Εικόνες σελίδας
PDF
Ηλεκτρ. έκδοση

LESSONS IN ARCHITECTURE.- No. XI.

PRIVATE HOUSES.

Fig. 36

Homer, in his “Odyssey," informs us that the houses, and not appear that this construction always answered the purpose ; even the palaces of ancient Greece, were constructed of wood; and in Seneca, mention is made of the annoyance to which the and among others, he particularly describes that of Ulysses, at neighbours were subject from the disorderly conduct of those Ithaca. It is stated that the private houses of the early Ro. | persons who changed night into day by indulging in the false mans' wore small, and that the doors were left unclosel during refinement and late hours of the age in which he lived. In the principal mcal. As wealth and luxury increas« d, the size the Roman houses, also, there appears to have been, after the of their houses became so great, as to accommodate, in no very | Eastern fashion, a remote or inner court for the apartments of

the females, accessible only by an outer court for those of the Fig. 3i.

males, and of the servants. The information conveyed to us in the works of Vitruvius has received singular illustration and confirmation within a period less than a century, from the excavations at Pompeii, Herculaneum, and Stabia, cities which were overwhelmed by a tremendous eruption of Vesuvius, in

.4. D. 79, and which contained houses built and inhabited by NNK

Romans belonging to the age of Vitruvius. These excavations exhibit curiously paved streets, having the tracks of carriagewheels marked on them; and houses built of brick and rubble

work put together with mortar, all the materials being of very TUMKM inferior quality, except the interior coating of plaster, to which

Fig. 39.

[graphic]
[graphic]
[graphic]

11013e at Pompeii.

Ilouse built of Wood.

[ocr errors]
[ocr errors]

extraordinary cases, no less than four hundred slaves under a single roof. The height of private houses at Rome was re. stricted by the Emperor Augustus to seventy feet; but the irregularity of the city became so great, that, in one sense, its conflagration by Nero turned out a public good. For, being passionately fond of building, this made way for his architectural plans, and rendered Rome afterwards a regular and splendid city. Notwithstanding

l'ig. 38. these improrements, there was a great want of conveniences in the private architecture of the Romans. There was a general absence of chimneys and of windows; and

House of Francis 1, the only light received in the rooms was through an aperture

they appear to have been chiefly indebted for their durability. formed in or over the door. In

This plaster was composed of lime and pounded marble, a subthese respects, therefore, they were

stitute for stucco, and by its use a perfectly smooth and little removed from the rude cot

polished surface was obtained, nearly as hard as marble. With tages of the poor, still to be seen

this kind of stucco, the smallest apartments at Pompeii are in the remote parts of our own

found to be lined; and this lining is painted with various and country. One reason for the ne.

brilliant colours, and embellished with subjects either in the glect of comfort in their private

centre, or at equal distances, like panels. Painted imi. dwellings was, that they were not

tations of variegated marbles, forming, perhaps, a species of a domesticated people ; they lived

scagliola, also decorate the walls of their houses.

Few in public, and for the public; and Ilou:e of the Renaissance period. blocks of real marble are found, except in monuments their_society was to be found in

and public buildings; though, in imitation of the wealthy the Forum and public porticoes. A military people are sure Romans, the Pompeians inserted pieces or slabs of this to be thus circumstanced ; and France, at least in Paris, since material in their walls, and employed art to give them higher the first revolution, has presented a similar spectacle to the tints than those they possessed by nature. They also disobserver. Her inhabitants live in cafés, and in clubs or covered a method of veining slabs with gold; and leaves of this societies, but not at home.

metal covering the beams, walls, and even roofs of the houses, The arrangement of ancient houses greatly differed from the were introduced in great profusion. They covered their floors modern, in the formation of their internal courts. These were with cement, in which small pieces of marble or coloured usually constructed so that each was surrounded by apart- stones were regularly imbedded in geometrical forms; and in ments which, when lighted from within, prevented the domestic their best rooms they used mosaic (inlaid work) with ornaconcerns of the family from being overlooked by any one not mented margins and a device in the centre. The doors of included within the walls. From a passage in Plautus, it does their houses, being formed of wood, have been reduced to YOL. U.

35

[graphic]

THE POPULAR EDUCATOR

An

charcoal by the burning lava, and of course are found in an that which looks torrards the sea they are double the number of incomplete state; they turned on pivots, and were fastened by those next the garden. Before this portico lies a terrace, perfumed bolts which hung upon chains. Bedsteads are found, made with violets. On the upper end of the terrace and portico stands both of wood and iron; but their beds were made generally of a detached building in the garden, which I call my favourite ; and, carpets and vests, spread upon the ground. The articles of indeed, it is particularly so, having been erected by myself. 1: household furniture and convenience found in these remark- contains a very warm winter room, one side of which looks upon able ruins, are utensils of every kind in silver, brass, stone, the terrace, the other has a view of the sea, and both lie exposed

Through the folding-doors you see the opposite and earthenware, with vases of every size and adapted to chamber, and from the window is a prospect of the enclosed portico. every use; trumpets, bells, gridirons, colanders, saucepans, On that side next the sea, and opposite the middle wall, stands a some lined with silver, kettles, ladles, moulds for jelly or litile elegant recess, which, by means of glass doors and a curtain, is pastry, urns for keeping water hot on the principle of the either laid open to the adjoining room, or separated from it. Admodern tea-urn, horn-lanterns, spits, and, in fact, every joining to this is a bed-chamber, which neither the voice of the article of kitchen or other furniture used by us, except forks; servants, nor the murmuring of the sea, nor even the roaring of a chains, bolts, scourges, dice (some said to be loaded); a tempest can reach. This profound tranquillity is occasioned by a complete toilet, with combs, thimbles, rings, paint, pins, ear- passage which separates the wall of the chamber from the garden; rings, pearls, &c. But for more enlarged details, we must and thus by that intervening space every noise is excluded. refer to the work of Sir William Gell and J. P. Gandy, entitled nexed to this is a small stove-room, which, by opening a little win.

dow, warms the bed-chamber to the degree of heat required “Pompeiana.” In fig. 36 there is given representation of

Beyond this lie a chamber and antichamber, which enjoy the sun, one of the excavated houses of Pompeii. The excavated towns above mentioned being small, furnished though obliquely

, from the time it rises till the afternoon." specimins chiefly of houses inhabited by Romans of the The houses of princes, and the palaces of emperors, oecupied middle and lower classes. At Rome itself, the excavations of a great extent; and besides baths, gymnasiums, and gardens, the villa Negroni have made us acquainted with the nature of they had sometimes attached to them a basilica, a theatre, purely Roman houses, and of the higher class. To this may or a circus. Before the establishment of the Roman dominion be added the following description, by himself, of the winter in Gaul, the inhabitants, according to Vitruvius, lived in huts residence of Pliny the younger, &t Laurentinum, situated at of a cylindrical form, covered with shingle or thatch ; and, in the distance of seventeen miles from Rome, which gives us a Normandy, many vestiges of these are still to be found. The more distinct conception of the villa of a wealthy nobleman Romans gave to those people whom they conquered their of that city :

religion, laws, and customs; and the Gauls then built their

houses like those of Rome. Numerous villas, or country"My villa is large enough to afford all desirable accommodation without being extensive. The porch before it is plain, but not houses, and rural engineering residences, were to be seen in Gaul; mean, through which you enter a portico in the form of the letter many of these houses, as well as those built in towns, were D, which includes a small but agreeable area.

This affords a very constructed of wood placed on foundations of stone. Erected commodious retreat in bad weather, not only as it is enclosed with in a climate different from that of Italy, the Gallo-Roman windows, but particularly as it is sheltered by an extraordinary pro- liouses, especially in the northern parts, were warmed by subjection of rool. From the middle of this portico you pass into an terranean flues, called hypocausts. During the first ages of inward court, extremely pleasant, and thence into a handsome hall, the monarchy, houses in Gaul or France were made of wood, which runs out towards the sea. On every side of this hall there exactly similar to those of the Roman period. In a description are either folding

doors, or windows cqually large, by which means of the palace of Attila, given by the Byzantine historians, you have a view from the front and the two sides, as it were, of some valuable information is to be found on this subject. Some three different seas ; from the back you see the middle of the houses in stone, erected during the Roman period, are still to court, the portico, and area ; and by another view you look through be found in France, with façades very similar to those of the portico in to the porch, whence the prospect is terminated by the woods and mountains which

are seen at a distance. On the left- modern erection. In the towns of the south, and of the centre hand side of this hall, somewhat farther from the sea, lies a large of France, such as Nismes, Perigueux, Metz, and Cluny, there drawing room, and beyond that a second of a smaller size, which remain some ancient specimens of this kind of architecture ; has one window to the rising and another to the setting sun. The and there are some also in Germany and Italy. In the 13th angle which the projection forms with this drawing room retains century the Gothic style was used as much in private as in and incrcases the warmth of the sun; and hither my fanıily retreat monumental or public architecture. In the town of St. Yrieix, in winter to perform their exercises. Contiguous to this is a room there is a very fine house built in this style; and others are forming the segment of a circle, the windows of which are so found at Montpazier, in the department of the Dordogne. placed as to receive the sun the whole day; in the walls are con Rural constructions, farms, and granges, are found at Meslay fained a set of cases, which hold a collection of such authors whose in Touraine, and near Coulommiers. Both in the 14th and chamber through a passage, which, being boarded, and suspended 15th centuries, wooden houses were common all over Europe. over a stove which runs underneath, tempers the heat, which it Fig. 37 is a representation of one of these, of which many receives and conreys to all parts of this room. The remainder of specimens may be seen in England. The stories of these this side of the house is appropriated to the use of my slaves and houses were executed in corbel, that is, projecting one over freedmen; but most of the apartments are ncat enough to receive the other,--an arrangement by which the upper rooms were any of my friends. In the opposite wing is a room ornamented in enlarged, but which rendered the lower storie un wholesome, a very clegant taste; next to which lies another room, which, the light and the air being prevented from entering freely into though large for a parlour, makes but a moderate dining room. the rooms they contained. This system of projecting stories Beyond is a bed-chamber, together with its antichamber, the is proved to be of Oriental origin, from the circumstance that height of which renders it cool in summer, as its being sheltered it did not make its appearance in Europe until after the time on all sides from the winds makes it warm in winter. apartment another of the same sort is joined by a common wall. of the Crusades. This system, which was proper in the East, From thence you enter into the grand and spacious cooling room for defending the lower part of the house from the light and belonging to the bath, from the opposite walls of which two round heat of the sun, was absurd in climates where these basius project, sufficiently large to swim in. Contiguous to this is always welcomed as delightful visitors. After the 13th centhe perfuming room, then the sweating room, and next to that the tury, houses were constructed so that the gable-end of the roof furnace which conveys the heat to the baths. Adjoining are the fronted the street; and in the middle ages, "to have the gable two little bathing rooms, fitted up in an elegant rather than a costly to the street" indicated the right of citizenship. Built with

At the other end is a second turret, in which is a room out a regular plan, these houses were, owing to the arrangethat receives the rising and setting sun. Behind this is a large re. pository, near to which is a gallery of curiosities, and underneath stairs were constructed outside, and in front of the building;

ment of the windows, both dark and inconvenient within ; the is a spacious dining-room. It looks upon the garden and the ride and in the recesses thus formed, turrets were built, which in which surrounds the garden. Between the garden and this ride is the 15th century were greatly multiplied, and added to their a banquetting room. the windows of which look upon the entrance to the villa, and into decoration. Wooden façades were generally more decorated a pleasant kitchen-garden. From hence an enclosed portico ex. than those constructed of stone; the posts, the beams, and tends, which, by its great length, you might suppose erected for the the panels, were covered with a profusion of sculpture in wood; use of the public. It has a range of windows on each side, but on the roofs were decorated with elegant crests and graceful

were

manner.

spires, surmounted with whimsical weather-vanes. During the Renaissance the outward appearance of houses, as well as their internal accommodations, were greatly improved; the façades became more regular, and wood more rare; and when used, it was mixed with brick and stone. From this period, sculptures were spread over the fronts of houses with less profusion, and with more taste. There are many specimens of houses built in the Renaissance style, in France, Germany, and Italy, as well as in England. The ancient towns of Rouen and Moret, in France, furnish some of the finest examples; and in fig 38, there is a representation of a house of this kind at Rheims. Since that time to the present day, private architecture has extensively improved; the outward appearance of our houses has become less fantastical, and the interior arrangements more convenient. Within the present century the improvements in private edifices have partaken of the progress of the arts, and are as great in their decoration as in their adaptation to the comfort of human life. To the illustrations of this article, we have added (in fig. 39) a representation of the house in Paris, occupied as a residence by Francis I., King of France, who ascended the throne

in 1515.

LESSONS IN LATIN.-No. XXXIII.
By JOHN R. BEARD, D.D.
DEVIATIONS IN THE THIRD CONJUGATION.
1. Perfect in si; Supine in sum.

a. The stem ends in d or t; e. g., claud, mit. i. Claudo, claudere, clausi, clausum, I shut. The compounds have clūdo, clusi, clūsum; as includo, I shut up. Divido, dividere, divisi, divisum, I divide. Laedo, laedere, laesi, laesum, I injure. The compounds have līdo; as, illīdo, illīdere, illise, illisum, I strike against. iv. Lūdo, ludere, lusi, lusum, I play.

ii.

iii.

V.

Plaudo, plaudere, plausi, plausum, I clap my hands. So applaudo, I signify approbation by clapping; the other compounds have ōdo, osi, osum; as explodo, I drive out by clapping

hands.

vi. Rado, radere, rasi, rasum, 1 graze, shave (E. R. razor). vii. Rodo, rodere, rosi, rosum, I gnaw, slander. 1 viii. Trūdo, trudere, trusi, trusum, I thrust. ix. Vado, vadere (no perfect, no supine), I go. Both perfect and supine are in the compounds; as, evado, evadere, evasi, evasum, I go out, get away.

X.

Cedo, cedere, cessi, cessum, I yield. xi. Mitto, mittere, misi, missum, I send. xii.

Quatio, quatere (no perfect), quassum, I shake. The compounds have cutio, cussi; as, decutio, decutere, decussi, decussum, I shake down.

b. The stem ends in g, c, or ct.. xiii. Mergo, mergere, mersi, mersum, I dip.

xiv. Spargo, spargere, sparsi, sparsum, I scatter, sow. Compounds, spergo, spergere, spersi, spersum; e. g., conspergo, I sprinkle.

XV. Tergo, tergere, tersi, tersum, I wipe. Another form of tergeo, tergere.

xvi. Figo, figere, fixi (ficsi), fixum, I fix, fasten.
xvii. Flecto, flectere, flexi, flexum, 1 bend.
xviii. Necto, nectere, nexui, nexum, I tie, knit.
xix. Pecto, pectere, pexi, pexum, I comb.

XX.

Plecto, plectere, plexi (rare), plexum, I weave. Here may be placed, also, these two :

xxi. Premo, premere, pressi, pressum, I press. Compounds, primo; as, comprimo, comprimere, compressi, compressum, I press together.

xxii. Fluo, (stem, fluvo; noun, fluvius, a river), fluere, fluxi (fluxus as an adjective), I flow.

VOCABULARY.

duration, durability; viritim, man for man, among the men; Numa, ae,
ni Numa, the Roman king of that name; Janus, i, m. Janus (Dianus),
a Roman divinity.
EXERCISES.LATIN-ENGLISH,

Templum Jani bis post Numae regnum clausum est; si ridére concessum sit, vituperatur tamen cachinatio; si concesseris esse Deum, confitendum tibi est, ejus consilio mundum administrari; in omnium animis Dei notionem impressit Deus ipse; magna vis est conscientiae, ut qui peccarint, poenam simper ante oculos versari putent; virtutes ita copulatae, connexaeque sunt, ut omnes modios ac totidem olei libras, trecenos quoque nummos viritim omnium participes sint; Caesar populo praetcr frumenti denos divisit; qui diffidit perpetuitati bonorum suorum, ei timendum est, ne aliquando, amissis illis, sit miser; Plato duas partes animi, iram et cupiditatem, locis disclusit; iram in pectore, cupiditatem subter praecordia locavit; omnis Gallia in tres partes divisa est; si quis imprudens (without intending it) te laeserit, non decct ei irasci; si vitae molli et effeminatae te dederis, brevi tempore omnes nervi virtutis elisi erunt; cur me elusistis? nescisne a perfido amico me delusum esse? histrionibus qui heri praeclare partes suas sustinuerunt, omnes spectatores applauserunt; Epicuri de vitâ beatâ multi qui in pecuniâ corrasâ vitae filicitatem collocatam esse putent. sententia ab omnibus acutioribus philosophis explosa est; sunt

ENGLISH-LATIN.

My house was shut yesterday; I will shut thy house; the temple is being shut; the temple will have been shut; the boy has been shut out of the school; they concede that there is a God; they must confess that there is a God; God has impressed an idea of himself on all minds; I will divide a hundred bushels of wheat (among them), man for man (100 bushels to each man); are not the virtues united together? he who distrusts in God, must fear that he may sometime be miserable; dost thou distrust in God? good men yield to the will of God; the mouse gnaws the meshes of the net; spectators will applaud good actors; the ships get away out of the enemy's hands; are you ignorant that Gaul is divided into three parts

VOCABULARY.

Concludere, to enclose; confluere, to flow together; diffluere, to flow abroad; defigere, to fasten (in aliquâ re); transfigere, to pierce, stub; deflectere, to bend down, turn on one side; demergere, to sink, to let down; emergere, to come up (out of the water), emerge; detrudere, to push down; extrudere, to push out; discutere, to scatter, frustrate; dispergere, to scatter abroad; dispicio, spexi, spectum, to open the eyes; exagitare, to torture; exanimare, to kill, pass., to lose one's life, die; exsibilare, to hiss off; fugare, to put to flight; ut primum, as soon as; hasta, ae, f. a spear; nebula, ae, f. a cloud; clypeus, i. m. a shield; stimulus, i. m. a goad; caligo, inis, f. darkness; salvus, safe, saved; mobilis, e, moveable; quondam, formerly; dissipo 1, I spread abroad; apud Mantinéam, at the battle of Mantineam.

EXERCISES.-LATIN-ENGLISH.

Te in tantum luctum et laborem detrusum esse graviter doleo; cur aedibus istum extrusisti? spero amicum aegrotum e morbo evasurum esse; si animus e corpore evasĕrit, tum demum vivet et vigebit; sole orto, caligo discussa est; omnia pericula, quae urbi impendebant, ducis fortitudo et consilium discussit; Marius senile corpus paludibus demersum occultavit; animus coelestis ex altissimo domicilio depressus, et in terram quasi demersus est; leges perlongum tempus hostium vi dimersae, tandem emerserunt; Deus immortalis sparsit animos in corpora humana; omnia quae nunc artibus conclusa sunt, quondam dispersa et dissipata fuerunt; Epaminondas apud Mantinéam gravi vulncre cecidit; Epaminondas Lacedaemonios superavit; Epaminondas salvus ne esset clypeus interrogavit; Epaminondas quum superasset Lacedaemonios apud Mantineam, atque ipse gravi vulnere exanimari vidéret, ut primum dispexit, interrogavit salvus ne csset clypeus; quum salvum esse a flentibus suis audisset, rogavit, essent ne fugáti hostes; quum id quoque audivisset, evelli jussit eam, quâ erat transfixus, hastam ; alia omnia incerta sunt, cadúca, mobilia; virtus est una altissimis defixa radicibus; Cicero omnes suas curas cogitationesque in reipublicae salute defixit; qui semel a veritate deflexit, ei ne verum quidem dicenti fides haberi solet; non credo te unquam de virtutis viâ deflexurum esse; dic cui hanc corónam nexueris; ingens heminum multitudo in urbem confluxit, ludos publicos spectatum.

ENGLISH-LATIN.

Where will Marius hide himself? Marius has hidden himself in Committere, to commit, do; concedere, to concede, grant; connectere, the marsh; will the soldiers hide their bodies in the marsh; the to connect, put together; corradere, to scrape together; deludere, to de- minds of men have been let down from heaven to the earth; the lude, 'deceive; eludere, to insult, scoff at; discludere, to shut apart, men who were sunk have come up; the soldier loses his life by that separate; elicere, to dash against; imprimere, to print, impress; copu-heavy wound; I saw two men die in battle, being pierced with lare, to bind in couples, to bind together; locare (in. and abl.), to place; spears; the dying soldier opened his eyes and asked if the enemy libra, ae, f. a pound; modius, i, m. a bushel; regnum, i, n. a reign; were scattered; all other things but God are perishing, God remains, praecordia, orum, n. the diaphragm; cachinnatio, onis, f. a loud and ever will remain, fixed in the deep (altus) roots of his own life; laugh; histrio, ónis, m. a player; perpetuitas, átis, f. perpetuity, the young man has turned aside from the way of virtue; dost thou

think that thy disciples will turn away from wisdom? bad men are sunk in miseries; my sister wove a crown for the poet; I will weave a crown for thee, my dearest mother; a multitude of men will flow into the city; they will come to see the queen and behold the public games; the clouds are scattered; the sun has shone forth; come, let us take a walk, and hear the birds sing their sweet songs; God has scattered the seeds of virtue in all minds.

PAVO. Aesopii Fabulae. 3 4 6 Pavo graviter conquerebatur apud Junonem, dominam suam, 8 10 9 12 3 4

1

2

5

7

11

1

2

quod vocis suavitas sibi negata esset;

dum luscinia, avis tam

5

6

8

7

2

5

3

7

parum decora, cantu excellat. Cui Juno, "et merito," inquit; "non

8

6 9 10 12 13 11 enim omnia bona in unum conferri oportuit."

[blocks in formation]

When a river rubs against a rock, and wears it away by attrition, as if by filing or planing it; when it undermines the rich soil at its brink, as if by excavating it; when it carries along suspended in it, mould, gravel, or wood; and when it leaves such materials behind it on its banks, or deposits them quietly when it comes to a state of comparative rest, as in some deep pool in its bed, or at the bottom of the sea; such effects are ascribed to the mechanical action of water. They are all effects which could be produced by the instrumentality of machinery.

VOCABULARY.

Conqueror 3, I complain; apud, before; Juno, ónis, Juno, a Roman female divinity, the queen of heaven; nego 1, I deny; luscinia, ae, f. a nightingale; et merito, and deservedly, properly so too; confero 3, I bestow; oportet (perfect, oportuit), it is right, becoming.

ANSERES ET GRUES.

In eodem quendain prato pascebantur anseres et grues. Advenienti domino prati, grues facile avolabant; sedanseres, impedíti corporis gravitate, deprehensi et mactati sunt.-Sic pauperes cum potentioribus in eodem erimine deprehensi, soli dant poenam, dum illi salvi evadunt. VOCABULARY.

Quondam, formerly; pratum, i, n. a meadow; pascor, pasci, pastus sum, I feed; impedio (pes, a foot) 4, I hinder; deprehendo 3, I catch; macto 1, I slaughter; pauper, eris, a poor man; potentior (comparative of potens), more powerful; crimen, criminis, n. an accusation, crime; dare poenam, literally, to give punishment; that is, to suffer punishment.

CONSTRUCTION OF DARE POENAM, &C.

Poena, from the Greek poine, originally denotes the sum of money by which impunity was purchased, or satisfaction was given to the injured. Hence it meant, in general, redemptionmoney, or the means of escape; a penalty, or the suffering undergone in consequence of a crime. But as the root idea is that of a fine, or mulct, so the guilty were said to give the payment or punishment (dare pocnam), and the injured to take payment or punishment (sumere poenam). The plural of the nouns is also used. Accordingly, we have two classes of expression, the instances of which come under:

To give punishment

i. e.. to be punished

dare poenam, or poenas to give the penalty Ssolvere poenas

to pay the penalties Spendere poenas to pay the penalties

To take punishment

i. e, to punish
sumere poenam, or poenas
to take the penalty

suscipere poenas.

to take the penalties

petere poenas

ecek, or require the penalties

VOCABULARY.

Repeto 3, I seek, require; reus. i, m. an accused person; Poeni, orum, m. the Carthaginians; temeritas, átis, f. rashness; calidus, a, um, hot; scelera'us, a, um, wicked.

EXERCISES.-LATIN-ENGLISH.

Repetit poenas filio pater justus; reum mulctavit mulctâ maximâ civem judex; avum annis debilem affecit consul gravi poenâ; poenam dignam suo scelere suscipere non potuit Cicero; vobis victi Poeni poenas sufferant; maximas poenas pendo temeritatis meae; pro vestris maledictis poenae pendentur mihi hodie; calido dabis sanguine poenas; poenas gravissimas ex sceleratis hominibus sumserunt judices.

ENGLISH-LATIN.

I will inflict punishment on bad boys; bad boys will be punished; bad boys will have to suffer punishment suitable to their evil deeds; the judge punished the criminals very severely; being conquered you will suffer punishment from (Lat. to) the conquerors; I have been punished; I will punish them.

You have now learnt that the chemical action of water is

One or two other forms which appear in these exercises will two-fold. It has the power of corroding and dissolving rocks now be readily understood.

and materials on which it acts; and it has the power of depositing the ingredients which it has held in solution.

The solvent or dissolving action of water is greatly assisted by the presence of carbonic acid, ammonia, and other elementary substances which combine with it. Even the rain, before it falls on the earth, collects a considerable quantity of carbonic acid from the atmosphere. When such a fluid penetrates into the earth's crust and percolates amid calcareous, siliceous, and ferruginous rocks, that is, amid strata containing lime, flint, or iron, the action of carbonic acid upon such rocks will be very great. When such impregnated water issues again, from deep sources, as a spring on the surface, and at a high temperature, it acts much more readily and extensively than when pure and cold.

Carbonic acid gas is that which you sometimes find bubbling

You have seen that when a drop of water is left upon polished steel, or when any iron is exposed to moisture and rain, the water produces on the surface of the iron and steel a rust, which is called by chemists the oxide of iron. This is produced by the chemical action of water. If water also be left on the surface of a limestone, it produces, before it evaporates, a small indentation, which by the repeated settling of water upon it, becomes a well-rounded hole. These circular little basins, the result of water eating into the stone, are found everywhere in limestone rocks which are occasionally overflowed by streams and torrents. Some such indentations are found in the surface of rocks near the sea-side, and within reach of the tides. They retain some portion of the salt water after the tide has retreated. In cases where this salt water has had time to evaporate before the tide reaches that indentation a second time, you have found that the exhaled water has left behind it a deposit of salt. All these and similar actions of water in corroding the iron, in dissolving the limestone, and in depositing the salt, are chemical. They are effects produced, not by any force or motion of the water, but by the gaseous and other elements which it contains in solution. If, in washing, you leave your soap in the water, the water will act chemically upon it, and dissolve it. If you empty the basin with the soap in the water, the water will mechanically carry it away, and deposit it at some other spot.

It is necessary also that you should well understand the difference between water holding any matter in suspension, and its holding it in solution. When a clear stream becomes muddy, it holds particles of clay or sand in suspension. When your tea has been sweetened, it holds sugar in solution. All water contains some gaseous and earthy elements in solution. Even the purest springs are impregnated with some foreign ingredients, which, being in a state of chemical solution, are so intimately blended with the water as not at all to affect its clearness. Such mingled ingredients, though invisible, render the water, in general, more agrecable to the taste, and more useful for nutrition than simple rain water. When springs contain earthy elements in great abundance, they are called mineral waters; and many of them are thermal or hot wells, which have been described to you in a previous Lesson.

WEST

B

FAST)

up like small globules in stagnant pools. This is the gas which to the east and west. The fundamental rock is black slate accumulates at the mouth of limekilns, and which has been with serpentine. Near the summit a spring issues. The water the cause of so many sudden and immediate deaths. This is hot, has a strong taste, and is generally of a bright green gas has the property of decomposing many of the hardest colour. This well deposits its calcareous ingredients very rocks, especially where felspar is an ingredient, as in granite rapidly. At the bottom of a large conduit pipe for conveying and gneiss. Its effects are manifest on all rocks, but particu- the water from the spring to the bath, a pipe, remember, that larly on limestone. It is only in limestone rocks that the has the inclination of 30 degrees, a deposit of travertin, six carbonic acid can dissolve all the constituent parts of the mass. inches deep, is formed every year. Where the water flows at This is the reason why calcareous rocks are almost the only a less angle and more slowly, the travertin is more compact. ones in which great and lofty caverns, with large winding And, in winter, when the evaporation is least, the sediment is passages, are found.

said to be more solid, but about one-fourth less in quantity The corrosion and destruction of many of the elements of than it is in summer. This rock is mostly white, and some of rocks by the dissolving power of carbonic acid, whether in a it so hard and compact that it rings to the hammer. gaseous state, or combined with spring water, in the crevices A careful study of the formation of limestone beds at San and crannies of rocks, is one of the most powerful causes of Vignone will throw much light upon the inquiries of the young those internal changes, and of those subsequent re-arrangements geologist. Here you find the underlying rock of black slate of particles, which geologists have detected in rocks and fossils coated on each side, east and west, with a white limestone. of all ages. As an instance I may remind you that you have The beds of travertin descend the hill from the point where the often seen in hand specimens an imbedded shell containing a calcareous spring rises. The beds take the slant of the hill, yellow shining substance almost like gold. That yellow shin. and the planes of the stratification are perfectly parallel to each ing matter was not originally in the shell. That part was first other, though they all rest unconformably on the ancient rock occupied by calcareous or limy matter, which was removed by of black slate. Among these beds there is one remarkable the carbonic acid, and then was replaced by the carbonate of stratum which consists of many small layers or laminated sediiron, of copper, or some other chemical ingredient such as ments. This stratum is fifteen feet thick, and its structure is mineral water holds in solution.

so compact as to form a good building stone. Another portion As water containing carbonic acid has percolated among of these beds descends the side of the slate rock towards the beds of lime, flint, iron, &c., so the springs produced by the west, This is of varying thickness, but in some places it is re-appearance of such water are called calcareous, siliceous, two hundred feet deep. Its course terminates abruptly, for ferruginous, &c., according to the earthy or mineral character its progress has been cut off by the current of the river Orcia. of the rocks which have further impregnated the water. As the termination of the travertin is here very abrupt and i. Calcareous Springs.

almost overhanging, it is evident that the beds would have

continued further had it not been for the action of the Orcia. Many springs contain limy or calcareous matter in great | This is proved by the facts that the river is constantly underabundance, and the phenomena of their influence upon rocks mining the travertin, and that solid fragments of it are found are of great interest in geology. It is found that even rain- scattered amid the alluvium of the stream. water has the power of dissolving limestone. This is a wise arrangement designed by the God of nature. It is by this

Fig. 43, action that even in the smallest pool or streamlet matter is furnished for the earthy secretions of the little shelly animals that live in such water, and also for the growth of certain plants on which they feed.

When springs have gained accession of carbonic acid, by their waters having percolated among limestones, they can dissolve a much larger quantity of calcareous matter than rainwater. When this acid becomes again dissipated in the atmosphere, such water deposits its mineral ingredients in the channel of its current. The matter which it deposits is called tufa and travertin. When the deposit is loose and cellular it is called tufa; when the deposit is compact and hard it is called travertin. The substance of the sediment is, in both cases, precisely the same.

Though calcareous springs abound most in limestone districts, they are by no means confined to them, but flow in rocks of all 'formations and ages. In Auvergne, in central France, springs copiously charged with carbonate vi lime rise up in rocks of granite and gneiss. One of these springs, near Clermont,

Section of Deposits of Trarerlin, at Sl. l'ignore', Tuscany. has formed, by its deposits and incrustations, an elevated mound of travertin ; that is, a white concretionary limestone. In fig. 43, which represents a section of the district about the This sedimentary bed of limestone, formed by the spring, is baths of San Vignone, sss designates the fundamental rock of 240 feet long, 16 feet high at its termination, and 12 feet wide. black slate. A, the point at which the spring began to issue and

In the valley of the Elsa, belonging to the Appenines, in to deposit its sediments. ace x :, the successive beds of traverItaly, there are innumerable springs which, in their flow, have tin which the spring has deposited on each side until it has precipitated or deposited so much calcareous matter that the reached 1, its present position at the baths. c marks the whole ground in some parts of Tuscany is coated over with beds to the east. D shows the abrupt and overhanging terminatufa and travertin. This ground sounds hollow beneath the tion of the beds to the west, where it is stopped by the underfoot. In the same district you can see compact rocks of traver- mining action of the river Orcia at e. tin or limestone descending along the slanting sides of the hill, You perceive that the mass of sedimentary strata precipitated much like the beds of cooled lava on the sides of Etna, except by this one spring must be enormous. After all, even this, is that these travertins are of white colour. These sloping beds insignificant compared with the quantity which has been terminate abruptly as they reach the course of a river at the carried to the sea, since this spring has commenced its activity. bottom of the hill. Geologists can prove that all these strata It cannot be ascertained, at what time the spring began to of travertin have been formed by calcareous deposits from the Aow: but it is remarkable, that in quarrying some of the beds, springs. Some of these springs are still flowing, others have Roman tiles have been digged up at the depth of five or six disappeared.

feet. One of the best illustrations of the action of these calcareous The limits of our Lesson will not allow us to notice the cal. springs is formed at the baths of San Vignone, in Tuscany. carcous springs of San Filippo, of Bulicami, and of Civita San Vignone is on a hill about a hundred feet high. The top Vecchia, and of other places. There is, however, one reof the hill is fla', and stretches in a gently inclined platform markable phenomenon connected with such springs which it

D

1:

[ocr errors]
« ΠροηγούμενηΣυνέχεια »