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to make astronomical observations in the island of ment. This caution has been carefully attended to in Cayenne, which is not quite 5° north of the equator. the matter we are discussing, by the measurement Sir Isaac Newton has, in his Principia, described the and comparison of degrees at various parts of the particulars of the discovery. He says, that when earth's surface. Ritcher was, in the month of August, observing the In the measurement of a degree or of an arc of a transits of the fixed stars over the meridian, he found meridian, many difficulties present themselves in the his clock to go slower than it ought, in respect of the way of an actual and mechanical measurement. The mean motion of the sun, at the rate of 2' 28" a day. general features of a country are such as to make any Therefore, setting up a simple pendulum to vibrate in attempt of this kind unadvisable; a great number of seconds, which were measured by an excellent clock, almost conjectural allowances must be admitted into he observed the length of that simple pendulum; and such a plan of operations, which forbid our placing this he did over and over every week for ten months much confidence in the result. The first modern together; and upon his return to France, comparing measurement, having any just claim to accuracy, was, the length of that pendulum with the length of the however, made in this manner. This was the meapendulum beating seconds at Paris, he found it shorter surement by Norwood, in 1635. The arc measured by 14 line. In accounting for this difference in the was that part of the meridian which lies between length of the two pendulums, Newton allowed th of London and York. The difference of the latitudes of a line as the utmost that could be attributed to the ex- these cities was first ascertained; this gave the numtension of the pendulum by the heat of the climate; ber of degrees in the arc to be measured; the distance the difference, or 1 line by which this pendulum between the two cities was then actually measured; was shorter than the Paris one, was made necessary and the turnings and windings of the road, and the by the less gravity of bodies at and near the equator. ascents and descents, were allowed for afterwards. From this fact he obtained the same conclusions he The length of a degree thus determined was 122,399 had before deduced from theory alone, namely, that English yards; which, notwithstanding the extreme the equatorial diameter of the earth was greater than liability of this method to errour, is not very far from the polar by the 229th part of the whole diameter. the truth; according to the latest determinations, the Since that time observations upon the lengths of pen-length of a degree between these latitudes is 121,660 dulums beating seconds in different latitudes, have yards. The only other instance of the actual meabeen made with great assiduity by scientifick men of surement of an arc of the meridian is that of Messrs. all countries; but recent experiments tend to show that the earth's ellipticity is not so great as the fraction is the value which results from the latest investigations.

LENGTH AND MEASUREMENT OF DEGREES UPON

THE EARTH'S SURFACE.

The remaining evidence of the earth's ellipticity is the different lengths of degrees of the meridian arc in different latitudes.

Mason and Dixon. They measured an arc of the meridian of 179,359,313 English yards in length, in the state of Pennsylvania. An account of this measureIment is given in the Philosophical Transactions for the year 1768. The other and more accurate mode of actual measurement and of trigonometrical calculations finding the length of a degree, is a combination of founded upon it. All geodesical* operations (as they are called) are now conducted according to this method. Two places are selected, which lie under the same meridian, or nearly so; the difference of their A degree of a meridian is that portion of it which latitudes, which gives the number of degrees in the must be travelled over, in order to change the altitude arc to be measured, is then ascertained with the utmost of any particular star, by the 360th part of the imagi- precision. A base line of a few miles in extent, and nary meridian circle in the heavens: if the spaces at some little distance from the meridian arc, is then travelled over in different parts of the same terrestrial very carefully measured; this is the only actual meameridian, in order to produce this change in the alti-surement which need be made. The extremities of tude of a star, be not equal to one another, the terres- this base line are connected with the extremities of the trial meridian cannot have the same curvature in every part, and is therefore not a circle; and consequently, the figure of the earth on the surface of which the meridian is traced cannot be a perfect sphere. Now it has been found by trial, that to raise the pole star by a quantity equal to a celestial degree, an observer must travel over a greater and increasing space as he proceeds from the equator to the poie. Hence it follows, that the degrees of a meridian line on the earth, or degrees of latitude, gradually increase from the equator to the pole; the meridian has, therefore, less curvature at the poles than at the equator, and the earth upon which it is traced is not a perfect sphere, but is flattened at the poles.

It is not to be immediately concluded from this that the earth is a regular oblate-spheroid; but it has been justly remarked, that, though it is only by experiment that the true figure of the meridian can be discovered, it has been found necessary to assume hypothetically (or by way of supposition,) that its figure is the curve next in simplicity to the circle, viz. the ellipse, and also to suppose that the earth is a spheroid generated by the revolution of this ellipse about its shorter axis; for, in many complex cases, this mode of getting near the truth by probable suppositions, has been found the simplest and most convenient to be pursued; the only caution to be observed, is to submit the supposition first made to the test and correction of actual experi* A line is a small French measure equal to the twelfth part of an inch.

meridian arc, by imaginary triangles; the sides of which are not measured, but, by the aid of the base line, and by means of the angles of the triangles, which are all ascertained by an instrument for measuring angles, are determined by trigonometrical computation. This mode of ascertaining the length of the meridian will, however, be set in a clearer light by following the steps of the process in the subjoined figure.

Let M m represent a meridian arc; the difference of latitudes of the two extremities, M and m, being found, the length of a degree in the latitude of M and m will be the length of the whole arc divided by the number of degrees contained in it.

A level plain is then to be selected, on which a base line A B is measured; the two extremities of this line are to be connected with the two extremities of the arc Mm, by a series of triangles. For this purpose convenient stations are fixed upon, such that the three stations situate in the three angles of every triangle may be visible to each other. Let C, D, E, be the stations fixed upon, these are supposed to be connected together, and with the points M, m, by the imaginary lines which form the various triangles ABC, BC m, ACD, CDE, and DEM. Then the angles by which the two stations C and B, appear to be separated from each other when viewed from the station A, is observed. This observation gives the angle C A B of the triangle

* From two Greek words, which combined, signify a dividing or apportioning of the earth.

ABC; the other angles of this triangle are observed The following particulars will show at once the acand determined in the same manner, and the side A B,curacy which now distinguishes geodesical operations, which is the base line, being known from measurement, and some of the means taken to ensure it:

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the other two sides A C, BC, may be computed by plane trigonometry. By this means we obtain a side of each of the triangles B Cm, ACD, and are enabled to continue the process without measuring any more sides. The angles of these triangles are measured as in the case of the first, and their sides are ascertained in like manner by trigonometry; and by proceeding in a similar way in the resolution of the whole series of triangles, the sides and angles of all are determined. The remaining step in the field proceedings is to ascertain the inclination of the lines MD and Bm, to the meridian are; astronomy affords the means of doing this. From the data furnished by these operations, the length of the arc M m is determined in the following manner :-from M and D, draw the lines Ma perpendicular to Da, parallel with the meridian line, meeting each other in a; Db, A b, A c, Bc, md, Bd, are also drawn so as to be respectively perpendicular to and parallel with the meridian. Then it is evident that the length of M m is equal to the sum of the lengths of a D, b A, cB, Bd, which are found thus the inclination of M D to the meridian having been already determined by an astronomical observation, the angle D M a in the right-angled triangle D M a is known from it, and the side M D is also known, so that Da (which is equal to MDX sin. D M a) may at once be computed by trigonometrical tables. In a similar manner the sides b A, c B, d B are computed, and the sum of the whole gives the length of the meridian arc Mm, and the length of a degree is the length of the whole arc divided by the number of degrees contained in it.

The first base in the English measurement, of which the result is given in the above table of degrees, was about five miles in length, and was measured upon Hounslow-heath with a steel chain of exquisite workmanship. The same base had been measured three years before by General Roy, with glass rods, and the two measurements (in a length of five miles) differed only 24 inches. The French base was measured with rods of platina, that in Lapland with rods of iron, and an allowance was made for the changes of temperature affecting the length of the rods in the course of the operation. In a previous measurement in Lapland, the French astronomers, in order to guard against the extreme contracting effect of cold upon metals, employed rods of deal; this was the more necessary in that measurement, as it was performed in the depth of winter, and the frozen surface of a river was selected for the base line, with a view to obtain as level a plain as possible. It is usual also, in order to prove the correctness of the geodesical process, to measure, towards the conclusion, what is called a base of verification. We have already stated that all the sides of the series. of triangles (with the exception of the base line A B, which is a side in the first triangle) are not measured but computed: to verify all the previous steps in the process, the length of one of the sides of the triangles, as it has been deduced from computation, is compared with its length determined by actual measurement. The side of the triangle thus measured is called a base of verification, and is taken as far distant from the first base as circumstances will admit. In the French operations the base of verification was distant between four and five hundred miles from the first base, and was 7 miles in length, and yet the difference between its computed length and that obtained from its actual measurement did not amount to twelve inches.

From an inspection of the table before given, it appears that the length of a degree from the equator to the pole increases-the curvature therefore diminishes, and the earth is not a sphere but is flattened at the poles, and the polar diameter is less than the equatorial; and although the various modern measurements may not, on a comparison one with another, agree in giving to the difference of the two diameters precisely the same value, yet they all ascertain the fact of the polar diameter being less than the equatorial, and that a degree increases towards the poles; and this establishes the oblate spheroidal figure of the earth.

The value of the compression or the fraction expressing the difference between the two diameters, as deduced from a comparison of the lengths of a meridional degree in different latitudes, determined by the Picard was the first person who measured an arc of most approved measurements, has been lately shown the meridian by this method. The operation was per- by Professor Airy, in a paper in the last volume of the formed in the year 1670; the arc commenced near Philosophical Transactions to be, that is, the Paris, and extended northward; the result of the mea-polar diameter is less than the equatorial by the 278.6th surement gave, as the length of a degree in latitude part of the whole diameter. 491, 121,627 yards, which differs only 35 yards from what is now considered as the most exact length; an accuracy which is justly supposed to be quite accidental.

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Operations are now being carried on, on the conti nent, which have for their object the more precise determination of the fraction of ellipticity, and of the compression of the earth. The measurement of an arc of the parallel of latitude 45°, of 15° or 16° in extent has been already accomplished. One extremity of this arc is at Marennes, on the west coast of France, and a little to the north of the Garonne, and traversing France, Piedmont, and the northern parts of Italy, its other extremity is at Fiume, in the Austrian dominions, and on the eastern shores of the Adriatic. The value of the ellipticity as deduced from these operations is We have already stated that the pendulum experiments give. This similarity in the results afforded by such very different kinds of investigation is a strong argument in favour of the general correct ness of both.

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The mean degree of a meridian or the degree the length of which is as much greater than that of a degree at the equator, as it is less than that of a degree at the poles, is in latitude 45°, which is the mean latitude between the equator and the poles. Its length, according to the French measurement, is 60759.4 fathoms, or 12158.8 yards. The circumference of the elliptick meridian is found by multiplying the mean degree by 360, and is equal to 24855.84 miles. The circumference of the equator is 24896.16 miles, and is not quite 41 miles longer than the elliptick meridian. The French measurement, in 1792, was undertaken with a view to obtain a standard measure of length, to serve as the basis of a new system of weights and measures, According to this new system, the unit, or first element of linear measure, is called a metre; and the metre was declared to be equal to the ten millionth part of the quadrant of the meridian-which is a fixed and unalterable quantity in nature. The quadrant of the meridian was by this measurement found to be 5,130,740 toises, or 10,936,578 English yards: the French metre, or the ten millionth part of this quantity, would accordingly be 1.093578 yards, or 39.37 inches, nearly. This method of obtaining a standard of measure is not, perhaps, so good as that which consists in observing the length of the pendulum, which, in a certain latitude, beats seconds of mean time. For the length of this pendulum is ultimately ascertained by a reference to the equable motion of the earth upon her axis, and is, therefore, ascertainable without the aid and use of any linear measure whatever; whereas, in the very act of determining the French standard, or the quadrant of the meridian, some linear measure already in use must be employed; and thus the very basis of their new system is expressed in terms of that in the place of which it is substituted.

The importance of possessing the true length of a degree of the meridian, is not confined to investigations having for their object the determination of the figure of the earth. Upon the simple fact of the length of a degree, seemed to depend the overthrow or establishment of the theory of Universal Gravitation. The particulars connected with the discovery of a principle productive of such various effects in nature, is not the less interesting that it illustrates the secret dependency of parts of science apparently the most distinct, and the assistance which each in its place is calculated to afford the rest.

The corner-stone of the whole system of Universal Gravitation is, that the force which causes a heavy body to descend to the surface of the earth, is the same that retains the moon in her orbit, and makes her defleet from a straight line, or bend towards the earth. All that was requisite to establish the identity of the forces by which these two effects were produced, was to prove, that the quantity of effect produced in a certain time upon the moon in thus deflecting from a straight line, (taking into consideration the law by which the force varied, and the distance of the moon,) was in due proportion to the effect produced by the force of gravity, in the same time, upon a falling body at the surface of the earth. It is evident, therefore, that the determination of this question depended upon, and would in its solution be affected by, the distance of the moon from the earth. This distance being expressed only in a number of radii of the earth (about 60,) it was necessary to ascertain the length of the earth's radius. This could only be done by means of the proportion which the radius of a circle always bears to the circumference; and the length of the circumference being 360 times that of a degree, the whole matter at last resolved itself into the geodesical operation of accurately measuring a degree upon the earth's surface. The only measure which in 1666, the time of Newton's first taking up the subject, was in existence, was that of Norwood's: this exceeded the true length of a degree by little less than 1000 yards;

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and as this errour would be greatly multiplied in each step of the process, it is not surprising that Newton, whether he used this measure, or the still more incorrect one of 60 miles to a degree, could not reconcile the two phenomena of the falling stone and the revolving moon, so as to refer both to the same causenamely, the attractive force of the earth. The consequence of this errour in the then received length of a degree was, that for many years Newton laid aside his theory of universal gravitation. But in 1670, the measurement of an arc of the meridian, by Picard, took place; by mere accident the length of a degree, in latitude 49, was then ascertained to be within 35 yards of what is now considered the true length. This new measure brought Newton back to his favourite hypothesis. He then satisfactorily proved, that the force of gravity, and the force by which the moon is retained in her orbit, are one and the same. It is related, that towards the end of the calculation, and when he perceived its probable successful issue, he became so much agitated, as to be obliged to request a friend to assist him in completing it. Thus, by the aid of the true length of a degree, was finally established the grand theory of Universal Gravitation.

(From the Philadelphian.)

SONG OF 300,000 DRUNKARDS IN THE UNITED
STATES.

We come, we come with sad array,
And in procession long,

To join the army of the lost,
Three hundred thousand strong.

Our banners beck'ning on to death,
Abroad we have unrolled;
And Famine, Care, and wan Despair
Are seen upon their fold.

Ye heard what musick cheers us on,-
The mother's cry that rang
So wildly, and the babe that wailed
Above the trumpet's clang.

We've taken spoil; and blighted joys
And ruined homes are here;
We've trampled on the throbbing heart
And flouted sorrow's tear.

We come, we come-we've searched the land.
The rich and poor are ours,
Enlisted from the shrines of God,
From hovels and from towers.

And who or what shall balk the brave
That swear to drink and die?
What boots to such, man's muttered curse
Or His, that spans the sky?

Onward! though ever on our march
Hang misery's countless train;
Onward for hell-from rank to rank
Pass we the cup again!

We come of the world's scourges, who
Like us have overthrown?
What wo had ever earth like wo
To our stern prowess known!

We come, we come to fill our graves.
On which shall shine no star;
To glut the worm that never dies,
Hurrah! hurrah! hurrah!

W. B. T.

One of the enormities of Protestantism, which shocks the Papists, is the marrying of our Clergy. What is to be said of the Roman Catholick Bishop England, who, going on a foreign mission, takes out with him four nuns ?-

The English Bishop takes one wife,
The Papist says, "O fie!"

The Roman Catholick takes out four,
And no man asks him, why?

olick sub-editor, he begs leave to offer an explanation of the
Having shown this sprightly contribution to our Roman Cath-
seeming inconsistency:
:-

To vindicate the Papist's life,
See how the thing is done;
The Protestant alone takes wife,
The Catholick takes nun.

Albion.

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This stupendous wall, which extends across the northern boundary of the Chinese empire, is deservedly ranked among the grandest labours of art. It is conducted over the summits of high mountains, several of which have an elevation of not less than 5225 feet, (nearly a mile,) across deep valleys, and over wide rivers, by means of arches: in many parts it is doubled or trebled, to command important passes; and at the distance of nearly every hundred yards is a tower or massive bastion. Its extent is computed at fifteen hundred miles; but in some parts, where less danger is apprehended, it is not equaliy strong or complete, and towards the north-west, consists merely of a strong rampart of earth. Near Koopekoo it is twenty-five feet in height, and at the top about fifteen feet thick: some of the towers, which are square, are fortyeight feet high, and about forty feet in width. The stone employed in the foundations, angles, &c. is a strong gray granite; but the materials for the greater part consist of bluish bricks, and the mortar is remarkably pure and white.

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The strange trials to which those suspected of guilt were put in the middle ages, conducted with many devout ceremonies, by the ministers of religion, were pronounced to be the judgements of God! The ordeal consisted of various kinds : walking blindfold amidst burning ploughshares; passing through fires; holding in the hand a red hot bar; and plunging the arm into The area of the construction of this great barrier, boiling water the popular affirmation,-'I will put which has been and will continue to be the wonder my hand in the fire to confirm this,' appears to be and admiration of ages, is considered by Sir George derived from this solemn custom of our rude ancestors. Staunton as having been absolutely ascertained; and Challenging the accuser to single combat, when frehe asserts that it has existed for two thousand years. quently the stoutest champion was allowed to supply In this assertion he appears to have followed Du their place; swallowing a morsel of consecrated bread; Halde, who informs us that "this prodigious work was sinking or swimming in a river for witchcraft; or stretchconstructed two hundred and fifteen years before the ing out the arms before the cross, till the champion soonest birth of Christ, by order of the first Emperor of the wearied dropped his arms, and lost his estate, which family of Tsin, to protect three large provinces from was decided by this very short chancery suit, called the eruptions of the Tartars." However, in the His- the judicium crucis. The bishop of Paris and the tory of China, contained in his first volume, he as- abbot of St. Dennis disputed about the patronage of a cribes this erection to the second Emperor of the dy-monastery: Pepin the short, not being able to decide nasty of Tsin, named Chi Hoang Ti; and the date immediately preceding the narrative of this construction is the year 137 before the birth of Christ. Hence suspicions may arise, not only concerning the epoch when this work was undertaken, but also relatively to VOL. II.

43

on their confused claims, decreed one of these judgments of God, that of the cross. The bishop and abbot each chose a man, and both the men appeared in the chapel, where they stretched out their arms in the form of a cross. The spectators, more devout than

the mob of the present day. but still the mob, were piously attentive, but betted however now for one man, now for the other, and critically watched the slightest motion of the arms. The bishop's man was first tired: -he let his arms fall, and ruined his patron's cause forever! Though sometimes these trials might be eluded by the artifice of the priest, numerous were the innocent victims who unquestionably suffered in these superstitious practices.

From the tenth to the twelfth century they were very common. Hildebert, bishop of Mans, being accused of high treason by our William Rufus, was preparing to undergo one of these trials; when Ives, bishop of Chartres, convinced him that they were against the canons of the constitutions of the church, and adds, that in this manner Innocentiam defendere, est innocentium perdere.

An abbot of St. Aubin of Angers in 1066, having refused to present a horse to the Viscount of Tours, which the viscount claimed in right of his lordship, whenever an abbot first took possession of that abbey: the ecclesiastick offered to justify himself by the trial of the ordeal, or by duel, for which he proposed to furnish a man. The viscount at first agreed to the duel; but, reflecting that these combats, though sanctioned by the church, depended wholly on the skill or vigour of the adversary, and could therefore afford no substantial proof of the equity of his claim, he proposed to compromise the matter in a manner which strongly characterizes the times: he waived his claim, on condition that the abbot should not forget to mention in his prayers, himself, his wife, and his brothers! As the orisons appeared to the abbot, in comparison with the horse, of little or no value, he accepted the proposal.

in this case the assailant is the more terrible combatant.

In these times those who were accused of robbery were put to trial by a piece of barley-bread, on which the mass had been said; and if they could not swallow it they were declared guilty. This mode of trial was improved by adding to the bread a slice of cheese; and such were their credulity and firm dependance on Heaven in these ridiculous trials, that they were very particular in this holy bread and cheese called the corsned. The bread was to be of unleavened barley, and the cheese made of ewe's milk in the month of May.

Du Cange observed, that the expression—' May this piece of bread choke me!' comes from this custom. The anecdote of Earl Godwin's death by swallowing a piece of bread, in making this asseveration, is recorded in our history. If it be true, it was a singular misfortune.

Amongst the proofs of guilt in superstitious ages was that of the bleeding of a corpse. If a person was murdered, it was believed that at the touch or approach of the murderer the blood gushed out of the body, in various parts. By the side of the bier, if the slightest change was observable in the eyes, the mouth, feet, or hands of the corpse, the murderer was conjectured to be present, and many innocent spectators must have suffered death; for when a body is full of blood, warmed by a sudden external heat and a putrefaction coming on, some of the blood-vessels will burst, as they will all in time.' This practice was once allowed in England, and is still looked on in some of the uncivilized parts of these kingdoins as a detection of the criminal. It forms a rich picture in the imagination of our old writers; and their histories and ballads are laboured into pathos by dwelling on this phenomenon.

In the tenth century the right of representation was not fixed it was a question, whether the sons of a son ought to be reckoned among the children of the family; Robertson observes that all these absurd institutions and succeeded equally with their uncles, if their fathers were cherished from the superstitious of the age believhappened to die while their grandfathers survived. ing the legendary histories of those saints, who crowd This point was decided by one of these combats. The and disgrace the Roman calendar. These fabulous champion in behalf of the right of children to represent miracles had been declared authentick by the bulls of their deceased father proved victorious. It was then the popes and the decrees of councils; they were greedestablished by a perpetual decree that they should hence-ily swallowed by the populace; and whoever believed forward share in the inheritance, together with their that the Supreme Being had interposed miraculously on uncles. In the eleventh century the same mode was those trivial occasions mentioned in legends, could practised to decide respecting two rival Liturgies! A not but expect his intervention in matters of greater pair of knights, clad in complete armour, were the importance when solemnly referred to his decision. criticks to decide which was the authentick and true Besides this ingenious remark, the fact is, that these Liturgy. customs were a substitute for written laws which that barbarous period had not; and as no society can exist without laws, the ignorance of the people had recourse to these customs, which, bad and absurd as they were, served to close controversies which otherwise might have given birth to more destructive practices. Ordeals are in truth the rude laws of a barbarous people who have not yet obtained a written code, and not advanced enough in civilization to enter into the refined inquiries, the subtile distinctions and elaborate investigations, which a court of law demands.

If two neighbours, say the capitularies of Dagobert, dispute respecting the boundaries of their possessions, let a piece of turf of the contested land be dug up by the judge, and brought by him into the court, and the two parties shall touch it with the points of their swords, calling on God as a witness of their claims;-after this let them combat, and let victory decide on their rights!

In Germany, a solemn circumstance was practised in these judicial combats. In the midst of the lists, they placed a bier. By its side stood the accuser and the accused; one at the head and the other at the foot of the bier, and leaned there for some time in profound silence, before they began the combat.

May we suppose that these ordeals owe their origin to that one of Moses, called the Waters of Jealousy?" The Greeks likewise had ordeals, for in the Antigonus of Sophocles, the soldiers offer to prove their innocence Judicial combat appears to have been practised by by handling red-hot iron, and walking between fires. the Jews. Whenever the rabbins had to decide on a One cannot but smile at the whimsical ordeals of the dispute about property between two parties, neither of Siamese. Among other practices to discover the juswhich could produce evidence to substantiate his claim, tice of a cause, civil or criminal, they are particularly they terminated it by single combat. The rabbins were attached to using certain consecrated purgative pills, impressed by a notion that consciousness of right would which they make the contending parties swallow. He give additional confidence and strength to the rightful who retains them longest gains his cause! The pracpossessor. This appears in the recent sermon of a tice of giving Indians a consecrated grain of rice to rabbin. It may, however, be more philosophical to swallow is known to discover the thief, in any comobserve that such judicial combats were more frequent-pany, by the contortions and dismay evident on the ly favourable to the criminal than to the innocent, because the bold wicked man is usually more ferocious and hardy than he whom he singles out as his victim, and who only wishes to preserve his own quiet enjoyments

countenance of the real thief.

But to return to the middle ages. They were acquainted in those times with secrets to pass unhurt these singular trials. Voltaire mentions one for under

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