Pays Tribute unto thee: Rome's conquering band,
More vanquished nations under her command
Never reduced; glad Berecynthia so
Among her deathless progeny did go :

A wreath of flowers adorned her reverend head,
Mother of all that on Ambrosia fed.

Thy god-like-race must sway the world to come.——
Would these commanders of mankind obey
Their honoured parent, all pretences lay
Down at your royal feet, compose their jars,
And on the growing Turk discharge their wars;

The Christian knights that sacred tomb should wrest,
From Pagan hands, and triumph o'er the East.
Our England's Prince, and Gallia's Dolphin might
Like young Rinaldo and Tancredi fight;

In single combats by their swords again The proud Argantes and fiere Soldan slain; Again might we their valiant deeds recite, And with your Tuscan muse exalt the fight. But Waller's poetry was not the weapon that would protect her from political troubles. The English court being Protestant, and the Queen Henrietta Maria, Roman Catholic, there had been a good deal of strong feeling spread abroad; and now that Mary arrived, it was not long before she was regarded with distrust. The mob surrounded her palace, and demanded the dismissal of her priests. She appealed to Charles, and Charles referred her to the parliament and the Earl of Dorset, Lord Lieutenant of Middlesex, was ordered to send her a guard of a hundred men.

She continued in England under very unpleasant circumstances until 1641, when a petition was presented to parliament, to desire the two houses to join in an address to the king, to hasten her departure out of the kingdom. This was done; and parliament voted her ten thousand pounds to quicken her departure. After an unsuccessful application to her son-in-law, the king of Spain, to permit her either to return to the Netherlands (which then belonged to him), or to pass through them to Holland, she retired to Cologne. Charles caused her to be accompanied as far as Holland by the Earl of Arundel, and gave her ten thousand pounds for travelling charges.

At Cologne she died on the following year, 1642, in great wretchedness, neglected by nearly all the courts to whom she was so nearly related. Her great enemy, Richelieu, survived her about five months.

HIGH minds of native pride and force
Most deeply feel thy pangs, Remorse!
Fear for their scourge mean villains have;
Thou art the torturer of the brave!

SIR WALTER SCOTT.

THERE is a calm the poor in spirit know,
That softens sorrow, and that sweetens woe;
There is a peace that dwells within the breast
When all without is stormy and distrest;
There is a light that gilds the darkest hour,
When dangers thicken, and when tempests lour.
That calm to faith, and hope, and love is given,
That peace remains when all beside is riven,
That light shines down to man direct from heaven!
EDMESTON.

E'EN as the dew-drops and the genial rain
Enrich and fertilize the sterile plain;
Cause it the kindly fruits of earth to yield,
And with a plenteous harvest crown the field;
So does the Gospel pour into each heart
1ts truths Divine, its influence impart :
Softens the stony hearts to hearts of flesh,
Meet to produce the fruits of righteousness.
Promote we then the knowledge of the Lord
And promulgate the Gospel truths abroad,
Till from the north to south, from east to west,
Jehovah's praise is sung, His name for ever blest.-H.A.

SOCIALISM.

THERE is no trait in the character of human nature more deplorable than the easiness with which it can be imposed upon by the fallacious zeal of knaves or madmen; and the more so, when we reflect that this failing arises from the perversion of one of its most beautiful endowments, namely, its yearning after the perfect and the true. Man is betrayed by his own eager thirst to every mirage that rises before him in his wanderings through the weary and uncertain ways of this mysterious life. But in most instances, not only a too ready credulity, but a somewhat perverse disposition in the nature of that credulity, is to be lamented, and it is sad to observe that the wilder and more noxious the meteor that attracts him, the more earnest and the more fatal his pursuit. No doctrine whatsoever, so dangerous, so inconsistent, so absurd, as not to boast its apostles and followers; and tenets and opinions, which characterize madness or monomania in the individual, become in the notions of the uncertain vulgar, a new light, a glorious dispensation. The tendencies of all animated nature around us, are wholesome and beneficent: it is for man alone, with his lofty boast of freewill, even in his pursuit of higher and better things, to follow too often and too blindly the mischievous and the false.

There is, in these days especially, a lofty and somewhat arrogant assumption of superiority. The schoolmaster has been abroad-intelligence is diffused— intellect no longer feels its way with wholesome and necessary caution, it vaults in these ambitious days, and like ambition "o'erleaps itself." The world, forsooth, is altogether wiser than it has been; and yet these are the days in which the opinions of a man can gain ground, whom our ancestors would have secured and whipt, as plainly and confessedly a sore rogue and itinerant corrupter of good sense and morality. Wild ridiculous fanatics, together with their miserable victims, disfigure many a page of our goodly history, but most, if not all, knew better than to attack the time-founded institutions of their country; these have ever been more spiritual enthusiasts than temporal rascals, not less crack brained but more honest.

These Owenites form a sect whose object is to introduce a specious generalization of larceny, and an universal libertinism into the health of their country; one man endeavouring to substitute his crude nostrum for the results of all the wisdom and experience of the past, the fruit of the common sense and intelligence of every age, confirmed and hallowed by the great teacher, Time himself; in short, to overturn our established faith, the common faith of the whole civilized world, to govern and direct man's social condition in a new method with his theory. But no, it cannot be. Gullible as some of the masses even of the nineteenth century have proved themselves, they cannot but see that these very doctrines which it is professed are to improve our social state, and to in crease our social happiness, actually outrage in their very outset the eternal principles of both!

Old English sense is yet too prevalent to permit her multitude to gorge the monstrosities of Owenism. In this confidence we should feel inclined to pass by the arch-deceiver with contempt, were there not a voice within our bosoms compelling to another course, "the voice of charity." We might stand by idle and unhurt, and watch the unholy flame of this new sect blaze for a little while, and pass again into darkness; but who can tamely bide the thought of all the poor fluttering and weak-minded rushing, moth-like, into the glare to perish: the easily deluded many-the

reckless or the ignorant? Ye pastors of Christ's people, watch and be vigilant, the greedy wolf that dare not attack the steadfast and the true, may devour the thoughtless and unwary of your several flocks.

For ourselves, we have no fear of the ultimate prevalence of Socialism. Whatever importance or dangerous influence it may appear to have obtained, seems to arise, like that of some diseases, more from the unhealthy state of the body affected than from its own intrinsic energy. Socialism may, for a while, serve to settle and stagnate the scum and garbage of England's thickly-populated, and at present excited country, till a return of sanity and vigour shall cast off this excrescence of its weakness. But we must not in the mean time forget that by its accursed doctrines, many a heart may be made sorrowful, and many a soul immortal perish, utterly and for ever, if deluded by these pernicious fallacies, from the cheerful hopes and godly promises held out to it in the faith of a Christian. W. M.

WATER.

It is the poet of nature who should write the history of water. Familiar, even to neglect, this is a wonderful substance, and we forget to admire; beautiful, and we do not note its beauty. Transparent, and colourless, it is the emblem of purity: in its mobility it is imbued with the spirit of life: a self-acting agent, a very will, in the unceasing river, the dancing brook, the furious torrent, and the restless ocean: speaking with its own voice, in the tinkling of the dropping cavern, the murmuring of the rill, the rush of the cascade, and the war of the sea-wave; and, even in the placid lake, throwing its own spirit of vitality over the immoveable objects around. And if its motion is the life of the landscape, it is, at rest, the point of contrast and repose for the turbulent multiplicity of the surrounding objects: a tempering shadow in reflecting the bright picture, and, as the mirror of the sky, a light amid darkness; while it is the colour to enhance what it contrasts, whether in its splendour or its shade.

Its singular oppositions of character are not less striking. Yielding to every impulse, unresisting, even to light, it becomes the irresistible force before which the ocean-promontory crumbles to dust, and the rocky mountain is levelled with the plain below; a mechanical power whose energy is without bounds. Of an apparently absolute neutrality, without taste, without smell, a powerless nothingness, that deceptive innocence is the solvent of everything, reducing the thousand solids of the earth to its own form. Again, existing at one instant, in the next it is gone, as if it were annihilated: to him who knows not its nature, it has ceased to be. It is a lake, and in a short time it is nothing: again it is that lake, and it is a solid rock. It is rock-crystal at one instant, and in the next it is invisible; while the agent of its invisibility transports it beyond the earth: that rock is air. Thus sailing in the heavens, it descends again, unchanged, again to renew the same ceaseless round: for ever roaming between the earth and the vacant regions of space; wandering about the earth below, in the performance of its endless duties, and though appearing at rest, resting nowhere. This, and more, is water: powerful in its weakness, and powerful in its strength : an union of feebleness and force, of incessant activity and apparent tranquillity, of nullity and ubiquity, of insignificance and power, a miracle of creation.-MACCULLOCH.

THE RAINBOW.

HAIL! beauteous meteor of the thousand dyes,
Emblazoned, like a trophy, on the skies.
Heaven's richest hues inlay thy lightsome span,
Kindled to glory; for a Sign to man.

Those vivid tints that through the welkin shine,
Proclaim thy matchless Architect divine.
Gemmed by the rain-drops, was the tissue spun
With golden threads irradiate of the sun,

Like stars enwreathed; whose myriad spangles throw
The prism's gay lustre to the world below.
Weft of mute music thou, whose pictured tones
Blend in accord, and melt in kindred zones.

Sweet solace ours, when lurid tempests frown,
To mark thy gradual braid th' horizon crown!
First, faint brief segments spring on either hand,
Whence lost abrupt, soon longer curves expand;
More massive, high upreared, the glowing form
In bolder contrast now bestrides the storm:
Fain its bright column would our arms embrace,
Yet at each step a fleeting beam we chase;
And whilst we fear lest ere the whole be viewed,
The subtle vision may our sight elude,
Mercy, fleet herald from the realms above,
Buoyed in the ambient air of heavenly love,
With stedfast key-link binds the quivering arch,
Then speeds thereon to Earth her volant march.

See! through the dark depths of th' unfathomed main
The mirrored brilliance softly gleams again ;
Warning the surges that their ruthless might
No more shall revel on the mountain height,
Nor through the fertile fields and valleys rave,
Engulfing Nature in the whirling wave:
No! for when 'neath Armenia's summits hoar
The shrunken waters lashed their slimy shore,
And found whene'er they strove beyond to roam,
The rising cliffs rebuke their baffled foam ;~
When the glad fathers of man s rescued race,
Exulting on the lone Ark's resting-place,
Had bent the knee, invoked the Almighty name,
Drawn votive blood, and fanned the sacred flame;-
When o'er fair Nature burst that sunny smile,
More lovely for her glistening tears the while;-
Then from the heavens was heard an awful voice
That bade the favoured patriarch rejoice:
Well pleased the Deity had seen arise
Prayer mingling with the smoke of sacrifice!
And now the solemn Covenant He swore,
That He would flood the new-born land no more;
Then rays from Heaven with tears from Earth He blent,
And wrote His promise on the firmament*.

View it†, vain man, whose dull unheeding soul No cheering hopes, no startling fears control, Nor the pale splendour of the moon absorbs, Nor the deep rapture of the hymning orbs; Whose sordid thought ne er searched Creation's laws, For the vast goodness of th' Omniscient Cause, Ne'er felt ecstatic joy when laughing May Wreathes with young flowers the verdant brow of day, Nor owned with transport chastened, awed, refined, Might on the mountain, wonder in the wind: Behold! and though thou deignest nought to bless, Yet inly scan thy very nothingness.

Such thou hast shone, bright Rainbow! when the sky
Has clothed in clouds its blue serenity;
And such shalt shine; while grateful for the vow,
All nations of the Earth to Heaven shall bow,
Curbing the tempest on its thunder-path,
Chaining the boisterous billows in their wrath;
Majestic symbol of thy Maker's might!
Girdle of beauty! coronal of light!

God's own blest hand-mark, mystic, sure, sublime,
Graven in glory to the end of time!

Nor dost thou live for Earth and Time alone :
In Paradise, around th' eternal throne
Thine emerald lightnings play‡; thine every gem
Is treasured for the Conqueror's diadem§,
When, with a shout that will Earth's centre rend,
Christ with His saints and angels shall descend,
Careering kingly over sun and star,

The winds His coursers, and a cloud His car :

* Gen viii, & ix. † Ecclus. xliii. 11. ‡ Rev. iv. 3. & Ezek. i.28. § Rev. x. 1.

No watery deluge then Earth's funeral pall,
But sulphurous flames enwrap the reeling ball.
Thus thy triumphal banner floats unfurled
Above the wrecks of this self-ruined world;
From cloud, from throne, from crown, betokening mild
Jehovah to lost sinners reconciled!
REV. THOMAS AGAR HOLLAND.

ON PHOTOGENIC DRAWING. No. III.
THE DAGUERREOTYPE.

THE developement of the secret of M. Daguerre's method of photography was occasioned by an arrangement between M. Daguerre and the Chamber of Deputies, by which a pension of 6000 francs, (about two hundred and forty pounds English), was bestowed on him, and one of 4000 francs, (about one hundred and sixty pounds,) on M. Niepce, with a reversion of half the respective amounts to Madame Daguerre and Madame Niepce. The discovery was therefore thrown open to general use in August last, when it was stated at the weekly sitting of the Academy of Sciences at Paris, by M. Arago. The greatest curiosity prevailed, all the seats allotted to the public were quickly occupied, and a crowd of persons disappointed of gaining admission, remained waiting in the court of the Institute, eager to catch the news of the important process.

The designs of M. Daguerre are executed upon plates of copper, covered with silver foil, and it appears that the combination of the two metals tends to the perfection of the effect. The silver must be the purest that can be procured, and the thickness of the copper must be sufficient to maintain the smoothness of the plate, so that the images may not be distorted by the warping of the tablet. The thickness of the two metals united should not, however, exceed that a stout card. The process is divided into Five

operations.

The first consists in polishing and cleaning the plate, in order to prepare it for receiving the sensitive coating, upon which the light is to act.

The second is to apply this coating.

The third is the placing the prepared plate in the camera, so as to receive properly the action of the light.

The fourth is to bring out the image, which is not at first visible.

The fifth and last operation is to remove the sensitive coating on which the picture is first impressed, otherwise this coating would continue to be affected by light, and would quickly destroy the picture.

The materials for the first operation, or the preparation of the plate, are pumice stone, finely ground and dried, olive oil, fine cotton, a phial of nitric acid, diluted with sixteen parts of distilled water, and a wire frame for placing the plate upon, while heat is applied to it by the spirit lamp. The size of the plate is regulated by that of the camera obscura.

The operation is begun by polishing carefully the surface of the plate. The pumice stone is powdered all over the silver surface, by shaking the bag which contains it, without touching the plate. With some cotton, dipped in a little olive oil, the operator then rubs the plate gently, beginning with the centre and rounding his strokes to produce equality of surface.

The plate is laid on several folds of paper, during this operation, and these are renewed at intervals, lest the tablet become bent or warped, through any inequality of support. The pumice stone must be renewed and the cotton changed several times. When the plate is well polished, it must next be cleaned by powdering it all over once more with pumice, and

rubbing with dry cotton, rounding and crossing the strokes as before. A little cotton is now rolled up, and applied to the mouth of the phial containing the diluted acid. The phial is inverted, and the centre only of the cotton is wetted, and that but slightly. The surface of the plate is now rubbed equally all over with the acid, but only in sufficient quantity just to skim the surface. If, as frequently happens, the acid run into small drops from the high polish, change the cotton, and rub down the globules as quickly as possible, but always gently rubbing, for if allowed to rest, or to run upon the plate, they will leave stains. It will be seen when the acid has been sufficiently diffused, by the formation of a thin veil spread regularly over the whole surface of the plate. It must then receive one more powdering of pumice, and be cleaned with fresh cotton as before. The plate must now be subjected to strong heat, and for this purpose it is placed upon a wire frame, made to support it over a spirit lamp, the silvered surface being uppermost. The spirit-lamp is now held beneath, and moved round and round, the flame touching and playing upon the copper. This must be continued for at least five minutes, when, if the lamp has been properly applied, a white strong coating will appear on the surface of the copper. A charcoal fire is perhaps preferable to the lamp, for the operation can be then more quickly performed, and the heat will be perfectly equal. If this method be adopted the plate must be held over the fire by pincers, until the veil appears. The plate is now to be cooled suddenly, by placing it on a cold substance, such as a marble table, a mass of metal or stone. When perfectly cold, the gummy appearance must be removed from the surface, by rubbing again with dry pumice and cotton, changing the cotton frequently. The polishing being thus completed, the operation of the acid is to be repeated three different times, dry pumice being powdered over the plate each time, and polished off very gently with the cotton, which must be very clean; care being taken not to breathe upon the plate or to touch it with the fingers, or even with the cotton upon which the fingers have rested, for the slightest stain upon the surface of the plate will prove a blemish in the drawing. If the plate is not to be used immediately, the last operation is not performed, for it is necessary that the final application by acid be performed on every plate immediately before placing it in the camera.

The second operation consists in coating the plate, and requires a small quantity of broken iodine and a small square box. In the upper part of this box the plate is fixed, with the face downwards, the copper surface having been previously fixed upon a board, by means of metallic bands and catches. A quantity of the iodine is placed in a saucer at the bottom of the box, and is covered by a piece of gauze, that the evaporation of the iodine may be regulated, and that the compression of the air on the lid of the box being closed, may not drive out any particles of iodine from the saucer, to the detriment of the silvered surface of the plate.

The apparatus is to remain in this position till the vaporization of the iodine has condensed upon the surface of the plate, sufficiently to cover it with a fine coating of a yellow gold colour. The time required for this effect to be produced varies from five minutes to half an hour. The plate must be taken out the instant a gold tinge is produced, or it will change to violet, and in this state be less sensitive to the impressions of light. These operations must be performed in a darkened apartment, by the feeble light of a taper, or the plate will be acted on too soon during

ment.

the moments in which it is necessary to raise it to examine how the work is going on. The evaporation of the iodine should be spontaneous, and it is important that the temperature of the interior of the box should correspond with that of the rest of the apartOn this account an apparatus in constant use, and impregnated with the vapours of iodine, will produce a much more speedy effect than a new box. The second operation is now over, and the third should immediately succeed it, for after the interval of an hour the action of the iodine and silver is no longer effective.

If

The third operation is the proper adjustment of the plate in the camera to receive the required images. This must be done quickly, avoiding light and contact, the camera having been previously fixed in the proper position. It is a task of some nicety to determine the exact time necessary to effect the desired object, and the operator must make the best guess he can upon the subject, for there is nothing in the appearance of the plate to guide him, the surface presenting no visible change when it is taken out of the camera. the sun-light be intense, three minutes will be sufficient, in other cases it may require thirty. The seasons, as well as the hour of the day, have considerable influence on the operation. The most favourable time is from seven to three o'clock, and a drawing taken at Paris in the months of June and July may be obtained in three or four minutes. In May or August it will take five or six minutes; in April and September seven or eight, and so on. Yet this is only the case when the objects are strongly illuminated, and it often happens that twenty minutes are required for the process in the most favourable months. All this will be ascertained by repeated trials, and the operator will learn to regulate the time during which the plate is to be exposed to the solar rays, so that the sketch shall neither appear vague and indistinct, nor black and heavy.

The fourth operation is the mercurial or disengaging process, by means of which the images are developed. A deep square-sided box, of the breadth of the tablet, is furnished with a cup containing three ounces of mercury. In this mercury the bulb of a thermometer is placed, and the top of the instrument is passed through a hole in one of the sides of the box. The box must have an opening below, so that a spirit lamp can be applied to the under part of the cup containing the mercury. The upper part of the box receives the plate, immediately on its being removed from the camera, the face of the plate being downwards, and inclined at an angle of 45°. Thus all is ready for the operation, and the fumes of the mercury are now disengaged by the heat of the spirit lamp, until the thermometer indicates a temperature of 140° Fahr., when it must be immediately withdrawn. If the thermometer has risen rapidly, it will continue to rise after the lamp is removed, but this ought not to exceed 167°. In a few minutes the faint tracery of objects will begin to appear, and this process must be examined by means of a small window in the side of the box, and by the light of a taper, but the taper must be used cautiously, that its rays fall not upon the plate. When the thermometer has fallen to 113o, or even before that, if the sketch appears complete, the plate may be removed, detached from the frame of wood in which it had previously been fixed, and if necessary it may be laid aside without injury, until it is convenient to perform the fifth process. Great care must, however, be taken to avoid its exposure to the light.

The fifth operation consists in fixing the impression by removing from the tablet the coating of iodine, on

A

which the light would otherwise continue to act. saturated solution of common salt, filtered through paper, and warmed, or a weak solution of hyposulphate of soda, which does not require warming, is poured into a square shallow copper trough, to the height of an inch. Distilled water is poured into a similar trough, and the plate is first plunged into the water and immediately removed, then immersed in the saline solution, where it is allowed to remain face upwards, till the yellow tinge has entirely disappeared. It is moved about by means of a little copper-wire hook, and as soon as the desired effect is obtained, it is removed from the solution with both hands (without touching the drawing) and plunged again in the pure water. It is then placed on an inclined plane, and distilled water, hot, but not boiling, is poured over it. The plate must then be dried rapidly by blowing on it, and moving it backwards and forwards in the air.

The drawing is now finished: it remains only to preserve it from dust and from vapours, which might tarnish the silver. It should therefore be placed in a square strong pasteboard with a glass over it, and be framed in wood. Without such preservatives, though the sketch will resist gentle washing, yet, as it will not bear the slightest rubbing, it will speedily receive injury.

Such is the process of M. Daguerre, and so mysterious is it, even now that the method of performing it is publicly made known, that M. Arago declares the sciences of Optics and Chemistry, in their present state, to be inadequate to give any plausible explanation of it. We may therefore well unite in the wish expressed by Mr. Talbot, at the meeting of the British Association in August last, that this discovery may be considered as "a call made on all the cultivators of science to use their united efforts, by the accumulation of new facts and arguments, to penetrate into the real nature of these mysterious phenomena." must also express our hope that as the subject becomes better understood, the process will be simplified, and placed within the power of those who are now totally debarred from entering on a work, which makes such extensive demands on their time and patience as the system of M. Daguerre.

INSCRIPTION ON A TOMBSTONE. ART thou a man of honest mould,

With fervent heart and soul sincere, A husband, father, friend? Behold! Thy brother slumbers here.

The sun, that wakes the violet's bloom,

Once cheered his eye, now dark in death; The wind that wanders o'er his tomb, Was once his vital breath.

But mark! the wind shall pass away,

The sun shall vanish from the sky; Thy brother's bones, in that great day, Shall live, and never die.

SAW ye the Sun, obscured at noon,

Burst through the mist, and fiercer blaze? Saw ye at eve the clouded moon

Shine out, and shed soul-soothing rays? Oh! thus shall truth's eternal beam Consume foul falsehood's venomed shroud : Thus, thus shall lovely virtue gleam Through calumny's malignant cloud!

LONDON:

We

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

WE proceed to notice the most important towns of the Regency of Algiers. MEDEYA. This place is situated a few miles southward of Algiers. On the road conducting towards it is the Café de Byrmadrais, as above represented. After leaving the city and proceeding for about half an hour towards the south, through a paved road bordered with thick hedges, the traveller enters a pretty valley, the sides of which are covered with picturesque rocks. Through the bottom of this valley flows a little brook, and at the point where the brook and the road meet are constructed a pretty looking coffee house, and a school, one on one side of the brook and one on the other. These were built after the defeat of the Spanish troops under Orelly, "to thank God for having aided the faithful to vanquish their enemies."

Proceeding onwards through a pleasant country, the traveller arrives at Medeya. (See p. 84.) On the left he sees many country houses, surrounded by fields and hedges.

struction. The aqueduct terminates in the town at a reservoir protected by powerful masonry, apparently to prevent any attempts to cut off the supply of water to the city.

There are two gates by which to enter Medeya, large but low, and on passing through that one leading from Algiers we enter a tolerably large street, with foot paths on each side, and a canal running through the middle. This street runs the whole length of the city, and has smaller streets branching out from it. Medeya is built on a hill, which is steep towards the west, and gently sloping towards the east. There are a few mosques in Medeya; in the one represented in the annexed cut, the door at the left leads into a small public school.

Medeya was the residence of the Bey of Titerie. He had in the town a barrack for janissaries, some handsome houses occupied by the principal Turkish officers, a large square building containing the magazine, and a palace. The exterior of this palace, represented below, nas no thing very elegant about it; but on entering through a door or porch, and passing through a corridor, a more elegant scene presents itself. A large square court is seen, paved with white marble and surrounded by a gal lery with arcades of Moorish achitecture, into which the

MOSQUE AT MEDEYA WITH TOMB-STONES AROUND.

Before entering into the town he passes under a lofty aqueduct, which brings water into the town from some neighbouring mountain; this aqueduct is composed of two lines of arches; and is constructed very substantially of chalk, clay, stone, and brick. Among the stones employed are many which seem once to have formed part of some Roman conVOL. XVI.