee, Salabat Jang, established himself with the help of

Bussy. But finally, in 1761, when the British had secured their

predominance throughout southern India, Nizam Ali took his place and

ruled till 1803. It was he who confirmed the grant of the Northern

Circars in 1766, and joined in the two wars against Tippoo Sultan in

1792 and 1799. The additions of territory which he acquired by these

wars was afterwards (1800) ceded to the British, as payment for the

subsidiary force which he had undertaken to maintain. By a later treaty

in 1853, the districts known as Berar were "assigned" to defray the cost

of the Hyderabad contingent. In 1857 when the Mutiny broke out, the

attitude of Hyderabad as the premier native state and the cynosure of

the Mahommedans in India became a matter of extreme importance; but

Afzul-ud-Dowla, the father of the present ruler, and his famous

minister, Sir Salar Jang, remained loyal to the British. An attack on

the residency was repulsed, and the Hyderabad contingent displayed their

loyalty in the field against the rebels. In 1902 by a treaty made by

Lord Curzon, Berar was leased in perpetuity to the British government,

and the Hyderabad contingent was merged in the Indian army. The nizam

Mir Mahbub Ali Khan Bahadur, Asaf Jah, a direct descendant of the famous

nizam-ul-mulk, was born on the 18th of August 1866. On the death of his

father in 1869 he succeeded to the throne as a minor, and was invested

with full powers in 1884. He is notable as the originator of the

Imperial Service Troops, which now form the contribution of the native

chiefs to the defence of India. On the occasion of the Panjdeh incident

in 1885 he made an offer of money and men, and subsequently on the

occasion of Queen Victoria's Jubilee in 1887 he offered 20 lakhs

(£130,000) annually for three years for the purpose of frontier defence.

It was finally decided that the native chiefs should maintain small but

well-equipped bodies of infantry and cavalry for imperial defence. For

many years past the Hyderabad finances were in a very unhealthy

condition, the expenditure consistently outran the revenue, and the

nobles, who held their tenure under an obsolete feudal system, vied

with each other in ostentatious extravagance. But in 1902, on the

revision of the Berar agreement, the nizam received 25 lakhs (£167,000)

a year for the rent of Berar, thus substituting a fixed for a

fluctuating source of income, and a British financial adviser was

appointed for the purpose of reorganizing the resources of the state.

See S. H. Bilgrami and C. Willmott, _Historical and Descriptive Sketch

of the Nizam's Dominions_ (Bombay, 1883-1884).

HYDERABAD or HAIDARABAD, capital of the above state, is situated on the

right bank of the river Musi, a tributary of the Kistna, with Golconda

to the west, and the residency and its bazaars and the British

cantonment of Secunderabad to the north-east. It is the fourth largest

city in India; pop. (1901) 448,466, including suburbs and cantonment.

The city itself is in shape a parallelogram, with an area of more than 2

sq. m. It was founded in 1589 by Mahommed Kuli, fifth of the Kutb Shahi

kings, of whose period several important buildings remain as monuments.

The principal of these is the Char Minar or Four Minarets (1591). The

minarets rise from arches facing the cardinal points, and stand in the

centre of the city, with four roads radiating from their base. The Ashur

Khana (1594), a ceremonial building, the hospital, the Gosha Mahal

palace and the Mecca mosque, a sombre building designed after a mosque

at Mecca, surrounding a paved quadrangle 360 ft. square, were the other

principal buildings of the Kutb Shahi period, though the mosque was only

completed in the time of Aurangzeb. The city proper is surrounded by a

stone wall with thirteen gates, completed in the time of the first

nizam, who made Hyderabad his capital. The suburbs, of which the most

important is Chadarghat, extend over an additional area of 9 sq. m.

There are several fine palaces built by various nizams, and the British

residency is an imposing building in a large park on the left bank of

the Musi, N.E. of the city. The bazaars surrounding it, and under its

jurisdiction, are extremely picturesque and are thronged with natives

from all parts of India. Four bridges crossed the Musi, the most notable

of which was the Purana Pul, of 23 arches, built in 1593. On the 27th

and 28th of September 1908, however, the Musi, swollen by torrential

rainfall (during which 15 in. fell in 36 hours), rose in flood to a

height of 12 ft. above the bridges and swept them away. The damage done

was widespread; several important buildings were involved, including the

palace of Salar Jang and the Victoria zenana hospital, while the

beautiful grounds of the residency were destroyed. A large and densely

populated part of the city was wrecked, and thousands of lives were

lost. The principal educational establishments are the Nizam college

(first grade), engineering, law, medical, normal, industrial and

Sanskrit schools, and a number of schools for Europeans and Eurasians.

Hyderabad is an important centre of general trade, and there is a cotton

mill in its vicinity. The city is supplied with water from two notable

works, the Husain Sagar and the Mir Alam, both large lakes retained by

great dams. Secunderabad, the British military cantonment, is situated

5½ m. N. of the residency; it includes Bolaram, the former headquarters

of the Hyderabad contingent.

HYDER ALI, or Haidar 'Ali (c. 1722-1782), Indian ruler and commander.

This Mahommedan soldier-adventurer, who, followed by his son Tippoo,

became the most formidable Asiatic rival the British ever encountered in

India, was the great-grandson of a _fakir_ or wandering ascetic of

Islam, who had found his way from the Punjab to Gulburga in the Deccan,

and the second son of a _naik_ or chief constable at Budikota, near

Kolar in Mysore. He was born in 1722, or according to other authorities

1717. An elder brother, who like himself was early turned out into the

world to seek his own fortune, rose to command a brigade in the Mysore

army, while Hyder, who never learned to read or write, passed the first

years of his life aimlessly in sport and sensuality, sometimes, however,

acting as the agent of his brother, and meanwhile acquiring a useful

familiarity with the tactics of the French when at the height of their

reputation under Dupleix. He is said to have induced his brother to

employ a Parsee to purchase artillery and small arms from the Bombay

government, and to enrol some thirty sailors of different European

nations as gunners, and is thus credited with having been "the first

Indian who formed a corps of sepoys armed with firelocks and bayonets,

and who had a train of artillery served by Europeans." At the siege of

Devanhalli (1749) Hyder's services attracted the attention of Nanjiraj,

the minister of the raja of Mysore, and he at once received an

independent command; within the next twelve years his energy and ability

had made him completely master of minister and raja alike, and in

everything but in name he was ruler of the kingdom. In 1763 the conquest

of Kanara gave him possession of the treasures of Bednor, which he

resolved to make the most splendid capital in India, under his own name,

thenceforth changed from Hyder Naik into Hyder Ali Khan Bahadur; and in

1765 he retrieved previous defeat at the hands of the Mahrattas by the

destruction of the Nairs or military caste of the Malabar coast, and the

conquest of Calicut. Hyder Ali now began to occupy the serious attention

of the Madras government, which in 1766 entered into an agreement with

the nizam to furnish him with troops to be used against the common foe.

But hardly had this alliance been formed when a secret arrangement was

come to between the two Indian powers, the result of which was that

Colonel Smith's small force was met with a united army of 80,000 men and

100 guns. British dash and sepoy fidelity, however, prevailed, first in

the battle of Chengam (September 3rd, 1767), and again still more

remarkably in that of Tiruvannamalai (Trinomalai). On the loss of his

recently made fleet and forts on the western coast, Hyder Ali now

offered overtures for peace; on the rejection of these, bringing all his

resources and strategy into play, he forced Colonel Smith to raise the

siege of Bangalore, and brought his army within 5 m. of Madras. The

result was the treaty of April 1769, providing for the mutual

restitution of all conquests, and for mutual aid and alliance in

defensive war; it was followed by a commercial treaty in 1770 with the

authorities of Bombay. Under these arrangements Hyder Ali, when defeated

by the Mahrattas in 1772, claimed British assistance, but in vain; this

breach of faith stung him to fury, and thenceforward he and his son did

not cease to thirst for vengeance. His time came when in 1778 the

British, on the declaration of war with France, resolved to drive the

French out of India. The capture of Mahé on the coast of Malabar in

1779, followed by the annexation of lands belonging to a dependent of

his own, gave him the needed pretext. Again master of all that the

Mahrattas had taken from him, and with empire extended to the Kistna, he

descended through the passes of the Ghats amid burning villages,

reaching Conjeeveram, only 45 m. from Madras, unopposed. Not till the

smoke was seen from St Thomas's Mount, where Sir Hector Munro commanded

some 5200 troops, was any movement made; then, however, the British

general sought to effect a junction with a smaller body under Colonel

Baillie recalled from Guntur. The incapacity of these officers,

notwithstanding the splendid courage of their men, resulted in the total

destruction of Baillie's force of 2800 (September the 10th, 1780).

Warren Hastings sent from Bengal Sir Eyre Coote, who, though repulsed at

Chidambaram, defeated Hyder thrice successively in the battles of Porto

Novo, Pollilur and Sholingarh, while Tippoo was forced to raise the

siege of Wandiwash, and Vellore was provisioned. On the arrival of Lord

Macartney as governor of Madras, the British fleet captured Negapatam,

and forced Hyder Ali to confess that he could never ruin a power which

had command of the sea. He had sent his son Tippoo to the west coast, to

seek the assistance of the French fleet, when his death took place

suddenly at Chittur in December 1782.

See L. B. Bowring, _Haidar Ali and Tipu Sultan_, "Rulers of India"

series (1893). For the personal character and administration of Hyder

Ali see the _History of Hyder Naik_, written by Mir Hussein Ali Khan

Kirmani (translated from the Persian by Colonel Miles, and published

by the Oriental Translation Fund), and the curious work written by M.

Le Maître de La Tour, commandant of his artillery (_Histoire

d'Hayder-Ali Khan_, Paris, 1783). For the whole life and times see

Wilks, _Historical Sketches of the South of India_ (1810-1817);

Aitchison's Treaties, vol. v. (2nd ed., 1876); and Pearson, _Memoirs

of Schwartz_ (1834).

HYDRA (or SIDRA, NIDRA, IDERO, &c.; anc. _Hydrea_), an island of Greece,

lying about 4 m. off the S.E. coast of Argolis in the Peloponnesus, and

forming along with the neighbouring island of Dokos (Dhoko) the Bay of

Hydra. Pop. about 6200. The greatest length from south-west to

north-east is about 11 m., and the area is about 21 sq. mi.; but it is

little better than a rocky and treeless ridge with hardly a patch or two

of arable soil. Hence the epigram of Antonios Kriezes to the queen of

Greece: "The island produces prickly pears in abundance, splendid sea

captains and excellent prime ministers." The highest point, Mount Ere,

so called (according to Miaoules) from the Albanian word for wind, is

1958 ft. high. The next in importance is known as the Prophet Elias,

from the large convent of that name on its summit. It was there that the

patriot Theodorus Kolokotrones was imprisoned, and a large pine tree is

still called after him. The fact that in former times the island was

richly clad with woods is indicated by the name still employed by the

Turks, _Tchamliza_, the place of pines; but it is only in some favoured

spots that a few trees are now to be found. Tradition also has it that

it was once a well-watered island (hence the designation Hydrea), but

the inhabitants are now wholly dependent on the rain supply, and they

have sometimes had to bring water from the mainland. This lack of

fountains is probably to be ascribed in part to the effect of

earthquakes, which are not infrequent; that of 1769 continued for six

whole days. Hydra, the chief town, is built near the middle of the

northern coast, on a very irregular site, consisting of three hills and

the intervening ravines. From the sea its white and handsome houses

present a picturesque appearance, and its streets though narrow are

clean and attractive. Besides the principal harbour, round which the

town is built, there are three other ports on the north coast--Mandraki,

Molo, Panagia, but none of them is sufficiently sheltered. Almost all

the population of the island is collected in the chief town, which is

the seat of a bishop, and has a local court, numerous churches and a

high school. Cotton and silk weaving, tanning and shipbuilding are

carried on, and there is a fairly active trade.

Hydra was of no importance in ancient times. The only fact in its

history is that the people of Hermione (a city on the neighbouring

mainland now known by the common name of _Kastri_) surrendered it to

Samian refugees, and that from these the people of Troezen received it

in trust. It appears to be completely ignored by the Byzantine

chroniclers. In 1580 it was chosen as a refuge by a body of Albanians

from Kokkinyas in Troezenia; and other emigrants followed in 1590, 1628,

1635, 1640, &c. At the close of the 17th century the Hydriotes took part

in the reviving commerce of the Peloponnesus; and in course of time they

extended their range. About 1716 they began to build _sakturia_ (of from

10 to 15 tons burden), and to visit the islands of the Aegean; not long

after they introduced the _latinadika_ (40-50 tons), and sailed as far

as Alexandria, Constantinople, Trieste and Venice; and by and by they

ventured to France and even America. From the grain trade of south

Russia more especially they derived great wealth. In 1813 there were

about 22,000 people in the island, and of these 10,000 were seafarers.

At the time of the outbreak of the war of Greek independence the total

population was 28,190, of whom 16,460 were natives and the rest

foreigners. One of their chief families, the Konduriotti, was worth

£2,000,000. Into the struggle the Hydriotes flung themselves with rare

enthusiasm and devotion, and the final deliverance of Greece was mainly

due to the service rendered by their fleets.

See Pouqueville, _Voy. de la Grèce_, vol. vi.; Antonios Miaoules,

[Greek: Hypomnêma peri tês nêsou Hydras] (Munich, 1834); Id. [Greek:

Sunoptikê historia tôn naumachiôn dia tôn ploiôn tôn triôn nêsôn,

Hydras, Petsôn kai Psarôn] (Nauplia, 1833); Id. [Greek: Historia tês

nêsou Hydras] (Athens, 1874); G. D. Kriezes, [Greek: Historia tês

nêsou Hydras] (Patras, 1860).

HYDRA (watersnake), in Greek legend, the offspring of Typhon and

Echidna, a gigantic monster with nine heads (the number is variously

given), the centre one being immortal. Its haunt was a hill beneath a

plane tree near the river Amymone, in the marshes of Lerna by Argos. The

destruction of this Lernaean hydra was one of the twelve "labours"

of Heracles, which he accomplished with the assistance of Iolaus.

Finding that as soon as one head was cut off two grew up in its place,

they burnt out the roots with firebrands, and at last severed the

immortal head from the body, and buried it under a mighty block of rock.

The arrows dipped by Heracles in the poisonous blood or gall of the

monster ever afterwards inflicted fatal wounds. The generally accepted

interpretation of the legend is that "the hydra denotes the damp, swampy

ground of Lerna with its numerous springs ([Greek: kephalai], heads);

its poison the miasmic vapours rising from the stagnant water; its death

at the hands of Heracles the introduction of the culture and consequent

purification of the soil" (Preller). A euhemeristic explanation is given

by Palaephatus (39). An ancient king named Lernus occupied a small

citadel named Hydra, which was defended by 50 bowmen. Heracles besieged

the citadel and hurled firebrands at the garrison. As often as one of

the defenders fell, two others at once stepped into his place. The

citadel was finally taken with the assistance of the army of Iolaus and

the garrison slain.

See Hesiod, _Theog._, 313; Euripides, _Hercules furens_, 419;

Pausanias ii. 37; Apollodorus ii. 5, 2; Diod. Sic. iv. 11; Roscher's

_Lexikon der Mythologie_. In the article GREEK ART, fig. 20 represents

the slaying of the Lernaean hydra by Heracles.

HYDRA, in astronomy, a constellation of the southern hemisphere,

mentioned by Eudoxus (4th century B.C.) and Aratus (3rd century B.C.),

and catalogued by Ptolemy (27 stars), Tycho Brahe (19) and Hevelius

(31). Interesting objects are: the nebula _H. IV. 27 Hydrae_, a

planetary nebula, gaseous and whose light is about equal to an 8th

magnitude star; [epsilon] _Hydrae_, a beautiful triple star, composed of

two yellow stars of the 4th and 6th magnitudes, and a blue star of the

7th magnitude; _R. Hydrae_, a long period (425 days) variable, the range

in magnitude being from 4 to 9.7; and _U. Hydrae_, an irregularly

variable, the range in magnitude being 4.5 to 6.

HYDRACRYLIC ACID (ethylene lactic acid), CH2OH·CH2·CO2H. an organic

oxyacid prepared by acting with silver oxide and water on

[beta]-iodopropionic acid, or from ethylene by the addition of

hypochlorous acid, the addition product being then treated with

potassium cyanide and hydrolysed by an acid. It may also be prepared by

oxidizing the trimethylene glycol obtained by the action of hydrobromic

acid on allylbromide. It is a syrupy liquid, which on distillation is

resolved into water and the unsaturated acrylic acid, CH2:CH·CO2H.

Chromic and nitric acids oxidize it to oxalic acid and carbon dioxide.

Hydracrylic aldehyde, CH2OH·CH2·CHO, was obtained in 1904 by J. U. Nef

(_Ann._ 335, p. 219) as a colourless oil by heating acrolein with water.

Dilute alkalis convert it into crotonaldehyde, CH3·CH:CH·CHO.

HYDRANGEA, a popular flower, the plant to which the name is most

commonly applied being _Hydrangea Hortensia_, a low deciduous shrub,

producing rather large oval strongly-veined leaves in opposite pairs

along the stem. It is terminated by a massive globular corymbose head of

flowers, which remain a long period in an ornamental condition. The

normal colour of the flowers, the majority of which have neither stamens

nor pistil, is pink; but by the influence of sundry agents in the soil,

such as alum or iron, they become changed to blue. There are numerous

varieties, one of the most noteworthy being "Thomas Hogg" with pure

white flowers. The part of the inflorescence which appears to be the

flower is an exaggerated expansion of the sepals, the other parts being

generally abortive. The perfect flowers are small, rarely produced in

the species above referred to, but well illustrated by others, in which

they occupy the inner parts of the corymb, the larger showy neuter

flowers being produced at the circumference.

There are upwards of thirty species, found chiefly in Japan, in the

mountains of India, and in North America, and many of them are familiar

in gardens. _H. Hortensia_ (a species long known in cultivation In China

and Japan) is the most useful for decoration, as the head of flowers

lasts long in a fresh state, and by the aid of forcing can be had for a

considerable period for the ornamentation of the greenhouse and

conservatory. Their natural flowering season is towards the end of the

summer, but they may be had earlier by means of forcing. _H. japonica_

is another fine conservatory plant, with foliage and habit much

resembling the last named, but this has flat corymbs of flowers, the

central ones small and perfect, and the outer ones only enlarged and

neuter. This also produces pink or blue flowers under the influence of

different soils.

The Japanese species of hydrangea are sufficiently hardy to grow in any

tolerably favourable situation, but except in the most sheltered

localities they seldom blossom to any degree of perfection in the open

air, the head of blossom depending on the uninjured development of a

well-ripened terminal bud, and this growth being frequently affected by

late spring frosts. They are much more useful for pot-culture indoors,

and should be reared from cuttings of shoots having the terminal bud

plump and prominent, put in during summer, these developing a single

head of flowers the succeeding summer. Somewhat larger plants may be had

by nipping out the terminal bud and inducing three or four shoots to

start in its place, and these, being steadily developed and well

ripened, should each yield its inflorescence in the following summer,

that is, when two years old. Large plants grown in tubs and vases are

fine subjects for large conservatories, and useful for decorating

terrace walks and similar places during summer, being housed in winter,

and started under glass in spring.

_Hydrangea paniculata_ var. _grandiflora_ is a very handsome plant; the

branched inflorescence under favourable circumstances is a yard or more

in length, and consists of large spreading masses of crowded white

neuter flowers which completely conceal the few inconspicuous fertile

ones. The plant attains a height of 8 to 10 ft. and when in flower late

in summer and in autumn is a very attractive object in the shrubbery.

The Indian and American species, especially the latter, are quite hardy,

and some of them are extremely effective.

HYDRASTINE, C21H21NO6, an alkaloid found with berberine in the root of

golden seal, _Hydrastis canadensis_, a plant indigenous to North

America. It was discovered by Durand in 1851, and its chemistry formed

the subject of numerous communications by E. Schmidt and M. Freund (see

_Ann._, 1892, 271, p. 311) who, aided by P. Fritsch (_Ann._, 1895, 286,

p. 1), established its constitution. It is related to narcotine, which

is methoxy hydrastine. The root of golden seal is used in medicine under

the name hydrastis rhizome, as a stomachic and nervine stimulant.

HYDRATE, in chemistry, a compound containing the elements of water in

combination; more specifically, a compound containing the monovalent

hydroxyl or OH group. The first and more general definition includes

substances containing water of crystallization; such salts are said to

be hydrated, and when deprived of their water to be dehydrated or

anhydrous. Compounds embraced by the second definition are more usually

termed _hydroxides_, since at one time they were regarded as

combinations of an oxide with water, for example, calcium oxide or lime

when slaked with water yielded calcium hydroxide, written formerly as

CaO·H20. The general formulae of hydroxides are: M^iOH, M^(ii)(OH)2,

M^(iii)(OH)3, M^(iv)(OH)4, &c., corresponding to the oxides M2^iO,

M^(ii)O, M2^(iii)O3, M^(iv)O2, &c., the Roman index denoting the valency

of the element. There is an important difference between non-metallic

and metallic hydroxides; the former are invariably acids (oxyacids), the

latter are more usually basic, although acidic metallic oxides yield

acidic hydroxides. Elements exhibiting strong basigenic or oxygenic

characters yield the most, stable hydroxides; in other words, stable

hydroxides are associated with elements belonging to the extreme groups

of the periodic system, and unstable hydroxides with the central

members. The most stable basic hydroxides are those of the alkali

metals, viz. lithium, sodium, potassium, rubidium and caesium, and of

the alkaline earth metals, viz. calcium, barium and strontium; the most

stable acidic hydroxides are those of the elements placed in groups VB,

VIB and VIIB of the periodic table.

HYDRAULICS (Gr. [Greek: hydôr], water, and [Greek: aulos], a pipe), the

branch of engineering science which deals with the practical

applications of the laws of hydromechanics.