in its most common acceptation, implies the whole space of time through which anything has existed; but the term is frequently used in other senses too vague and figurative to be included under any general definition.

The age of this habitable globe has been much disputed. Cuvier, Dolomieu, Deluc, and Greenough, concur in thinking that not more than 5000 or 6000 years have elapsed since the creation of man.—Cuvier's Theory of the Earth.

Josephus estimates the period that elapsed from the creation of man to the deluge at 2256 years. The antediluvian or obscure age was succeeded by the fabulous or heroic age, in which the exploits of the gods and heroes of the ancients were supposed to have been performed, extending down to the first Olympiad, B.C. 776. To this succeeded the historic age, terminating with the destruction of Carthage by the Romans in B.C. 146. The period immediately following has been denominated the Roman age, which extended down to the fall of the Roman Empire in the West, A.D. 476. The middle age is defined by some writers as that period extending from the time of Constantine in the fourth century to the capture of Constantinople by the Turks, A.D. 1453; but it is more usually defined as dating from the division of the empire of Theodosius, A.D. 395, down to the time of the emperor Maximilian I., in the beginning of the sixteenth century, when the Germanic Empire was first divided into circles. It has also been termed the barbarous age, and is commonly divided into two periods; the first extending from the sixth to the ninth century, when learning was almost extinct in Europe; the second dating from the ninth century, when letters again began to flourish.

The term age has been applied metaphorically to supposed epochs in human civilisation; thus, in the mythology of the Greek and Roman poets, there were four ages, distinguished as the Golden, the Silver, the Brazen, and the Iron; the three latter being successively a farther declension from the first or pristine state of purity and bliss. In the first, mankind were supposed to have subsisted on the spontaneous productions of nature, in a state of innocence and happiness, without the necessity of laws or civil government. In the second, the earth no longer yielded its fruits untillied, and the human heart first began to be corrupted. In the third, emulation and discord arose, men grew more and more selfish, and laws became necessary to restrain human depravity. In the fourth, Astraea, the last of the celestial sojourners on earth, withdrew from the contemplation of human wickedness, and abandoned the world to violence, the scourge of wars, and desolation. The propriety of inverting the order of these four ages has been urged, on the ground that civilisation has been steadily progressive from the earliest times down to the present. However this may be, the universal tradition of a golden age, or primeval state of bliss, seems to favour the opinion that the light of revealed religion was never wholly extinguished, but may be traced exerting a remote influence on the human mind, long after the source whence it was derived was lost to the heathen world.

The term age is often used to denote any period that has been distinguished by the occurrence of remarkable events, or by the appearance of eminent persons; e.g. the age of the crusades, of chivalry, of the reformation; or, the age of Pericles, of Alexander, of Augustus, of Trajan, of Alfred, of Chaucer, the Elizabethan age,—the age of Shakspeare, of Newton, &c. The reign of Queen Anne has sometimes been styled the Augustan age of English literature, from its supposed resemblance to that illustrious period in the literary history of Rome.

The several ages at which, with us, individuals become legally qualified for certain ends, may be stated shortly as follows, commencing with the earliest age so cognisable. An infant under 10½ years of age is not amenable to the laws; but above that age, the offender, without distinction of sex, is responsible, if found to be capax dolii, or competent to distinguish between right and wrong; and although 14 is fixed by the civil law as the age of criminal responsibility, capital punishment has once been inflicted, for an artfully-concealed murder (in 1629), at the early age of 8 years. After 12, the oath of allegiance may be taken. The age of puberty in either sex is 14, when each may choose guardians; and formerly, if their discretion was proved, a male at 14, and a female at 12, could execute a valid testament of personal property, though not of lands: but by Vict. 1, c. 26, it is enacted that no person can execute any valid will under 21 years of age. The nubile age was fixed by the Roman law at 14 for males, and 12 for females, which are the respective legal ages with us, when either sex may consent to marriage, with the approval of guardians; yet it may be observed, that many minors contract marriages without such sanction. In France, by the Code-Napoleon, the nubile age is 18 for males, and 15 for females, under similar restriction. At 17, a person of either sex may be an executor or executrix. The sovereignty of this realm is assumed at 18; though the law, according to Blackstone, recognises no minority in the heir to the throne. The age of majority, which gives to both sexes the free disposal of themselves and their property, personal and real, is 21; at which age a man is capable of enjoying most civil privileges. In France the age of majority is the same. Among the Romans, minority did not cease until the completion of the 25th year. A seat in the British Parliament may be taken at 21; in the American House of Representatives at 25, and in the Senate at 30. In France, the requisite age for an elector was 25; for a seat in the Chamber of Deputies, 30; and in the Chamber of Peers it was 25, though no member of that Assembly could vote till 30. At Rome, during the time of the republic, 32 was probably the senatorial age; but it was fixed by Augustus at 25, and so it continued during the time of the empire. It appears that previous to the year B.C. 179, a citizen was eligible to most offices in Rome after the completion of his 27th year; but at that time it was enacted that the earliest age for the quaestorship should be 31; for the aedileship, 36; for the praetorship, 40; and for the consulate, 43,—though the law respecting this last was frequently infringed, especially by Julius Cæsar. The age for admission to the Spartan Gerusia, or Council of Elders, was 60. In the Church of England, a candidate for holy orders may become a deacon at 23; be ordained a priest at 24; and at 30 is eligible to a bishopric. A licentiate of the Church of Scotland must not be under 21 years of age. The same is the age for admission to the English or Scottish Bar, and for receiving the degree of Doctor of Medicine in the University of Edinburgh, and in most other colleges.

Age of Man.—We learn from the oldest and most authentic record of our race that the age of man has greatly diminished from his first creation. The antediluvians attained an age nearly approaching one thousand years; and during all the period from the creation of man to the deluge, his age did not diminish, seeing that the last of the antediluvians, Noah, lived 950 years, or twenty years longer than Adam. From the period of the deluge however, the age of man was suddenly shortened; none born after that event reached the age of 500 years, and even that age was lessened by a-half; and again gradually shortened during succeeding generations, till in the days of Moses it had reached that standard from which it has not since departed. "The days of our years are threescore years and ten; and if by reason of strength they be fourscore years, yet is their strength labour and sorrow."

As the most remarkable instance of longevity in modern times we may notice Petratsch Czartan, a Hungarian peasant, who was born in 1537, and died in 1722, at the patriarchal age of 185 years. See Longevity.

As applied to man the term age is often used to express the duration of a generation. The ancients in using the term in this sense intended to express a period of thirty years. Thus Nestor is said to have lived three ages when he was ninety years old. It is a remarkable instance of the correct observation of the ancients, that the statistics of the countries of Europe at present show that thirty years is the mean term of the life of a generation. In our more favourable isle this mean age or mean duration of a generation is somewhat higher, being for London about thirty-one years, and for England and Wales thirty-three years;—residence in the country being more favourable to health and longevity than residence in towns. As a general rule, when the population is rapidly increasing, as in America, the mean age or mean duration of a generation is lower than in an old country where the population is nearly stationary.

The age of man has been variously divided into four, six, and seven stages:—The latter being not only the poetical, but the most correct physiologically. These seven stages are, 1. Infancy; 2. Childhood; 3. Boy or Girlhood; 4. Adolescence; 5. Manhood or Womanhood; 6. Age; 7. Old Age or second childhood. These different periods are more or less distinctly marked. Infancy is attended with peculiar dangers, and extends to about the end of the second year of life, by which time the first dentition is completed. Childhood extends from this period to about the seventh year, the termination of this period being marked by the dropping out of the middle incisors, and the appearance of the second set of teeth. Boyhood extends from the seventh to about the fourteenth year, and during this period all the first or milk set of teeth are replaced by the permanent ones. Adolescence, youth, or puberty, generally commences somewhat earlier in the female than in the male; and extends in both from about the fourteenth to the twenty-first year of life. It commences with the evolution of the generative system; and during this period the body attains its full height. Womanhood lasts distinctly from the 21st to the 45th or 50th year, most generally to about the latter, at which period the female ceases to be capable of procreation, and her constitution undergoes a complete change. Though less attention has been paid to the duration of this stage in the male, it is an unquestionable fact that about the 49th or 50th year of life the male constitution also undergoes a change, and fully justifies the notion of the ancients as to climacteric periods of life. The period of life we have termed age, extending generally from the 49th to the 63rd year of life, has been too commonly, but most erroneously, confounded with the next stage, viz. old age. During the earlier portion of this period, the body, instead of tending to decay, tends rather to obesity. The maturity and strength of intellect too, continue for the most part undiminished during all this stage. In old age, the last stage of all, the body begins to shrink, the muscles lose their tone, and not being able to sustain the weight of the body, allow the limbs to bend more or less. The hair becomes white; the teeth drop out; all the senses are blunted; the intellect is feeble; the circulation becomes weaker; and death naturally closes the scene.

Age of Animals.—Comparatively few observations have been made on the ages of animals. From observations founded on some of the domestic animals, it has been stated that the duration of the life of an animal is usually seven or eight times longer than the period it takes to arrive at its full growth. This rule applies pretty well to horses, oxen, sheep, dogs, the camel, and even the elephant, but is quite inapplicable to man, to many quadrupeds, birds, reptiles, or fishes. Even were the rule applicable to animals, it would not enable us from an examination of the animal to find out its age; hence other means have been devised for determining the age with a greater degree of certainty. Thus the age of the horse may be pretty accurately determined by the examination of the incisive teeth or nippers, but even these lose mark at ten years, and the age of the horse after that period cannot be accurately ascertained. (See Horse.) In horned cattle and deer, the age may, for a certain period of their life, be pretty accurately guessed at by the appearance of the horns. All deer shed their horns annually, and, in the males of many species, each successive year adds one more branch to the horns, till they attain a certain size, beyond which they do not increase. Thus the common stag during the first year of its life has a simple horn, called a pricket. This falls off during the second year of its life, and is replaced by a horn with one branch or antler. This in its turn falls off during the third year, to be replaced by a horn with two antlers; and so on till the eighth year of life, when the horns cease to acquire additional antlers, so that the future age of the animal cannot be ascertained. The horns of oxen, sheep, goats, and antelopes, being permanent, are simple, and grow in a different manner. As a general rule, for a certain number of years, a ring is added annually to the base of the horn, and by this mark their age may be pretty accurately ascertained. In sheep and goats the horn which grows the first year of life is smooth; but every year after this a ring more or less wrinkled is added to the base of the horn, and indicates their age. It is probable that the same law prevails with the antelopes. In oxen, again, the horn continues smooth for the first three years of life, but every year thereafter, a wrinkled ring is added to the base of the horns. By counting the number of these rings, therefore, and adding three for the first years when the horns are smooth, the age may be pretty accurately known.

No sure indications exist by which the ages of birds, reptiles, or fishes, may be known.

Several curious facts, however, have been collected relative to the age attained by various animals. The Indians believe that the elephant lives three centuries; and authentic instances are on record of their having been kept in captivity for 130 years, their age being unknown at the period of their being taken captive. Camels live from 40 to 50 years; horses from 25 to 30 years, if not overworked; oxen about 20 years; sheep 8 or 9 years; dogs 12 to 14 years.

The longevity of some birds appears to be very great. The swan has been known to live 100 years. Birds of prey, and especially the eagle, have survived a century; and several instances are on record of the raven having exceeded that period. Parrots have been known to live 60 and 80 years. The gallinaceous birds, as domestic poultry and pheasants, have short lives, rarely exceeding 12 or 15 years.

Of reptiles, so far as known, the tortoise seems to attain the greatest age. One was placed in the archiepiscopal garden at Lambeth in the year 1633 during the life of Archbishop Laud, and it survived till the year 1753, when it perished from accident rather than old age. The toad is known to live about 15 years. Nothing, however, is known relative to the age of the gigantic boa or other serpents.

Of fishes, the carp has been known to attain the age of 200 years. We have seen the common river trout confined in a well, one 30 years, the other upwards of 50 years, and both still living. Rzaczynski mentions a pike which lived in a pond a period of 90 years. Gesner relates that in 1497 an enormous pike was caught in a lake near Haillerun in Swabia, with a brazen ring attached to it, bearing that it was put into the lake in the year 1230; which ring is still preserved at Mannheim. This pike, therefore, appears to have reached the patriarchal age of 267 years at least.

Of the ages of the lower animals little is known. That of insects has received most attention, and it is instructive to note that, though the first period of life of many of these animals (the caterpillar or grub) extends through a period of several months, or even years, the great majority live but a few days or weeks after they attain their perfect form. The ephemera does not enjoy the pleasures of its aerial life above a few hours; the same day which brings it into perfect being seeing it die.

It may be observed, as a general law of nature applicable to all organised beings, that early maturity indicates shortness of life, and that they are usually prolific in the inverse ratio of their duration.

Age of Plants and Trees.—The great majority of plants which adorn the face of the earth are annual and biennial— that is, spring from the seed, blossom, ripen their seeds, and die, in one or two years. Most of those, however, which rise to the stature of shrubs or trees attain considerable age. Of the palm trees it is very questionable whether any attain a greater age than 200 years. As this class of plants, after attaining a certain diameter, shoots up a straight stem which never increases in diameter, and all the new wood which every leaf necessarily produces insinuates its fibres into the centre of the trunk, this trunk or stem necessarily becomes more and more condensed, so that at last life or vegetation ceases, from the fibres and vessels being too much compressed to conduct the sap to the growing top. Exogenous trees, or those which grow by the addition of an annual layer of wood superimposed or encircling those already formed, may continue growing for an indefinite length of time, and several of the trees which exist on the surface of the globe may have witnessed the Noachian deluge. Of this class is the Baobab tree of Senegal, with a girth of nearly 300 feet, reckoned by Adamson to be 5150 years old; the gigantic *Dracaena draco* at Orotava, in Teneriffe, which Humboldt classes with the Baobab as "the oldest habitants of our planet;" the deciduous cypress at Chapultepec in Mexico, supposed by the younger De Candolle to be of equal antiquity with the two former; the chestnut trees on Mount Etna, of which one is 180 feet in circumference, another 70 feet, and another 64 feet; and the oriental plane tree, in the valley of Bujukdere, near Constantinople, which measures 150 feet in circumference. Of trees of known age are the eight olive trees which still exist in the garden on the Mount of Olives at Jerusalem, and which historical documents prove to have existed prior to the taking of that city by the Turks. These trees, consequently, exceed 800 years in age. The yew tree is proverbial for the great age it sometimes attains. The yews at Fountains Abbey in Yorkshire were considered old trees when the Abbey was erected in 1132, and are probably more than 1200 years old. The old yew formerly in Fortingal churchyard, in Perthshire, was probably double that age, and was 56½ feet in circumference. At Ankerwyke House, near Staines, is the yew tree known as a tree of note before the day of Runnymede (5th June 1215); and many other instances might be adduced. Oaks have frequently been cut down in the New Forest which presented 300 and 400 concentric rings, each of which indicated a year's growth. But many oaks exist of much larger dimensions, and consequently of much greater age, probably exceeding 1200 years. Thus, an oak was felled at Norburg, as is related by Dr Plot, of the enormous circumference of 45 feet, and the Boddington oak, in the vale of Gloucester, was 54 feet in circumference. Damory's oak in Dorsetshire was 68 feet in circumference, and, according to the common calculation, was 2000 years of age. Wallace's oak at Ellersley, near Paisley, must be at least 700 years old, but its age is trifling as compared with the aforementioned giants. The cypress has been known to attain the age of 800 years. A lime tree in the Grisons, measuring 51 feet in circumference, is known to be upwards of 580 years old. It is doubtful whether the elm ever reaches the age of 300 years. One planted by Henry IV. was standing at the Luxembourg, at the commencement of the French Revolution. Bacon's elms in Gray's Inn Walks, planted in 1600, decayed prematurely in 1720; and the elms in the Long Walk at Windsor, planted in the beginning of the last century, are evidently past their prime, though still noble trees.