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exterior to the circle, and touching it in five points; then it is still evident, tnat as the circle is wholly contained within the pentagon, it must be smaller than that which contains it. But if the pentagon be described within the circular, touching it at the five angular points, then a similar train of reasoning will show that the circle is larger than the pentagon which it contains. Extending our researches on a similar principle, we prove clearly that a circle is always smaller than a polygon of any number of sides exterior to it; but larger than any polygon contained within it; and this would be equally true if the polygon contained a million sides, and presented a contour not differing, to the eye, from

that of a circle.

Now the next stage in the reasoning is-that by means of the most simple geometry, the exact periphery or circumference, and the exact area, of any figure bounded by straight lines, may be determined with rigorous accuracy; and if we draw two polygons,-say of one hundred sides one within and the other without a circle, we can ascertain the exact areas of those polygons, and affirm that the area of the circle is greater than a certain amount, and less than another certain amount. These two amounts, if the number of sides in the polygons be so large as we here suppose, may be so very nearly alike that either one will give the area of the circle with great

closeness.

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By means more or less similar to these, Archimedes found, that if the diameter be called 7, then the circumference will be nearly 22, and that if the square of the diameter be called 14, then the area of the circle will be equal to about 11: this computation was slightly in error, and gave to the area of the circle, too great a measure by about part of the whole. The Hindoos, who were in early ages famous for their skill in mathematics, found that if the diameter of the circle 1, then the area would be 31% an approximation much closer than the other, for it was not in error so much as one-thousandth part of a square inch when the diameter of the circle was one foot. At a later period, however, a European mathematician named Metius discovered a method which makes an extraordinary approach to accuracy, and is at the same time the most simple and easy to be remembered of all that have been proposed. He found that if the diameter of a circle be considered equal to 113, then the circumference would equal 355, or if we multiply the square of the radius by 355, and divide by 133, the area will be given. Now this method is so very nearly correct, that the area of a circle one foot in diameter is given within the fifty thousandth part of a square inch. The numbers employed are easily remembered, for they consist of duplications of the first three odd numbers in regular order, 113355.

Other mathematicians carried the approximation yet closer. Ludolph Van Ceulen worked it out to 36 places of figures, showing that, if the diameter be 1, the circumference will be

3.14159265358979323846264338327950288;

or, that if the last figure be 8, the result will be a little below the truth, and if 9, a little above it. Mr. Sharp, an English mathematician of the seventeenth century, carried the approximation to 72 places of figures; Mr. John Machin to 100 figures: and, eclipsing all others, M. de Lagny worked it out to 128 places of figures. Of the degree of accuracy obtained in this last-named computation, Montucla says:-" If we suppose a circle, the diameter of which is a thousand million of times greater than the distance between the sun and the earth, the error in the circumference would be a thousand million times less than the thickness of a hair."

But the important part of the matter has yet to be stated. None of these computations are quite correct. They approach within limits quite near enough for all practical purposes; but they all deviate a little from the

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truth; and eminent mathematicians have shown that the rigorous solution is impossible; in other words, that there are no numbers or collections of numbers which will give the exact ratio of the circumference or of the area of a circle to its diameter.

Persons but slightly acquainted with mathematics have however, puzzled their brains to effect this object; and many ludicrous instances have been adduced by Montucla and Hutton to illustrate this subject. The Cardinal de Cusa rolled a cylinder over a plane, till the point which was first in contact with the plane, touched it again; and then, by a train of reasoning wholly destitute of geometrical precision, he endeavoured to determine the length of the line thus described. Oliver de Serres weighed a circle, and also a triangle equal to an equilateral triangle inscribed within the circle, and imagined that the former was exactly equal to two of the latter; forgetting that the double of this triangle is equal to the hexagon inscribed within the circle, and therefore smaller than the circle itself. A Frenchman named Mathoulon, who, from being a manufacturer of stuffs at Lyons, commenced geometer, claimed the merit of having solved this problem, and deposited one thousand crowns as a reward to any person who should prove that his solution was not correct. The proof was given by M. Nicole, a Member of the French Academy of Sciences, who gave the reward to the General Hospital at Lyons.

Another Frenchman announced that he had succeeded in the problem, and challenged the world to refute him, depositing ten thousand livres as the stake. He reduced the problem to the mechanical process of dividing a circle into quadrants, and then turning these with the angles outwards, so as to form a square, which he asserted to be equal to the circle. Three persons claimed the reward, and the cause was tried at the Châtelet of Paris; but the judges declared that a person's fortune ought not to be diminished on account of the errors of his judgment, unless they were preju dicial to society, whereupon the King decreed that the proposal should be void; and the Academy of Sciences recommended the man to study the elements of geometry.

In 1585 a Spanish friar published a most whimsical work; at least so it appears to others, though we doubt not that he deemed it a work of serious importance. It was a dialogue between himself and a circle, in which the latter thanks him very courteously for having solved its quadrature. Others connected the quadrature of the circle with subjects to which it has no kind of relation. For instance one person discovered a method which he thought would not only quadrate a circle, but would also assist in converting Jews, Pagans, and Mohammedans to Christianity; another fancied he saw a connexion between his method and the vision of Ezekiel; a third thought that the doctrines of Original Sin and of the Trinity, were elucidated by this method of quadrating the

circle.

But it would be useless to follow out the subject further; as most of the instances recorded present similar indications of absence of sound judgment and of all geometrical knowledge. Suffice it to say that the quadrature of the circle, in a geometrical sense, cannot be effected; but that all the useful purposes to which such a problem might be applied, can be attained sufficiently near by the approximative methods before alluded to, of which the most useful is, Diameter: 113:: the Circumference: 355, or the Diameter is to the Circumference, as 113 is to 355; for it matters not whether the second and third of the proportion be transposed.

LONDON:

JOHN WILLIAM PARKER, WEST STRAND. PUBLISHED IN WEEKLY NUMBERS, PRICE ONE PENNY, AND IN MONTHLY PARTS, PRICE SIXPENCE.

Sold by all Booksellers and Newsvenders in the Kingdom.

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We have mentioned that the Grand Master of the Temple, Arnold de Torroge, died on his journey to England, as he travelled in company with the patriarch Heraclius, on a mission to Henry II. He was succeeded by Gerard de Riderfort, in 1185. The patriarch returned in disgust and discontent to the Holy Land, for he was unable to persuade the king to perform the promised penance, ie, to hasten to the succour of the distressed Christians at Jerusalem. Before quitting the king he is said to have used threatenings and warnings, and to have foretold that the monarch would be forsaken of God, since he had at that time forsaken His holy cause. But it appears from authentic records, that this same patriarch was ill qualified to deal out these denunciations on the faults of others, since he was himself living in open contempt of the precepts of the moral law. There is a sad detail of vice and profligacy connected with his name, which we have no intention of laying before our readers, but which we thus allude to, to show what was the state of the Latin church at that time. One of the old chroniclers attributes the loss of Jerusalem to such causes as these, and says, "when Jesus Christ saw the iniquity and wickedness which they committed, in the very place Where He was crucified, He could no longer suffer it."

The period of the truce with Saladin was passed by the Templars and the rest of the Christians in ineffectual endeavours to gain sufficient strength for the coming

VOL. XXI.

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contest, and, unfortunately, in stormy discussions respecting the government of their own kingdom. Meanwhile Saladin was carefully consolidating and strengthening his power, exhorting his followers, and raising their enthusiasm to the highest pitch. The first encounter took place near the brook Kishon, where one of Saladin's sons (Malek-el-Afdal, Most excellent Prince), at the head of seven thousand Mussulmen, cut to pieces a body of united Templars and Hospitallers, who had rashly engaged with them. The Grand Master of the Hospital was left dead upon the field, and only the Grand Master of the Temple and two knights broke through the ranks of the Moslems and made their escape. This disastrous battle took place on the 10th of May, 1187.

On the 4th of July of the same year the fate of the holy city was decided at the great battle of Tiberias. The Templars led the van of the Christian army against the hosts of Saladin, which amounted to eighty thousand horse and foot, and appeared over the hilly country like "mountains in movement, or like the agitated waves of the sea." The Templars are also described as "horrible in arms, having their whole bodies cased in triple mail." The latter rushed like lions on the infidels and nothing could withstand their furious charge. Saladin set fire to the grass and shrubs between the two armies, and the wind blew the smoke and flames in the faces of the

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Christians and their horses. Arabian writers describe | the tremendous scene in vivid language. They compare it to the day of judgment, for the day was turned into night, and the face of the sun was obscured. The following extract from one of their writers is given by Mr. Addison: "The sons of paradise and the children of fire then decided their terrible quarrel; the arrows rustled through the air like wings of innumerable sparrows, the sparks flew from the coats of mail and the glancing sabres, and the blood, spurting forth from the bosom of the throng, deluged the earth like the rains of heaven."

To the patriarch Heraclius belonged the duty of bearing the cross in front of the Christian army, but this cowardly ecclesiastic confided the sacred symbol to the care of the bishops of Ptolemais and Lydda. The Moslems were completely victorious in the terrible conflict; the bishop of Ptolemais was slain; the bishop of Lydda was taken captive, together with the King of Jerusalem and the Grand Master of the Temple. The Templars and the Hospitallers were all slain or taken prisoners. Saladin's secretary writes,

I saw the mountains and the plains, the hills and the valleys, covered with their dead. I saw their fallen and deserted banners sullied with dust and with blood. I saw their heads broken and battered, their limbs scattered abroad, and the blackened corses piled one upon another like the stones of the builders: I called to mind the words of the Koran, "The infidel shall say, What am I but dust? t??? Their king and their cross were captured, that cross before which they bow the head and bend the knee; which they bear aloft and worship with their eyes; they say that it is the identical wood to which the god whom they adore, was fastened. They had adorned it with fine gold and brilliant stones; they carried it before their armies; they bowed towards it with respect. It was their first duty to defend it, and he who should desert it would never enjoy peace of mind. The capture of this cross was more grievous to them than the captivity of their king. Nothing can compensate them for the loss of it. It was their god, they prostrated themselves in the dust before it, and sang hymns when it

was raised aloft.

Immediately after the battle Saladin caused the brave Prince Reginald de Chatillon to be beheaded, but reserved the Grand Master of the Temple and the King of Jerusalem in expectation of a splendid ransom.

The concluding scene of this tragedy was enacted on the Christian Sabbath, two days after the battle. All the captives belonging either to the order of Templars or Hospitallers were led to an eminence above Tiberias in full view of the beautiful lake of Gennesareth. There the Moslems were drawn up in battle-array, and there, in the midst of scenery consecrated by the performance of so many of the Saviour's miracles, the captives were called upon to deny their Lord and to embrace the Moslem faith. They refused, to a man, and were all decapitated in the presence of Saladin, by the zealots of his army, and the doctors and expounders of the law. The Knights Templars contested with each other which should be the first to suffer and it was believed by the Christians, in accordance with the superstitious notions of the times, that celestial rays of light played about the corses of the holy martyrs.

Saladin now proceeded rapidly in his conquests: thirty or forty cities and castles fell into his hands; and at length, on the 20th September, he laid siege to the holy city. After fourteen days a breach was made in the walls, and ten banners of the prophet waved in triumph on the ramparts. A solemn procession was made by the Christians to the holy sepulchre to implore the Son of God to save his tomb and his inheritance from impious violation. Females cut off their hair and cast it to the winds (a common eastern token of distress), delicate ladies did penance by standing up to their necks in cold water placed on Mount Calvary. one of their writers, "would not listen to any prayer "But the Lord," says that they made; for the filth, the luxury and the adul

tery which prevailed in the city, did not suffer prayer or supplication to ascend before God."

The city was surrendered October 2d, 1187, and the Moslems rushed to the Temple in thousands. They defiled the holy places, and hurled down the cross from the pinnacle of the building. When every Christian had been removed from the vicinity of the Temple, Saladin went with great pomp to say his prayers in the Temple of the Lord," erected by the Caliph Omar. The Temple was consecrated anew to the service of God and Mahomet, and was abundantly purified with rose

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water.

Eleven important cities and castles of Palestine were delivered to Saladin as ransom for the King of Jerusalem, and the Grand Master of the Temple, and at the commencement of 1188, the latter was again at the head of the brethren of that order. All Christendom was aroused at the news of the capture of Jerusalem, and assistance in men and money were sent from Europe. A large body was thus once more assembled, and on the 4th October, 1189, they laid siege to Acre. Nine pitched battles were fought with various fortune, the Grand Master was slain, and to him succeeded the Knight Templar Brother Walter. He was also slain, and succeeded by Robert de Sablé. The Third Crusade having been preached in Europe by William of Tyre, the forcement in the arrival of the combined fleets of France Christian army at Tyre received a most valuable reinand England, and the presence of Philip Augustus and of the celebrated Richard Coeur de Lion. Six weeks after their arrival, the gates of Acre were thrown open to the warriors of the cross, and the Templars established themselves in what remained from thenceforth the chief house of their order. A most persevering and determined warfare was carried on between the forces of Saladin and the Christian army, and Coeur de Lion gained his full share of renown. The history of the brilliant deeds performed on both sides is a long and interesting one, but we have only to do with its final result, which was the formation of a treaty by which the Christians obtained once more the privilege of visiting Jerusalem as pilgrims, and Tyre, Acre, and Jaffa, with the intervening sea coast, were yielded to them.

Gilbert Horal succeeded Robert de Sablé as Grand Master of the Temple in 1195, and the latter was succeeded by Philip Duplessis in 1201. By the exertions of the Knights Templars and Hospitallers the Latin kingdom was preserved in Palestine after the departure of Richard Coeur de Lion for a period of ninetynine years. The individuals who next succeeded to the chief government of the Templars, were William de Chartres 1217, Peter de Montaigu 1218, Hermann de Perigord 1236. Some disastrous engagements took place in 1222, and 1236; but these were considered more than counterbalanced by the surrender of Jeru salem into the hands of the Christians, 1242.

Short, however, was the triumph of the followers of the cross. for a new and cruel enemy took away from them their sacred possession in 1244. The Carizmians from Tartary suddenly entered the Holy Land, and became the foes alike of Christians and Moslems. Under these circumstances the Templars and Mussulmen entered into a temporary alliance, and at length effected the destruction of their common enemy. In 1249 the Templars joined the forces of the French King, Louis IX. against Egypt, and captured Damietta. time William de Sonnac was Grand Master; and he was succeeded in 1252 by Reginald de Vichier.

At that

The military power of the orders of the Temple and Hospital, in Palestine, was at length completely broken by Bibars, fourth Mamlook Sultan of Egypt. Horrible excesses were committed by both parties in the course of the various conflicts.

In 1291, the Christian dominions in Palestine were reduced to within the narrow confines of the city of

Acre, and the Pilgrim's Castle, a strong fort of the Templars. These were at length invested, and the Grand Master William de Beaujeu took the command of the garrison. The old and feeble were sent away to the island of Cyprus, then the seat of the Latin kingdom, and none remained in the devoted city of Acre, but such as were prepared to suffer martyrdom rather than yield to the infidels. Military engines of the most formidable construction were set in operation by the besiegers: six hundred instruments of destruction were directed against the fortifications, and the battering machines were of such immense size and weight that a hundred wagons were required to transport the separate timbers of one of them. All the military contrivances which the skill of that age could produce were employed to facilitate the assault. After thirty-three days of constant fighting, the great tower or key of the fortifications was thrown down. At length the double wall was forced, and a body of Mamlooks penetrated to the centre of the city. The Knights drove them back with immense carnage, and precipitated their bodies from the walls. At length the number of the Templars was reduced to three hundred, and these fought their way to the strong Temple, at Acre, and shut themselves up. This little band was at length destroyed beneath the mins of their Temple, which the Sultan had caused to be undermined.

Thus fell the last stronghold of the Christians in Palestine, and with it every reasonable hope of recovering possession of the holy city. No sooner was this the case, than the remaining Templars scattered in different countries soon found their order falling into suspicion and neglect. They began to be considered as a useless body, whose large possessions in Europe might be much better, or at least more agreeably employed. A rancorous spirit was awakened among the clergy, who considered the exemptions and privileges of this order as so much detracted from their just rights. So high did this spirit rise among bishops, priests, and the whole body of the clergy, that the Roman pontiff had to express his grief and astonishment at the conduct of the ecclesiastics, and to threaten them with severe measures. And not only were the Templars obnoxious to the Church; they were also unpopular with the European sovereigns and nobles; in fact, they experienced such neglects, unkind suspicions and misrepresentataions, as commonly fall to the lot of those who cease, from whatever cause, to form the stepping-stones to the promotion of others. To join the Templars, at one period, was to rise to honour and renown in this world, and to obtain (as it was falsely believed) a passport to heaven: to succour them in adverse circumstances did not hold out any prospect of worldly advantage, and therefore the claims of mercy and forbearance were soon forgotten. But the Templars themselves were not free from blame: they interfered in the quarrels of different princes; became secular instead of religious warriors; and thus lost the popularity which attached to them as a holy order of men.

At length their ruin was resolved on by a needy and avaricious monarch, Philip the Fair, who longed to possess himself of a portion of their riches. He found an able accomplice in Pope Clement V., a man whose character is painted by Romish historians in the darkest colours. They prevailed on the Grand Master of the Temple to visit France in 1306, with a small retinue, under the pretence of consulting him on measures relative to the recovery of the Holy Land; while secret agents were at work circulating dark rumours respecting the order, and at length the Templars were openly charged with abominable crimes. Upon this, Philip arrested the members of the order and seized on their real and personal property. The accusations were both absurd and horrible; of the former description were those which charged them With worshipping an idol covered with an old skin havng the appearance of a piece of polished oil-clotn, with

carbuncles for eyes, bright as the brightness of heaven; also with burning the bodies of deceased brethren and making the ashes into a powder which they administered to the younger brethren in their food, &c., &c.

The tortures practised on this devoted order, in the hope of getting them in the midst of their agonies to confess to these unjust accusations, were of the most revolting description, and ended in death or madness of numbers; but for a long time they were to no purpose. At length forged letters were produced as if from their superior, the Grand Master, exhorting them to do as their persecutors wished, and under this decception several gave way, and made pretended confessions, whose very improbability destroyed the effect intended to be produced by them. And now a similar scene was to be enacted in England. The accusations were opened against them at the episcopal hall, London, after the most industrious endeavours on the part of the Pope's inquisitors, to substantiate some charge, and after many months' imprisonment of the Templars. These venerable men, after all the hardships and dangers of their past lives, were now degraded and tortured by those who had extolled them to the skies; they had to answer to the most absurd allegations, and to choose suffering of the most dreadful kind, or make a false confession. Nothing could be extorted from them, and after another long season of imprisonment they were called before a second council in 1310. They had been subjected to three years of imprisonment and varied sufferings; torturė had been skilfully applied by French monks, but, as it had been enacted, "without the mutilation or disabling of any limb, and without a violent effusion of blood;' (truly, "the tender mercies of the wicked are cruel;") the Templars knew that by pronouncing a few words of confession they should immediately receive absolution from the Church, and be restored to pardon, peace, and liberty, yet not one of them would depart from the truth, and at the second council they made, instead of a confession, a noble declaration of faith and of their innocency, most unpalatable to the assembled ecclesiastics. Fresh atrocities were then resorted to, and the prisons of the Tower, Aldgate, Ludgate, Newgate, Bishopsgate, and Cripplegate, were the scenes of renewed tortures. At length the constancy of two poor serving brethren was overcome, and their confessions were triumphantly published. An avowal of guilt was also wrung from the chaplain of the order. But the progress made in this way was so slow, that the accusers changed their ground, and endeavoured to convince the Templars of their guilt, in having at former periods received absolution at the hands of the Master, he being a layman. The Templars did not attempt to defend themselves from this charge, and were willing publicly to confess their error in that respect. A sort of compromise was therefore entered into; the Templars made their confession in Latin or Norman French; they were pardoned, and the impression produced on the public mind by their. having made a confession of guilt was sufficient for the purpose of the ecclesiastics.

Their order was now suppressed by the Pope, and their treasures appropriated by the pontiff and the European sovereigns. Their lands were subsequently given to the Knights Hospitallers, but not till enormous claims on the part of the French king and others had been satisfied. The stipend allowed to the surviving Templars was fourpence a day, and this was so irregularly paid that some of them were near dying of hunger, until charity was in some measure awakened on their behalf. Some of them joined the world once more, and presumed to marry, which gave great offence to the Pope, who ordered them to be separated from their wives. It is remarked by historians respecting those who were foremost in the horrid cruelties practised on the Knights. Templars, that every one came to a miserable and untimely end.

A PAIR OF SPECTACLES.

THE ROUND CHURCH AT LITTLE MAPLESTEAD,
ESSEX.

This edifice, in the opinion of Mr. Rickman, affords the latest specimen of the circular churches. The plan of the building may be considered unique, with its circular portion at the west, and a semicircular chancel. The latter peculiarity is considered, in general, to indicate a Saxon origin; but there are no marks in the church at Little Maplestead of the Anglo-Saxon style of architecture. Mr. Britton judges, from the style of the windows, arches, doorways, &c., in the absence of document, that the erection of the church may be referred to some period between or during the reigns of King John and Henry the Third, both of whom appear to have granted the Knights at Maplestead some privileges. The establishment at Maplestead just alluded to, was that of the Knights Hospitallers, to whom the whole parish, with all its appurtenances, was presented in 1186. They established a preceptory there, under the appellation of Le Hospital, which rapidly increased in wealth and importance, and in less than two centuries received donations from more than seven hundred benefactors in Essex and the adjoining counties. This small and ancient edifice, though much dilapidated, has still a pleasing appearance, and internally possesses a considerable degree of elegance. The principal entrance is at the west end by a porch with three doors; this immediately introduces us into the circular part, which measures thirty feet in diameter, and has a peristyle, consisting of six clustered columns, supporting pointed arches; the whole length of the church is seventy feet. This edifice, is dedicated to St. John, as were most of the churches erected by the Knights Hospitallers.

At the presentation of the parish to that order, there was a church existing at Little Maplestead; but not the present edifice. "The retention of the Norman font," it has been remarked, "at the time of rebuilding the church, is a clear proof that this building (whatever might have been the case in other instances,) was never used for the purposes of baptismal immersion."

Unfortunately a school-room has been erected at the west end of the church, forming a most "unseemly excrescence," and completely concealing the beautiful doorway. The removal of this ill-judged addition would greatly improve the appearance of the church, and would also save the ornaments of the doorway from undergoing an obliterating process by whitewashing, which it now receives when the operation becomes necessary for the school-room. The following just remarks on these injudicious cleansings of our ancient churches, we extract from WALLEN'S History of Little Maplestead Church. Dr. Franklin, in one of his essays, gives a ludicrous account of the annual whitewashings to which the houses are subjected in America, where the ladies turn their liege lords out of house and home, in order they that may indulge in their favourite propensity.

Although this mania has not seized the ladies of our own country, it seems to be making rapid strides among those of the other sex, who are officially connected with our churches and cathedrals. Nothing is more common in entering such buildings, than to notice alternate streaks of yellow, black, and white, introduced to distinguish the various mouldings of the clustered pillars; and not unfrequently the grotesque heads, introduced as corbels to support the roof, are made, by the assistance of the village painter, to look smilingly and contentedly under the superincument weight.

This beautifying may please the vulgar, but it entirely removes the venerable aspect so impressively assumed by mouldering stone. The awe-inspiring grandeur of our cathedrals and churches, creates an instinctive feeling of their age and connexion with by-gone days; but no sooner has the brush of the "improver" been passed over the graceful and delicate enrichments which characterize the Gothic style of architecture, than that sombre effect, which produces so powerful an impression upon the mind, is entirely destroyed.

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CHINESE WEARING SPECTACLES OF ROCK CRYSTAL

EVERY one is familiar with the appearance of a pair of spectacles; but it is not generally known, except to those who are unfortunate enough to require their aid, that young persons who wear spectacles do so from a reason totally opposite to that which influences older persons. It is true that an imperfection of sight is the motive in both cases; but this imperfection proceeds from two opposite causes, which we will endeavour to explain. In order that the eye may convey to the mind a correct picture of an external object, it is essential that the rays of light which proceed from that object should converge to a focus exactly at the retina. If the focalization takes place either a little in front, or a little behind the retina, imperfect vision is the result. As the rays are converged by the crystalline lens, in the front part of the eye, and as convergence of this kind differs in degree in proportion to the curvature of the lens, the eye is so formed by nature that the convergence shall exactly bring the rays to a focus at the retina. Here, however, is an important addition. All distant objects send rays which converge sooner behind the crystalline lens, than those which emanate from near objects; and therefore a rigorous maintenance of the relative positions and conditions of the different parts of the eye would render it impossible for all the rays to focalize exactly at the retina. There is, however, an admirable adjusting mechanism in the eye, whereby when we look at a distant object, the crystalline lens is in such a position as to focalize the rays at the retina; and when we look at a near object, some kind of adjustment takes place whereby the refracting mechanism of the eye is adapted to the altered state of things, and the focalization still occurs at the retina. What the nature of this adjustment may be, has never yet been satisfactorily determined. Some philosophers think that the length of the eye, from front to back, is susceptible of change; some think that the cornea, or front of the eye, changes its curvature, or that the pupil varies in diameter; others attribute the adjustment to a change in the shape be the cause, there is abundant proof of the existence in or position of the crystalline lens, or both. But whatever a healthy eye, of a power of adjustment to suit objects at different distances from the eye.

Now in off-sighted and near-sighted persons this power of adjustment is imperfectly developed. The cornea, the lens, the retina, all may be, individually, fitted for the process of distinct vision: but there are ing that vision to different distances, limited and impersome circumstances which render the power of adjustfect. One person, for example, although he can see objects with perfect distinctness a distance of a few inches, sees all distant objects enveloped in a kind of haze or mist; his sight may not be bad, but be limited in its power of adjustment to different distances. Another person may be utterly unable, by the unassisted eye, to read small print, for want of the power to adjust the eye to small distances, and from the small angle under which the letters of a book are seen when held at a

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