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LESSONS IN GEOLOGY.–VI.

of four groups. The Andes, which edge the western shore of

the American continent, present in their chain many active, and VOLCANOES-IGNEOUS AGENCY.

numerous extinct, burning mountains. This is the best defined The universal action of water is to level. If the world continue volcanic group. A second is recognised as comprising the for the requisite number of ages, and if no other cause interfere | Aleutian Islands, Japan, the Moluccas, and the volcanoes of the with the degrading and filling up which is carried on by

East Indies. The third group includes those of the every rain-drop, river, or ocean current, in due time our

Pacific Archipelago ; while the fourth is represented as world will be a level plain. This, however, can never

stretching from Central Asia to the Azores, and includes be the case, for there exists a force which constantly

the volcanoes of the Greek islands, and those of Southern opposes the action of water. The Creator " hath set the

Italy. one over against the other," and here, as in every domain

A remarkable fact will at once strike the observant of Nature, is a finely adjusted balance—the aqueous

reader, namely, that all volcanoes are in the immediate agency on the one hand, and the igneous agency on the

neighbourhood of the sea. other; the one wearing down, the other elevating; the

There is no exception to this rule. In Central Asia one filling up and making the surface even, the other dis

there is said to be a volcano on the north declivity of rapting and throwing the existing arrangement into dis

the Thian-Shan Mountains, but its last eruption is referred order.

to the seventh century. There are not wanting evidences The action of heat is exerted in three ways—(1) in

that in that part of Asia large bodies of water existed, volcanoes, (2) earthquakes, and (3) the gradual upheaving

and even now the large lake Issik-Kul is in the neigh. or subsiding of portions of the earth's crust. We are

bourhood of the quiescent mountain. This apparent nenot able to trace the action of heat so certainly as that

cessity of being in immediate proximity to water, caused of water, for the simple reason that we can watch the

Bischoff to propound a theory, which is generally acone from first to last; whereas we can only study the

cepted: that the immediate cause of volcanic action is effects of thermal action, and thence attempt to divine

due to the fact that water percolates through fissures in the causes.

the surface down to the hot regions beneath; here it is Wherever there is room for speculation, no lack of

made steam at a high pressure, and thus forces for itself speculators has been found; and upon almost every

a passage through the superincumbent crust, urging with question upon which a doubt could exist—and there are

it molten matter, and the débris caused in the upheaval many in this part of the subject—the geological world has

of the strata, to produce a vent. Whether water be a been divided. We shall notice the prominent points of

requisite to volcanic action or not, one thing is oortain, the various controversies as we discuss the subjects as

that no volcano can exist without heat. they present themselves.

Many geologists hold that the centre of the earth is 1. Volcanoes.-We shall find that rocks which owe

AI

still composed of molton matter, and that the lines traced their origin to igneous action may be safely divided

by the volcano-chains mark the direction of vast fissures into plutonic and volcanic rocks. In the former class

Fig. 10.

in the earth's crust up which, by the pressure of steam, the are arranged all rooks of the primary formations, such

lava is forced. A grave objection at once appears to the as granites, etc., which are the offspring of a much more general | acceptance of this assumption. If this be the case, according and widely extended action than those igneous rocks which date to the laws of hydrostatics, the pressure exerted at one point from a much later period. These rocks, which are found within by the expanding steam must be felt by the whole liquid mass, limited ranges, have been ejected from a crater, that is, a hole for liquids transmit pressures equally in all directions ; hence is formed from the surface to the bowels of the earth beneath, the same force which throws into action one volcano, must also op which is thrown molten

cause all the neighbouring lee and ashes, or scoriæ.

cones to erupt. This arguThis matter is cast up and

ment finds a remarkable exfalls around the opening,

ample in one of the Sandforming a hillock, the top of

wich Islands. Mauna Loa is which is a cup-like forma

a volcano frequently active; tien, at whose base is the

there is a crater near its summouth of the volcano. A

mit, 10,000 feet above the mountain thus entirely

level of the ocean; 6,000 feet formed of material ejected

upone flank is another crater, from the centre of action be

Kilauea. It often happens, Death, is called a crater of

that while Loa is in action, tription. However, another

the lava in Kilauea is molten, method of construction of a

yet undisturbed. It seems volcanic mountain can be

an inevitable conclusion, that imagined, where some violent

if these eraters both derive upheaving force lifts up the

their lava from the same resurface into a bubble-like

servoir, the force which pro mound; the apex, being natu

pels the molten matter to the cally the weakest part, gives

higher crater must cause a way, and from the opening

jet of lava to be thrown from thus formed the internal fires

Kilauea to a similar height. belch forth, and the eruption

That simultaneous disproceeds, the walls of the

turbances would take place babble falling down from the

in each crater, if their ducts mountain. A volcano thus

led to the same reservoir, produced is styled a crater of

may be fairly inferred from elevation. These two theories

the fact, that we have nuhave been energetically sup

merous accounts of volcanic

Fig. 11. ported by eminent geologists.

action occurring at the same Serope, Prevost, and Lyell are

moment at many distant adherents of the eruption theory, whilst Humboldt, Elié de Beau points: for example, a severe earthquake visited Chili in 1835; mont, Dufrénoy, and others, maintain the theory of elevation. at the same moment the shock was felt over a wide area; thé We shall find that there is some truth in each theory, but that two volcanoes, Vantales and Osorno, burst into action; and at no volcano owes its origin entirely to elevation or eruption, both Juan Fernandez, 720 miles distant, a submarino eruption took processes having taken part in the erection of the mountain. place.

Thus the commotion in some deep-seated reservoir It is supposed that all the volcanoes in the world are members affected a tract of country 900 miles long and 600 broad.

68

[graphic]

VOL. III.

It has long been a theory pertinaciously adhered to, that the when the chemical action was exhausted. Moreover, we most centre of the earth is now in a state of molten incandescence, remember that air in a condensed state acqnires a lower specific and that all volcanoes dorive their igneous action from the heated heat, that is, its capacity for containing heat is decreased; hence centre. In conjunction with the existence of burning moun. an increment of heat will have a much greater effect in increastains, another fact is adduced, which appears to give great ing the temperature at the bottom of a mine than on the surface. weight to the supposition. It is generally found that in In the case of well-waters, the chemical action is induced by the descending the crust of the earth the temperature increases. ' gases they hold in solution acting upon the rocks through which Numerous observations in mines and artesian wells have been they percolate, and on the sides of the subterranean reservoirs made, and it is concluded that in England the thermometer in which they collect. Sir Humphry Davy, Danbeny, and others, rises 1° Fahr. for every 55 feet descended.

| ascribe even volcanic heat to chemical action. The discoverer of The reader must not suppose that this increase is at all the metals of the alkalies, potassium and sodium, supposed that at uniform; indeed, Kupffer, from very extensive comparisons, the base of burning mountains were vast deposits of these metals; infers that the increase is 1° Fahr. for every 37 feet, while that when water found its way to the metal it became decomposen, Cordier gives the same angment of temperature for 45 feet. the metal retaining the oxygen, and the hydrogen being liberated, English geologists, from experiments made in this country, flamed out of the crater. The enormous scale of volcanic action, incline to the first-mentioned figure. Admitting that the however, precludes the acceptance of this theory, and we most temperature increases because we descend nearer to the heatod look for another cause of volcanio heat. Probably electricity nucleus, these differences might be reconciled by taking into has much to do with it; we know that electric currents traverse consideration local causes, such as the conducting power for heat' mineral lodes, and the Aurora Borealis proves that enormour of the rock in which the mine or well was sunk-which would quantities of electricity are in motion in and about the earth. materially affect the observation--the proximity of the ocean, If a powerful current were condensed by any cause, and forced and other causes. But cases are recorded where the same mine i to pass through a limited space, it would fuse the rock and has altered its temperature very considerably: for example, the supply the great necessary for the existence of a volcano. We Oatfield Mine, in Cornwall, 182 fathoms deep, had a temperature have given a mere outline of these theories, and but very few of of 77° Fahr. while the mine was working. After the abandon- 'the facts by which they are supported. We refer the reader for ment of the workings the temperature was reduced in a few further information to Lyell's “ Principles of Geology," Daubeny months to 66o. In many months after, the equilibrium reached on “ Volcanoes,” and Scrope's “Central France." There are was almost that of the mean temperature of the surface, \ 225 active volcanoes, or rather volcanoes which have been 54° Fahr.

known to erupt within the last 150 years, The most remarkIt is clear that if the original high temperature were dne to able Enropean volcanoes are Vesuvius, Etna, Stromboli, one of the central fire, the mere abandonment of the mine could not the Lipari group, Santorin in the Greek Archipelago, and Heela, have reduced it. Presuming the increase of temperature, as we in Iceland. descend, be due to the approach of the central heat, at a depth The products of volcanoes are of two kinds, lava and ashes. of twenty-five miles a temperature sufficient to fuse such rocks They are not always ejected at once. In the great eruption of as basalt and porphyry must exist.

Vesuvius, A.D. 79, when Herculaneum and Pompeii were buried, The holders of this theory must, therefore, be prepared to the mountain belched forth nothing but ashes, which sa comadmit that our globe has a crust of solid matter, whose thick. 'pletely covered the doomed cities that their very site was unness is represented in Fig. 10, by the breadth of the line c B; known for ages. The first anthentio account of a laya current that is, if A B be the radius of the earth, 4,000 miles, the thick- from Vesuvius is in the year 1036. ness of the curved line, tao of this, will represent the solid crust, Of the quantity of matter ejected by Vesuvius in the eruption all beneath being in a state of molten matter at a high tempera- of 79, history tells us that a shower of sand, lapilli, and pumice ture. This vast quantity of liquid cannot remain at rest, but fell for eight days. Very few of the inhabitants perished in must be traversed by currents, which would cause the tempera- the overwhelming of their cities. The skeletons of two soldiers ture of the whole to be equalised; and it cannot be supposed in the barracks of Pompeii were found chained to the stocks, and that the mere shell would not be broken up and fused, and still in the cellars in a villa in the suburbs of the city seventeen more difficult is it to admit that it is possible that the proximity skeletons were discovered. The form of a Roman lady, with of such a mass at such a temperature would not affect the heat ' an infant in her arms, was imprinted in the rock, but nothing of the earth's crust, which it certainly does not. The answer but the bones remained, which a chain of gold encircled, and given to these objections is, that we do not know the behaviour the rings still adorned the fleshless fingers. Herculaneum is of solids under the influence of a high heat, and at the same buried deeper than Pompeii, but was discovered first by the time submitted to a great pressure; pressure may retard fusion, sinking of a well in 1713, which came down upon the theatre. and that althongh at a high temperature, yet the rocks may not An illustration of the height to which a volcano can eject ashes be molten; but the point of fusion must be reached a few miles was afforded by one of the Mexican mountains in 1835, ashes further down, and therefore the objection is not removed. It is from which fell in Jamaica, 700 miles distant, and must have also urged that the earth's crust is a good non-conductor of heat, been in the air four days. and instances of lava currents are adduced where the surface is In illustration of the rivers of lava which are poured out from solidified and tolerably good, and a few inches below the matter the craters, we may quote the instance given by the Rev. T. is still molten; but the cases are not parallel, the molten lava Coan, of an eruption of Mauna Loa :-"From this yawning is only a dull red, and is at rest; moreover, in due time it will fissure, from two to thirty yards wide, the molten flood rushed cool, whereas the temperature of the earth has not altered since out and spread laterally for four or five miles, filling ravines, the days of Hipparchus, who chronicled certain eclipses. Cal. flowing over plains, covering all from 10 to 200 feet deepculation has found that the times of those eclipses are correct, lava current, including windings, seventy miles long." which proves that the length of the day has not altered for 2,000 The nature of volcanic rocks will be treated of in another years, that is, the rotation of the earth has not increased, which place. it must have done had the earth cooled, for then it would have Before leaving this part of our subject, we must allude to the contracted.

peculiar phenomenon exhibited in the Geysers, in Iceland. The late Mr. Hopkins attempted to calculate the thickness of Whatever part steam may play in a volcanic eruption, there the earth's crust from the influence which the moon exerts upon is no doubt bat that the Geysers owe their action to its the earth, cansing what is called the precessional motion of the agency. The springs are thirty miles from the orater of Heola: earth's pole. He found that, assuming the earth to be a Anid they are springs of hot water, which rise throngh a bed of lava oncleus enclosed by a solid shell, it was necessary that this with such force as to play in the air to a height of 200 feet for should be at least 800 miles thick to cause the calculation to five or six minutes, then the column of water subsides into tho agree with observation.

basin, which is like a volcanic crater, and is in communication The heat in mines, etc., can be well accounted for, without with a cavern beneath. The pipe of the Great Geyser descends this “central heat theory,” by chemical action. Freshly exposed perpendicularly 78 feet, and is from 8 to 10 feet in diameter

, surfaces, especially metallic lodes, are vigorously acted on by The eruption commences with a distant rambling noise

, which the oxygen of the

air; heat is thus developed. This will account comes nearer, the water in the pool becomes agitated, and at for an abandoned mine cooling down to the ordinary temperature length rises in a jet, with clouds of rapoor and a lond explosion.

nun

It is remarkable that an eruption can be caused in some of the noch nichts geben und nichts fertigen, wir sind noch so flein ? springs by throwing stones into their pipes.

noch diýts ghey'-ben oont niýts ferr'-ti-ghen, veer zựnt noch zo klipe ? The explanation of their action will be given by consulting Da nahm der Vater alle trei, das Mägoleir: und die beidet Fig. 11. The water percolates through the rock, and collects in Dah nahm dair fah'-ter ať-lai dry, dass meyyť-line cont dee bi-dem the cavern. Here it is heated by the volcanic fires; on account Buben, und dructe fie an sein Herz und sagte : ge of the length of the pipe the water in the cavern is under great boo-ben, öðnt drück-tai zee an zine herrts šðnt zahdh'- tai : 0 gui. pressure, and hence its boiling point will be several degrees

benfet nicht, daß eure Gabe geringer sei in meinen Augen. above 212° Fahr. When sufficient steam accumulates in the

den'-ket niyt, dass oi'-rai gah'-bai gai-ring'-er zi in mi'-nen ou-ghen, cavern it ejects the water from the pipe, and thus the liquid in

Klopfen doch eure kleinen Herzlein so gut wie die andern the reservoir being relieved of its pressure generates a large Klöp-fen doch oi-rai kli’-nen herrts'-line zo goo't vee dee an'-dern quantity of steam suddenly, producing the eruption. When a

und mein

Vatcrljerz stone is thrown into the pipe it disturbs the water, affecting the dënt mine fah”-ter-herrts' fa'r oiy ai'-lai.

für euch alle. pressure, and giving an opportunity for more steam to be formed,

VOCABULARY. which gives rise to the eruption.

Angebinde, n. keep- Befränzen, to cover, Heim, home.

sake. (anbinden, to with wreaths. Aus der Frembe, from READINGS IN GERMAN.-VII.

bind, attach.) Kissen, to kiss. (Kuß, abroad. (Fremde, Geburt, f. birth.

m. kiss.)

foreign parts.) 7.-Da Angebinde

Blume, f. flower. Boll, full.

Defen, to read.
D488 a n". gai-bin'.dai.

Flechten, to twist, Bote, m. messenger.

Wahr, true. 11 der Geburtstag des Vaters herbeifam, da twine.

Faß, n, cask, barrel. Fertigen, to prepare, Als noon dair gai-boorts'-tach dess fah'-terss herr-by-kahm, dah Kranz, m. wreath. Reif, m. hoop.

make. (fertice jammelten bie trei jüngsten Rinder Blumen, die allerschön. Zuthun, to shnt, close. Wein, m. wine.

ready.) zam-mel-ten dee dry yünk’-sten kyn’-der bloo'-men, doe al·ler-sho'n'- Erwadıon, to awake. Hochheim, n. name of Bube, m. boy, lod, iten und ganz heimlich, und flochten Tie, daß e$ der Pater nicht (wachen, to be a- a place, from which

knave. sten vánt gants hime'-lij, odnt floch- ten zee, dass ess dair fah'-ter niyte wake, to watch.) Rhine wine was Drücken, to press. ab, zum

schönen Strange und fonnten die ganze Nacht fein Blob, bare, merely. called Hock, Gedenfen, to think, rezah, tačóm shő-nen kran'-tsai dönt kon'-ten dee gan'-tse nacht kine Hören, to hear. Tanzen, to dance. member. (bentes, fuge zuthun.

Tragen, to bear, carry. Gesang, m.song, hymn. to think.) cu mi teoo-toon.

Ocie, softly.

Blatt, n. leaf, sheet Gabe, J. gift. #1! ter Tag erwachte, gingen sie alle brei in das sama Engel, m. angel.

of paper.

Gering, trifling. Alas dair tac err-vach'-tai, ging'-en zee al-lai dry in dass kem'neticin mit bloßen Füichen, daß es der Vater nicht höre,

8.-Der hungrige Ara ber. mer-line mit blo'-ssen fa'ss'-yen, dass egs dair fah'-ter niyt hö'-rai,

Dair hoong'-ri-gai a'-ra-ber, trugen

tert

Blumenfranz alle drei, und legten ihn Gin Araber wat verirrt in der Wufte. Zwei Tage harte Ant troo'-ghen dain bloo'-men-krants al'-lai dry, öðnt leyy'-ten een Ine a'-ra-ber vahr ferr-irrt in dair vü"-stai. Tsvi tah'.gai hat-tai quftes Baters Bett ganz

leise, Daß es ber Dater nicht er nichts zu essen und war in Gefahr, Hungers ju fter caf dess fah'-terss bet gants li'-zai, dass ess dair fah’-ter niyt eyr nỉýts tsoo ess'-sen gånt vahr in gai-fahr', hdong'-e

'-ers tsoo shtert'. merle Der Vater merfte es wohl, aber er that, als

ben, als er endlich eine von den Wassergruben antraf, mert kai. Dair fah’-ter merrk’-tai ess vole, ah'-ber eyr taht, alss ben, alss eyr ent-L'y i'-nai fon dain vass'-ser-gtoo'-ben an'-trabf, an Foliefe.

benen die Reisenden ihre Kameele tränfer. Hier faber óp eyr shlee'-fai.

dey'-nen dee ri'-zen-den eeʻ-rai ka-mey'-lai treng-ken. Here zah eyr Wat als es Morgen war, ba fam ter Vater und auf dem Sande einen kleinen ledernen Sack liegen.

(Hott Pei Odat alss ess noon mor-ghen vahr, dah kahm dair fah'-ter öðnt ouf daim zan'-dai i'-nen kli'-nen ley'-der-nen zack lee'-ghon. St zi hatte den schönen Blumenfranz und Tagte : Wo sind die gelobt, sagte er, al8 er ihn aufhob und

anfühlte ; das hat'- tai dain sho'-nen blooʻ-men-krants dont zahti-tai : Vo zint dee gai-lo'pt', zahch'-tai eyr, alss eyr een ouf'-hope dont an'-fü’l-tai; dass

Grzekein, die mich befrånzet haben in der Nacht, da ich sind, glaube id), Datteln oder Nüsse; wie will ich mich an ihren sog'-ai line, dee miý bai-kren'-tset hah'-ben in dair nacht, dah lý zint, glou'-bai lý, dat-teln o’-der nüss'-sai; vee vill rý mlý an ee'-nen hej! Und die Kinder kamen und hingen an ihm, füften erquiden und laben. In dieser süßen Hoffnung öffnete Leef!

cont dee kin'-der kah'-men öðnt bing'-en an eem, küss'-ten err-quick'-ken oðnt lah'-ben. In dee'-zer zü''-esen hof-noðnk öt- nai-tai REA Sater und waren voll Freude.

den Sack, sah was enthielt und rief voll Tranrigteit dain iahter jnt vah'-ren föll froi'-dai.

eyr dain zack, zah vass eyr ent-heelt sõnt reef fou tron-rig-kito lain ein Mann, ein Bote, ber brachte ein feines que : Ach, ef sind nur Perlen. Dah kahm ine man, ine boʻ-tai, deyr brach-tai inefi'-ness ouss: ach, ess zỉnt voor perr'-len. runtes Fäßlein mit Reifen; darinnen war schöner Wein von

VOCABULARY. rodd'-dess fess'-line mit ri-fen; da-rin'-nen vahr sho'-nervine fðn het beim

Hungrig, hungry. Tränken, to give to laben, to comfort. Das Herz bes Vaters zu erfreuen. Da

drink. Sich verirren, to stray,

Joffnung, f. hope. Hoo-hime, dass herrts dess fah'-terss tsoo err-froi'-en. Dah vahr

to lose one's self. Petern, leather, of (hoffen, to hope, to ter Bater erfreuet, ale er sab, daß der alteste Sohnes

leather, Wüste, f. desert.

wish.) dair fah'-ter err-froi'-et, alss eyr zah, dass dair el'-tai-stai zone ess

Wefahr, f. danger. Loben, to praise. Enthalten, to contain, sirnbet, und die Kinder tanzten um

ben Vater und tas

Entlich, at last. Aufheben, to lift up. hold, to keep from. gau-zen-det, dont dee kin'-der tants'-ten dóm dain fah'-ter öðnt dass Grube, f. pit. Anfühlen, to feel. Boll, full (of). Reflein

Antreffen, to find, meet. Glauben, to believe. Traurigfrit, f. sadness. iera line.

Neisende, m. travel- Dattel, f. date.

(-leit, affix, -ness.) trat ter Vater an den Tisch und fand ein fein ler.

Grquiden, to refresh. ! Perle, f. pearl. Dahr-Dahd' traht dair fah'-ter an dain tish ont fant ine fine grad Blatt, darauf war ein schöner und frommer Gesang

KEY TO EXERCISES IN LESSONS IN GERMAN. ETO-ss blnt, dah-rout vahr ine sho'-ner dönt frðm'-mer gai-sank'

EXERCISE 116 (Vol. II., page 247). Sen berri goeiten Sohne, der aus der Fremde heimgefommen 1. I am nineteen years old, and in my twenty-third year I shall go făn daimn tsvi-ten zo'-pai, deyr ouss dair frem'-dai hime'-gai-kom-men with my father to England. 2. My eldest brother had invited twentymer. Und als der Vater c$

3. The company las, ba lächelte

five persons, among whom nearly half were married,

und die Tahr. But alss dair fah'-ter ess lahss, dah ley'-yel-tai eyr cont dee

left us at a quarter to twelve. 4. Columbus discovered Ameria in Ibráner fielen auf das Blatt.—Da saben die drei Kleinen ren

the year 1492. 5. A dozen contains twelve (pieces), and a pound contrey'. Den fee'-len ouf dass

tains thirty half ounces (German measure). 6. We bought three casks blat.-Dah zah'-en dee dry kli'-nen dain

of oil, two pairs of shoes, and seven yards of cloth. 7. Thousands of Bater an und sagten : Lieber Vater, nicht wahr? Wir fönnen Germans emigrate to America. 8. I have sold a hundred pens for fah -ter an oont zahch-ten: Lee'-ber fah'-ter, nyyt vahr? veer kön-nen

half a dollar. 9. Shakespeare's birthday is the twenty-third of April

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It has long been a theory pertinaciously adhered to, that the when the chemical action was exhausted. Moreover, we must centre of the earth is now in a state of molten incandescence, remember that air in a condensed state acquires a lower specific and that all volcanoes derive their igneous action from the heated heat, that is, its capacity for containing heat is decreased; hence centre. In conjunction with the existence of burning moun. an increment of heat will have a much greater effect in increas. tains, another fact is adduced, which appears to give great ing the temperature at the bottom of a mine than on the surface. weight to the supposition. It is generally found that in In the case of well-waters, the chemical action is induced by the descending the crust of the earth the temperature increases. 'gases they hold in solution acting upon the rocks through which Numerous observations in mines and artesian wells have been they percolate, and on the sides of the subterranean reservoirs made, and it is concluded that in England the thermometer in which they collect. Sir Humphry Davy, Daubeny, and others, rises 1° Fahr. for every 55 feet descended.

ascribe even volcanic heat to chemical action. The discoverer of The reader must not suppose that this increase is at all the metals of the alkalies, potassium and sodium, supposed that at uniform; indeed, Kupffer, from very extensive comparisons, the base of burning mountains were vast deposits of these metals; infers that the increase is 1° Fahr. for every 37 feet, while that when water found its way to the metal it became decomposed, Cordier gives the same augment of temperature for 45 feet. the metal retaining the oxygen, and the hydrogen being liberated, English geologists, from experiments made in this country, flamed out of the crater. The enormous scale of volcanic action, incline to the first-mentioned figure. Admitting that the however, precludes the acceptance of this theory, and we must temperature increases because we descend nearer to the heated look for another canse of volcanic heat. Probably electricity nucleus, these differences might be reconciled by taking into has much to do with it; we know that electric currents traverse consideration local causes, such as the conducting power for heat mineral lodes, and the Aurora Borealis proves that enormous of the rock in which the mine or well was sunk-which would quantities of electricity are in motion in and about the earth. materially affect the observation---the proximity of the ocean, If a powerful current were condensed by any cause, and foroed and othor causes. But cases are recorded where the same mine to pass through a limited space, it would fuse the rock and has altered its temperature very considerably : for example, the ! supply the great necessary for the existence of a volcano. We Oatfield Mine, in Cornwall, 182 fathoms deep, had a temperature have given a mere outline of these theories, and but very few of of 77° Fahr. while the mine was working. After the abandon the facts by which they are supported. We refer the reader for ment of the workings the temperature was reduced in a few further information to Lyell's “ Principles of Geology," Daubeny months to 66o. In many months after, the equilibrium reached on · Volcanoes,” and Scrope's “Central France." There are was almost that of the mean temperature of the surface, ( 225 active volcanoes, or rather volcanoes which have been 54° Fahr.

known to erupt within the last 150 years. The most remarkIt is clear that if the original high temperature were due to able European volcanoes are Vesuvius, Etna, Stromboli, one of the central fire, the mere abandonment of the mine could not the Lipari group, Santorin in the Greek Archipelago, and Hedla, have reduced it. Presuming the increase of temperature, as we in Iceland. descend, be due to the approach of the central heat, at a depth The products of volcanoes are of two kinds, lava and ashea. of twenty-five miles a temperature sufficient to fuse such rocks . They are not always ejected at once. In the great eruption of as basalt and porphyry must exist.

Vesuvius, A.D. 79, when Herculaneum and Pompeii were buried, The holders of this theory must, therefore, be prepared to the monntain belched forth nothing but ashes, which sa comadmit that our globe has a crust of solid matter, whose thick- pletely covered the doomed cities that their very site was 12ness is represented in Fig. 10, by the breadth of the line C B; 'known for ages. The first anthentic account of a laya current that is, if A B be the radius of the earth, 4,000 miles, the thick from Vesuvius is in the year 1036. ness of the curved line, são of this, will represent the solid crust, Of the quantity of matter ejected by Vesuvius in the eruptica all beneath being in a state of molten matter at a high tempera- of 79, history tells us that a shower of sand, lapilli, and pumice ture. This vast quantity of liquid cannot remain at rest, but fell for eight days. Very few of the inhabitants perished ir must be traversed by currents, which would cause the tempera- the overwhelming of their cities. The skeletons of two soldier: ture of the whole to be equalised; and it cannot be supposed ' in the barracks of Pompeii were found chained to the stocks, and that the mere shell would not be broken up and fused, and still in the cellars in a villa in the suburbs of the city seventeen more difficult is it to admit that it is possible that the proximity skeletons were discovered. The form of a Roman lady, with of such a mass at such a temperature would not affect the heat an infant in her arms, was imprinted in the rock, but nothing of the earth's crust, which it certainly does not. The answer but the bones remained, which a chain of gold encircled, ano given to these objections is, that we do not know the behaviour the rings still adorned the fleshless fingers. Herculaneum i of solids under the influence of a high heat, and at the same buried deeper than Pompeii, but was discovered first by thì time submitted to a great pressure; pressure may retard fusion, sinking of a well in 1713, which came down upon the theatre and that although at a high temperature, yet the rocks may not' An illustration of the height to which a volcano can eject ashe be molten ; but the point of fusion must be reached a few miles was afforded by one of the Mexican mountains in 1835, ashe further down, and therefore the objection is not removed. It is from which fell in Jamaica, 700 miles distant, and must har also urged that the earth's crust is a good non-conductor of heat, | been in the air four days. and instances of lava currents are adduced where the surface is In illustration of the rivers of lava which are poured out frot solidified and tolerably good, and a few inches below the matter the craters, we may quote the instance given by the Rev. ! is still molten; but the cases are not parallel, the molten lava Coan, of an eruption of Mauna Loa :- "From this yawnik is only a dull red, and is at rest; moreover, in due time it will fissure, from two to thirty yards wide, the molten flood rishe cool, whereas the temperature of the earth has not altered since out and spread laterally for four or five miles, filling ravinen the days of Hipparchus, who chronicled certain eclipses. Cal. flowing over plains, covering all from 10 to 200 feet deepculation has found that the times of those eclipses are correct, lava current, including windings, seventy miles long." which proves that the length of the day has not altered for 2,000 The nature of volcanic rocks will be treated of in anothi years, that is, the rotation of the earth has not increased, which place. it must have done had the earth cooled, for then it would have Before leaving this part of our subject, we must allade to th contracted.

peculiar phenomenon exhibited in the Geysers, in Icelan The late Mr. Hopkins attempted to calonlate the thickness of Whatever part steam may play in a volcanic eruption, the the earth's crust from the influence which the moon exerts upon is no doubt but that the Geysers owe their action to i the earth, cansing what is called the precessional motion of the agency. The springs are thirty miles from the crater of Hecla earth's pole. He found that, assuming the earth to be a Anid they are springs of hot water, which rise through a bed of le nucleus enclosed by a solid shell, it was necessary that this with such force as to play in the air to a height of 200 foet i should be at least 800 miles thick to cause the calculation to five or six minutes, then the column of water subsides into t agree with observation.

basin, which is like a volcanio crater, and is in communicati The heat in mines, etc., can be well accounted for, without with a cavern beneath. The pipe of the Great Geyser desceu this "central heat theory,” by chemical action. Freshly exposed perpendicularly 78 feet, and is from 8 to 10 feet in diamet surfaces, especially metallic lodes, are vigorously acted on by The eruption commences with a distant rumbling noise, wiu the oxygen of the air; heat is thus developed. This will account comes nearer, the water in the pool becomes agitated, and for an abandoned mine cooling down to the ordinary temperature length rises in a jet, with clouds of vapour and a loud explosi READINGS IN GERMAN.

2

leise,

ihre

It is remarkable that an eruption can be caused in some of the noch nicht geben

und nichts Fertigen, wir sind noch so flein ? springs by throwing stones into their pipes.

noch niýts ghey'-ben oont niýts ferr'-ty-ghen, veer zint noch zo klipe ?
The explanation of their action will be given by consulting Da nahm ber Vater alle trei, das Mägdleir: und die beiden
Fig. 11. The water percolates through the rook, and collects in Dah nahm dair fah'-ter as-lai dry, dass meyyť-line dont dee bi-den
the carernHere it is heated by the volcanic fires; on account

Buben, und brüdte fie an sein Herz und sagte : D ge
of the length of the pipe the water in the cavern is under great boo’-ben, öðnt drück-tai zee an zine herrts ont zahai-tai : O gai.
precure, and hence its boiling point will be several degrees

benfet nicht, daß eure Gabe geringer sei in meinen Augen.
abore 212° Fahr. When sufficient steam accumulates in the den'-ket niýt, dass oi'-rai gah'-bai gai-xing'-er zi jn mi’-nen ou’-ghea.
cateru it ejects the water from the pipe, and thus the liquid in

Klorfen doch eure kleinen Herzlein

so gut wie die

andern the reservoir being relieved of its pressure generates a large Klšp'-fen doch oi'-rai kli’-nen herrts'-line zo goo't vee dee an’-dern quantity of steam suddenly, producing the eruption. When a

und mein

Baterherz
store is thrown into the pipe it disturbs the water, affecting the ont mine fah”-ter-herrts fü’r oiy ai-lai.

für euch alle.
presure, and giving an opportunity for more steam to be formed,

VOCABULARY. stich gives rise to the eruption.

Angebinde, n. keep- Defrånzen, to cover | Heim, home.

sake. (anbinden, to with wreaths. Aus der Fremde, from

bind, attach.)
READINGS IN GERMAN.-VII.

abroad. (Fremde,
Küssen, to kiss. (Ruß,
Geburt, f. birth.

m. kiss.)

foreign parts.) 7.- Das Angebinde

Blume, f. flower. Coll, full.

Lesen, to read.
D488 a 1"-gai-bin'-dai.

Flechten, to
twist, Bote, m. messenger.

Wabr, true.
Hmun der Geburtstag
Vaters herbeifam, ta twine.

Faß, n, cask, barrel. Fertigen, to prepare,
Als noon dair gai-bõõrts'-tach dess fah'-terss herr-by'-kahm, dah Kranz, m. wreath. Reif, m. hoop.

make. (terrier
memelten die erei jüngsten Kinder Vlumen, tie allerschön- Zuthun, to shut, close. Wein, m. wine.

ready.)
zam:bel-ten dee dry yünk'-sten kin'-der bloo'-men, dee al'.ler-shö’n’- Grwachen, to awake. Hochheim, n. name of Bube, m. boy, lod,
in nat ganz þeimlich, und Flechten sie, daß (8 ter Vater nicht

(wachen, to be a- a place,from which knave.
stea sifat gants hime'-liý, odnt flodi-ten zee, dass ess dair fah'-ter niyte wake, to watch.) Rhine wine was Drücken, to press.
idonen Kranje
und fonnten die
ganze Nacht kein Bloß, bare, merely. called Hock, Gedenfen, to think, re-

member.

Tanzen, to dance. mah, is sboʻ- Den kran'-tsai dont kõn'-ten dee gan'-tse nacht kine Hören, to hear.

(denho,

to think.)

Tragen, to bear, carry. Gesang,m.song, hymn.
degguthun
-mi tsoo'-toon.

Lehe, softly.

Blatt, n. leaf, sheet Habe, I. gift. 14 ta Tag

of paper. erwachte, gingen alle trei in das Käms

Engel, m. angel.
fie

Gering, trifling.
Ales dair tad, ert-vach-tai, ging'-en zee al-lai dry in dass kem'-
hin mit bloken Füschen, daß es ber Vater nicht höre,

8.- Der hungrige Araber.
ser-lize mit blo-ssen fü'ss'-yen, dass egs dair fah'-ter niýt hö'-rai,

Dair hỗ ở ng”-ri-gai 2'-ra-ber. trugen ten Blumenfranz alle trei, und legten

ibn Gin Araber Ipar verirrt in der Wüste. Zwei Tage hatte kot tron'-ghen dain bloo'-men-krants al-lai dry, ošnt leyy'-ten een Ine a'-ra-ber vahr ferr.irrt in dair vü"-stai. Tsvi tah'-gai hat-tai Baters Bett ganz бар c8 ber Vater nicht

er nicht zu

effen
und war in Gefalır, Gungers zu

ftet
al dess fah'-terss bet gants li'-zai, dass ess dair fah'-ter nýyt eyr niýts tsoo ess'-sen Jónt vahr in gai-fahr', höõng”-ers tsoo shteri'.
Serde Der Bater merfte es wohl, aber er that, als

ben, als er endlich eine von Wassergruben antraf, Dair fah'-ter merrk'-tai ess vole, ah'-ber eyr taht, alss ben, alss eyr ent-Ivý i-nai fon dain vass'-ser-grooʻ-ben an'-trabf, an thefe

denen die Reisenden

Rameele trånfer. Hier saber ha eti shlee-tai,

dey'-nen dee ri'-zen-den ee'-rai ka-mey'-lai treng-ken. Here zah eyr cs

Morgen war,
nun
ba fam ter Pater
auf dem Sande einen kleinen lebernen

Gott Tei
Sack liegen.

Got zi

ouf daim zan'-dai i'-nen kli'-nen ley'-der-nen zack leoʻ-ghen.
Wat alas esg noon mor-ghen vahr, dah kahm dair fah'-ter öõnt
Fatos e iconen Blumenfranz

und
sagte : Wo sind die
gelobt, sagte er, als

das er ihn aufhob und

anfühlte ; zi din shð-nen bloo-men-krants šðnt zahch'-tai : Vo zint dee gai-lo'pt', zahdh'- tai eyr, alss eyr een ouf'-hope oönt an'-fa’l-tai ; dass Espirin, die mich befrânzet haben in der Nacht, da ich sind, glaube id), Datteln oder Nässe ; wie will ich mich an ihren abine, dee mlý bai-kren-tset hah'-ben in dair nacht, dah lý zint, glou'-bai lý, dat-teln oder nüss'-sai; vee vill lý mlý an te'-nen

lind tie Kinder tamen und hingen an ihm füßten erquiden und laben. In dieser süßen Hoffnung öffnete

dat dee kin'- der kah'-men dont bing.en an eem, küss'-ten err-quick-ken oờnt lah'-ben. In dee'-zer zü''-ssen hot-noðnk of'- nai-tai Sator und waren voll Freude.

den Sacf, sah was enthielt und rief voll Traurigteit tih ter bont yah'-ren föll froi'-dai.

eyr dain zack, zah vass eyr ent-heelt 8ðnt reef fou trou'-riy-kito fart ein Mann, ein Bote,

brachte
ein feines

auß: Ach, es sind nur Perlen.
Dab tahin ine man, ine boʻ-tai, deyr brach-tai inefi'-ness ouss: ach, esszint noor perr'-len.
Fäßlein mit Reifen; darinnen schöner Wein von

VOCABULARY.
Pisodess fess-line mit ri-fen; da-rin-nen vahr shoʻ-ner vine fðn

Hungrig, hungry. Trånfen, to give to Laben, to comforti.
Herz Vaters zu erfreuen. Da war

Sich verirren, to stray, drink.

Koffnung, $. hope. - berne, dass herrts dess fah'-terss tsoo err-froi'-en. Dah vahr

to lose one's self. | Ledern, leather,

of

(hoffen, to hope, to erfreuet, ala et sah, daß der älteste Sohn es

Wüfte, f. desert.

leather.

wish.) et fab-ter err-froi'-et, alss eyr zah, dass dair el-tai-stai zone ess

Gefahr, f. danger. loben, to praise. Enthalten, to contain, und die Kindertanzten

ben Vater und tas

Endlich, at last. Aufheben, to lift up. hold, to keep fron. 2-det, dúnt dee kin-der tants'-ten öðm dain fah’-ter 8ðnt dass Orube, f. pit. Anfühlen, to feel. Voll, full (of).

Antreffen, to find, meet. Glauben, to believe. Traurigkeit, f. sadness.
Reisende, m. travel. Dattel, f. date.

(-leit, affix, -nesa.)
trat
ter
Vater ben Tisch und fand ein fein ler.

Erquiden, to refresh. / Perle, f. pearl. Oshi-sabiti trabt dair fah'-ter an dain tish đðnt fant ine fine ja Blatt, tarauf war ein schöner und frommer Gesang

KEY TO EXERCISES IN LESSONS IN GERMAN. as blat, dah-roaf vahr ine sho'-ner dont frðm'-mer gai-sank'

EXERCISE 116 (Vol. II., page 247). poveiten Sobne, der aus der Fremde heimgcfommen 1. I am nineteen years old, and in my twenty-third year I shall go - iz 17-ten zo'-nai, deyr ouss dair frem'-dai hime'-gai-kom-men with my father to England. 2. My eldest brother had invited twenty

3. The company ad als Bater lad, ba lächelte und die five persons, among whom nearly half were married.

4. Columbus discovered America in

left us at a quarter to twelve. Wat alsa dair fah'-ter ess lahss, dah ley'-yel-tai eyr dont dee

the year 1492 5. A dozen contains twelve (pieces), and a pound confielen auf das Blatt.-Da fahen die brei Kleinen ten

tains thirty half ounces (German measure). 6. We bought three casks 12 teeles ouf dass blat. --Dah zah'-en dee dry kli'-uen dain

of oil, two pairs of shoes, and seven yards of cloth. 7. Thousands of Lieber sagten: Vater, nicht wahr? wir können

8. I have sold a hundred pens for

Germans emigrate to America, -es as cut zahoi'-ten: Lee'-ber fah'-ter, niýt vahr ? veer kõn'-nen hulf a dollar. 9. Shakespeare's birthday is the twenty-third of April

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