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POTASSIUM.

EXERCISE 92 (Vol. II., page 10).

The usual method of obtaining this compound is by boiling 1. Combien ma maison vaut-elle ? 2. Elle vaut une vingtaine de one part of potassium carbonate with twelve parts of water, mille francs. 3. Ce cheval-lå vaut-il autant que celui-ci ? 4. Ce cheval and adding slaked lime made from two-third parts of quickci vaut deux cents piastres, et celui-là trois cents. 5. Vaut-il la peine lime. The reaction is d'écrire à M. votre frère ? 6. Il n'en vaut pas la peine. 7. Vaut-il

K,OCO + H,OCaO = 2 (HKO) + CaoCog. la peine de sortir, quand on n'a pas envie de se promener? 8. II n'en vaut pas la peine. 9. Vous convient-il d'écrire deinain à mon The calcium carbonate (chalk) sinks to the bottom, while the frère ? 10. Il ne me convient pas de lui écrire. 11. Vous sied-il de clear liquid is decanted and evaporated without contact with the me reprocher ma négligence ? 12. Il me sied de vous blâmer, quand air. The residue may be cast into sticks, but the fusion should vous le méritez. 13. De combien cet homme est-il riche ? 14. Je be carried on in silver vessels. ne puis vous le dire au juste, d'une cinquantaine de mille francs. 15.

It deserves the name “caustic" from its severe action on Ce drap est-il bon ? 16. Non, Monsieur, il ne vaut rien. 17. Votre

animal tissues. fusil vaut-il autant que le mien? 18. Oui, Monsieur, il vaut davantage. 19. Voulez-vous aller chez mon père? 20. Non, Monsieur, j'ai autre

Potassium Carbonate (K,000.).—This is imported from the chose à faire. 21. Vaut-il mieux aller au marché de bonne heure que forests of Russia and America in large quantities as pot-ashes or tard ? 22. Il vaut mieux y aller de bonne heure. 23. Combien votre pearl-ashes. cheval peut-il valoir ? 24. Il ne vaut pas beaucoup, il est très-vieux, To render it pure it is calcined like potassic hydrate. It is 25. Votre montre est-elle meilleure que la mienne ? 26. Elle ne vaut a strong alkali, and if exposed long enough to the air, absorbs pas grand'chose, elle ne va pas. 27. Ce livre vaut-il deux francs ? 28. moisture and becomes an oily liquid. By passing a current of Il en vaut un, au plus. 29. Avez-vous demandé à votre sour combien carbonic dioxide through a solution of this salt, one of the vaut ce livre ? faire ? 32. 1 vous faut parler à M. votre père. 33. Lui faut-il de atoms of K may be replaced by one of H, forming hydric potasl'argent ?. 3.4... lui non faut. 5. Na-t-il pas vendu son cheval? 36. sium carbonate *} Co,. This salt is not so soluble as the l'a vendu, mais il ne valait pas .

carbonate, and is almost neutral, having no effect on reddened

litmus paper. LESSONS IN CHEMISTRY.-XVIII. Potassium Nitrate, Nitre, or Saltpetre (KNO,) is found as an CLASS I.--METALS OF THE ALKALIES.

efflorescence upon the soil in certain districts in the East Indies. The soil favourable to its production is of a loose limy nature,

mixed with decomposing felspar, which contains potash, and of SYMBOL, K-ATOMIC WEIGHT, 39-1—SpecifIC GRAVITY, 0865—MELTING necessity there must be present more or less organic matter. POINT, 62.50

The process by which the salt is produced is called “nitrificaSIR HUMPHRY Davy, in 1807, included this metal in the list tion," and is little understood. It is supposed that the decomof brilliant discoveries which he made by means of the electro- posing organic matter which contains nitrogen gives off ammonia; lytic action of the galvanic current. He slightly moistened that this ammonia becomes oxidised into nitric acid, which with some hydrate of potash, in order to render it a conductor, and the potash forms nitre. In Sweden, the farmers have * nitre then applied to it the poles of a strong battery. At the nega- plantations,” that is, they throw all the refuse of their farms, ete, tive wire the metal potassium appeared.

into a heap, which they continually turn to expose it to the air. The preparation of the metal may be conducted with much After three years, the bed is lixiviated, or washed with water. less expense by either of the following processes :

To this water pearl-ash is added, by which the nitrates of lime 1. Melted potassic hydrate is allowed to run over iron turn- and magnesia are decomposed, and the nitrate of potash formed. ings in a bent gun-barrel, which is raised to a considerable Upon evaporation the nitre crystallises out, the insoluble cartemperature in a charcoal furnace. The iron deprives the bonates having fallen. potash of its oxygen, and the metal potassium passes over in Saltpetre contains nearly one-half its weight of oxygen, with vapour, which is condensed in naphtha.

which it readily parts when in contact with carbon. To this 2. The present mode of procuring the metal, however, was property it owes its commercial value, it being the chief ingreinvented by Curandau. It consists in intimately mixing 69 dient of parts of potassic carbonate and 12 parts of carbon. This

Gunpowder, a compound which is said to have been discovered mixture is heated in a crucible, and then the porous mass is about 1336 by a certain Cordelier monk of Breslau, named broken into small pieces and introduced into an iron retort, Berthold Schwartz. This is unlikely, for the Arabians and which is submitted to a high heat.

Chinese had used an explosive substance for many centuries, K,000 + 2C = 3C0 + 2K

and even Roger Bacon, who died about 1294, in his treatise explains the action and intimates that the mixture is entirely “De Nullitate Magiæ,” gives a receipt for making a kind of converted into carbonic oxide and potassium. The delivery tube gunpowder

, Our English powder consists of 75 parts of nitre, 15 from the retort projects a few inches out of the furnace, and carried on at the Government mills at Waltham Abbey is the

of charcoal, and 10 of sulphur. The process of manufacture dips into a receiver of naphtha, which is kept cool by being sar

following:rounded by water. Properties.--At ordinary temperatures potassium is a soft The charcoal is that of alder-wood; the proper proportion of

The ingredients are with great care procured perfectly pure. metal. When cut, it is found to be of a white colour. It has each to make a “charge" of 52 lbs. is taken and grannd great affinity for oxygen, and will at a red-heat deprive almost separately into impalpable powder. The powders are then any gas of that element. As we have seen, it can even decom. mixed, and water is added to make them into a paste; this is pose water, the heat evolved in the action being sufficient to set placed beneath two broad wheels fixed on the same axle, one of fire to the escaping hydrogen, the flame of which is tinged by which rolls within the other, on a smooth iron plate. By this the beautiful purple colour which is characteristic of the “ potash " incorporating mill” the ingredients are thoroughly mired, and flame."

Potash is the widely-diffused oxide of potassium. It takes the paste is then submitted to a pressure of 70 tons on the its name from the fact that it is obtained from the ashes” of like a piece of metal. This cake is next broken by spiked

square inch; the “press cake" thus produced rings, when struck, the wood with which the “pot” has been boiled. Plants have rollers, and the grains sifted on sheets of parchment, perforated the power of abstracting potash from the soil. It is a con- with different sized holes; these being placed one above the other, stituent of granite rocks, from which all soils are originally the large grains are delivered into their proper receptacle from derived. The wood-ashes when washed have their potash dis- the top sieve, the finest grains being found on the lowest. The solved by the water, and upon evaporating this solution "Pearl- powder in this condition is of a dull leaden colour, and is glazed ash” is obtained, which is really not potash, but an impure by being placed in a barrel which revolves very rapidly on its carbonate of potash, and forms one of the sources from which axis; the grains polish each other by mutual friction; occasion our potassium and its salts are derived. Potassic Hydrate, op " Caustic Potash(HKO).-If thin slices the powder less liable to contract damp.

ally a little black-lead is added. This latter process renders of potassium be exposed to dry oxygen, Potassium Monoxide

When ignited the following reaction occurs :(K,0) is formed--a white, brittle substance. It absorbs moisture with avidity, forming potassic hydrate (HKO), in which it will

2KNO, + 3C + S = 6,8 + 3C0 +2N; be seen that one atom of K has been replaced by one of H. that is, the solid becomes entirely gas, with the exception of the

Borax

LITHIUM.

KS (potassium sulphide), which is dissipated in smoke. allowed constantly to trickle; this water absorbs the gas, and is These products of the combustion occupy, at the high tempera- the source of the hydrochloric acid of commerce; when the action ture of the explosion, about 1,400 times the volume of the becomes sluggish, the hydrosodic sulphate is raked out and expowder.

posed to a higher heat in a chamber of brick-work, the fluo Pulvis fulminans is a mixture of 3 parts of nitre, 2 potassium from which also enters the vertical flue. By this means tho carbonate, and 1 sulphur, which, when heated on an iron shovel | atom of hydrogen which is associated with the sodic salt is antil fusion takes place, explodes violently.

driven off, thusOf the other salts which potash makes with every acid Potas

HNSO. + NaCl = Na,so, + HCI. sium Chlorate (KCIO,) is the most important. It is procured by submitting a mixture of potassium carbonate and slaked This sodium sulphate which is the result of this process is lime, moistened, to the action of chlorine gas; the chlorate known as salt-cake. formed is separated by lixiviation and crystallisation.

2. Soda-ash Process.--The salt-cake is ground up with an Potassium combines with the halogens and sulphur, when equal weight of chalk (CaoCo.) and half its weight of coal. heated with them, forming many salts of great medicinal The mixture is then submitted to the heat of a “reverberatory' value.

furnace--that is, it is spread on a hearth, over which the flamo All the salts of potassium, if introduced on a platinum wire of the furnace passes. The mixture melts, and these two reacinto the reducing flame of the blowpipe, impart to the flame a

tions take place :purple tinge; and with bichloride of platinum, a concentrated

1. Na,so, + 4C = Na,s + 4CO. solation containing potash gives a yellow precipitate.

2. Nags + Caoco, = Na,oco, + Cas. SODIUM

The calcium sulphide and the other impurities being insoluble, STYBOL, Na-COMBINING WEIGHT, 23-SPECIFIC GRAVITY, 0.97—

the sodium carbonato, or soda-ash, is washed out. Soda MELTING POINT, 980.

crystals, used in washing, are got by saturating a solution with The discovery of sodium was immediate upon that of potassium. soda-ash, and allowing it to crystallise. The metal is obtained frm sodium carbonate by an analogous

The Bicarbonate of Soda, which is used in effervescing drinks,

Na method to that which produces potassium; it distils over with is Hoco,, and is made by exposing soda crystals to the carbonic oxide, with which, unlike potassium, it does not combine.

action of carbonic acid. Sodium is now prepared in large quantities, for it is used in

Sodium Hyposulphide (Na,OH,OH,O, + 4H,O) has the power the extrication of magnesium and aluminum from their salts. of dissolving some silver salts ; hence its employment in photoWhen thrown on water it decomposes it, but the action, unless graphy. Sodium is an element of these salts :the water be thickened by starch paste, is not sufficiently

Sodium phosphate Na, HPO, + 12H,0. violent to ignite the escaping hydrogen.

Microcosmic Salt | NaNH,HPO,. Its compounds are widely distributed in Nature. Indeed,

= Na,B,O, + 101,0. the “ spectrum analysis " would indicate that the presence of The other sodium salts are of less importance. sodium, in some form, is all but universal. The sea is its great repository, its waters containing 3 per cent. of sodium chloride, or common salt.

SYMBOL, Li.-COMBINING WEIGHT, 7-SPECIFIC GRAVITY, 0-59— The Oxide of Sodium, or "caustic" soda (Na,0), may be pro

MELTING POINT, 180°. cured in a manner analogous to that which gave potash, and

Lithium is the lightest of the metals. The spectrum analysis the same is the case with the hydrate that is, by the action declares it is widely distributed. By this means it has been of milk of lime on carbonate of soda.

detected in most waters, in milk, and in tobacco. Lithium Sodium Nitrate (NaNO3), or Chili Saltpetre, is found in that chloride imparts to filame a brilliant crimson tinge. The metal country in large quantities. Indeed, the natives of Chili and itself is obtained by decomposing this salt by means of the Pera build their houses of blocks of the salt. It cannot be galvanic current. used in the manufacture of gunpowder for it is deliquescent;

Lithia (Li,O) stands between the alkalies and the alkaline however, it is of indirect use, for nitre may be made from it.

earths. Sodium Chloride (NaCl may be procured from the sea by

AMMONIUM (NH) has been noticed. evaporation, but is generally supplied by salt mines, the prin.

RUDIBIUM and CÆSIUM owe their discovery to the spectrum cipal of which are in Cheshire, Poland, and Spain. The Polish analysis. Rudibium takes its name from the red line its mine of Wieliczka is a mass of salt 500 miles in length, 20 compounds form in the spectrum. Cæsium gives two bluo in breadth, and at least 1,200 feet thick, a quantity suffi- lines. These metals closely resemble potassium. Their salts eient to supply the culinary demands of the world for ages. are widely distributed, but in very small quantities. As yet Salt when crystallised

is rock salt, or sal gem; the crystals they have no commercial and but little chemical interest. are cubic.

Sodium Sulphate (Na,80, + 10 H,0), or Glauber Salt, is re-
markably efflorescent; that is, it gives off its water and LESSONS IN GREEK.—XVI.
crumbles to powder. It has a saline bitter taste, and is used

COMPARISON OF ADJECTIVES.
as a medicinal purgative.
Its preparation will be referred to in the making of

SUPERLATIVE (from super, above, beyond, and latus, carried) is Sodium Carbonate (Na,000,), which constitutes the most which signifies the greatest degree or amount of the quality

in grammar applied to adjectives when they are in that form important of chemical manufactures. It is used in the manufacture of glass and soap, in calico printing, in softening hard the quality, is called the comparative; and the simple state

described by them. The degree below, or an inferior degreo of waters, and in the preparation of all the other salts of soda. Formerly it was procured, as potash is still, from the ash of the positive, suceet-er the comparative, and sweet-est the super

of the adjective is named the positive: for example, sweet is certain plants, but this has been superseded by its manufacture from the chloride.

lative. The process consists of two stages :

The Greek language has two forms of comparison. The first, 1. The Salt-cake Process.-A charge of five or six cwt. of and by far the most common, adds to the positive - Tepos, -tepa, diameter, and 12 inches deep at the centre. The lid of this lative; the

second adds for the comparative -iw,-iov, or -wv, -ov, phuric acid is introduced. The following reaction occurs when -os, -a, -ov, etc., respectively point out the masculine, the femi

nine, and the neuter gender.

As in Latin and English, the superlative in Greek denotes H,80, + NaCl = HNaso, + HCl.

either the highest degree of a quality, or a very high degree. T'he hydrosodic sulphate remains, and the hydrochloric acid Instead of these ordinary forms the comparative may be passes throngh the other opening to the bottom of a vertical indicated by Maxtov, more, and the superlative

by Madista, most, due, which is packed with pieces of coke, over which water is put before the adjective.

beat is applied :

THE FIRST FORM OF COMPARISON.

«ου,

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name.

N. -τερον. -τατον.

-TaTOS

Let us consider the forms of comparison of adjectives. Ινδος, -ου, δ, Indian. | Νομιζω (νομος), ΙΙ Σπαρτιατικος, -η, -69,

Καλλιας,

και, think, I hold as Spartan. Callias, & proper customary. Τιμιος, , -ον, hon

Ουδεις, -ενος, no one; oured, esteered,
Comparative -Tepos -τερά

Κυκλωψ, -ωπος, και, ουδεν, nothing. valuable.
Superlative
«τατη

Cyclops.

Πατρις, -ιδος, ή, one's Χρησιμοs,
ADJECTIVES IN -ος, -η (-ά), -ον.

| Λακεδαιμονιος, -ου, και, mother country. useful. Most of the adjectives of this class add the forms of com

8 Lacedaemonian, | Σιωπη, -ης, ή, silence, parison to the stem by means of the connecting vowel o or w. The English adverb of comparison than is represented by a The connecting vowel is o when a long syllable precedes; if a (Latin quam); thus, the son is wiser than the father, is in Greek, short syllable precedes, the connecting vowel is w. A short o vios copwrepos EOTIV 7 8 marnp. Another form of comparison syllable is a syllable the vowel of which is short ; a long syllable drops the n, and instead, as in the previous instance, of having is a syllable the vowel of which is long. Diphthongs are long, the same case after the n, than, as before it, puts the second and a vowel followed by two consonants, or one double consonant, noun in the genitive, as d vios oopwrepos Tou Tatpos cotiv. is long. A long vowel or a diphthong is said to be long by nature;

EXERCISE 53.-GREEK-ENGLISH. a vowel made long by standing before two consonants, or one double consonant, is said to be long by position. The rule is 1. Αριστειδης πτωχιστατος ην, αλλα δικαιοτατος. exemplified in these words:

Κυκλωπες βιαιοτατοι ησαν.

3. Καλλιας πλουσιωτατος

Αθηναιων. 4. Ουδεν σιωπης εστι χρησιμώτερον. 5. Σιγη ποτ' Positive. . Comparative. Superlative,

εστιν αιρετώτερα λογου. 6. Ουδεν εστι σοφιας τιμιωτερον. 7. Σοφια κουφ-ος, light ; κουφ-ο-τερος, lighter ; κουφ-ο-τατος, lightest. ισχύρ-os, strong; ισχύρ-ο-τερος, stronger; ισχύρ-ο-τατος, strongest. | απλουστατη. 9. Οι γεραιτεροι ταις των νεων τιμαις αγαλλονται.

πλουτου κτημα τιμιώτερον εστιν. 8. Η Λακεδαιμονιων διαιτα την λεπτ-ος, thin; λεπτ-ο-τερος, thinner; λεπτ-ο-τατος, thinnest.

10. Η πατρις τοις ανθρωποις φιλτατη εστιν. 11. Οι Ινδοι παλεςσοφ-ος, wise; σοφ-ω-τερος, wiser ; σοφ-ω-τατος, wisest.

τατον εθνος νομιζονται. 12. Ω παιδες, εστε ήσυχαιτατοι.

13. εχύρ-os, secure; εχύρ-ω-τερος, securer; εχύρ-ω-τατος, securest.

Οι Σπαρτιατικοι νεανιαι ερρωμενεστεροι ησαν των Αθηναιων. 14. Contracted words in -εος, -ούς, and -00ς, -ούς, undergo con- Πολλοι των χελιδονων εισι λαλιστεροι. 15. Οι δουλοι πολλακις tractions also in the comparative and superlative; the former ψευδιστατοι και κλεπτιστατοι εισιν. blend e and w into w; the latter assume the connecting syllable er, and blend it with the foregoing o; thus

EXERCISE 54.

ENGLISH-GREEK. πορφυρ-eos, purple; πορφυρ-ους.

1. The father is wiser than the son. 2. The mother is more πορφυρ-εω-τερος, πορφυρ-ω-τερος.

talkative than the daughter. 3. Virtue is the most valuable

4. Socrates was the wisest Athenian.
πορφυρ-εω-τατος,
possession.

5. The
πορφυρ-ω-τατος.
απλοος, simple;
απλούς.

Athenians were wiser than the Lacedæmonians. 6. No one of

the ancient Greeks was wiser than Aristides. 7. Men are απλο-εσ-τερος,

απλ-ουσ-τερος.
απλο-εσ-τατος,
απλ-ουσ-τατος.

quieter than boys. 8. The Lacedæmonians were very strong.

9. Swallows are very chattering. 10. The raven is very thievish. Here belong also contracted adjectives of two terminations 11. Socrates' manner of life was very simple. in -ους And -ουν, ας ευ-νοος, ευ-νους (well-disposed), ευ-νοον, ευ-νουν; Comparativo, ευνο-εσ-τερος, ευ-νουσ-τερος ; superlative, ευνο-εσ

ADJECTIVES OF THE THIRD DECLENSION. τατος, ευ-νονσ-τατος.

In adjectives of the third declension, the comparison-forme The ensuing four adjectives in -alos---namely, yepalos, old; are added to the adjective stem, either immediately or by means Talalos, of old, ancient ; nepatos, belonging to the other side (of of the connecting syllable eo or 10. The adjective stem appears the river) ; o xodalos, idle-take the endings -tepos and -ratos, in either the neuter or in the genitive, after the removal of the without any connecting vowel, as

termination -0ς. .
Positive.
Comparative.
Superlative.

The adjectives in -US, -Ela, -v; in -os, -ES ; in-os, -av, as well as

uarap, blessed, affix the comparison-forms immediately to the γεραι-OS. γεραι-τερος. γεραι-τατος.

stem; asNote that pinos, loving, commonly has in the comparative

Positive. Neuter. Comparative. Superlative. μαλλον φιλος, and in the superlativo φιλτατος.

γλυκυς, Sweet,

γλυκυ-τερος, γλυκυτατος. The following adjectives in -os-namely, evoios, fair (weather);

αληθης, true, -€5, αληθεσ-τερος, αληθεσ-τατος. ήσυχος (δ and ή), quiet; ισος, like; παραπλησιος, similar; ορθριος,

πενης, poor,

πενεσ-τερος, early (in the morning); o4los, late; apwlos, in the dawn--append

μελας, black,

μελαν-τερος, μελαν-τατος. the connecting syllable ai to the stem, so that the comparative and superlative exactly correspond to the forms of the preceding, The adjectives nous, sweet, Taxus, swift, and nodus, much, take

μακαρ, blessed,

«αρ. μακαρ-τερος, μακαρ-Τατος. Positive, , Comparative.

ν,

πενεστατος.

•ES,
-αν,

as

Superlative. the second comparison-forms, namely, those in -1ων and -ων. μεσ-ος. μεσ-αι-τερος. μεσ-αι-Τατος.

The adjectives in -wv, -ov (gen. -ovos), assume the connecting Two adjectives in -0s-namely, ερρωμενος, strong, and ακράτος, | syllable εσ; for example, ευδαιμων (nom. -ον), fortunate, happy. unmixed-append the connecting syllable co to the stem, as Positive. Neuter. Comparative.

Superlative. ερρωμεν-εσ-τερος, ερρωμεν-εσ-τατος και ακρατ-εσ-τερος, ακρατ-εσ ευδαιμων, ευδαιμον, ευδαιμον-εσ-τερος, ευδαιμον-εσ-τατος. So αιδοιος, -α, -ον, modest, has in the superlative αιδοι

Adjectives in - & take as their connecting syllable partly ec The following four adjectives in -os-namely, nalos, talka

partly ισ, astive; uovopayos, eating alone; oyopayos, fond of good eating;

αφηλιξ, Genitive, αφηλίκος, growing old. and mtwxos, poor, begging-take co for their connecting syllable,

Comparative, αφηλικ-έστερος. as λαλ-ος, λαλ-ισ-τερος, λαλ-ισ-τατος.

Superlative, αφηλικ-εσ-τατος. Adjectives in -975 (gen. -ov), after dropping the ns, take the

αρπαξ, Genitive, αρπάγ-25, robbing. connecting syllable co, as

Comparative, αρπαγ-ισ-τερος.
Positive.
Comparative.

Superlative, αρπαγ-ισ-τατος.

Superlative. κλεπτ-ης, thiewish.

κλεπτ-ισ-τερος. κλεπτ-ισ-τατος. The adjectives in -ers, -ev, whose stem ends in yt, append the So also one in -ης of the third declension-namely, ψευδης, -ες

terminations - Tepos and -Tatos immediately to the stem; but in (gen. -ος, -ους), false–makes ψευδιστερος, ψευδιστατος.

the coming together of two t's the first changes into o, whereon

the foregoing v is dropped ; the process and the result may be VOCABULARY.

presented thus:-Αγαλλω, I adorn; in| Αίρετος, -ον,| Βιαιος, , -ον, violent. Pos. χαριεις, -ιεν. Gen. χαριεντ-0s, pleasing. the middle voice chosen. Δικαιος, -α, -ον, just.

χαριεντ-τερος. 1 with the dative, I Αριστειδης, -ου, o, Εθνος, -ους,

χαριεν-τερος. am proud of. Aristides.

people, nation,

Com. χαριεσ-τερος. Sup. χαριεσ-τατος.

τατος. . εστασOS.

το,

are

Compounds of xapus interpose w, as

remains, which indicate slow changes of species, but we pass Pos. eriyapis, bo Gen. EriXapıt-os, pleasing.

directly from highly inclined strata to systems resting horizonCoτη. επιχαριτ-ω-τερος. Sup. επιχαριτ-ω-τατος.

tally upon them—from rocks of one mineral composition to VOCABULARY.

those of a totally different character--from an assemblage of

organic remains in one stratum, to find in its neighbour immer Artn, -175, , Ætna. | EvoeBys, -es, pious. 'Opun, ons, i, im- diately above it a world of life well nigh totally distinct, and Ada, suddenly. Ευχαρις, , (gen. pulse,

only possessing a few species in common with it. These facts Arderns, -es, power - Tos), attractive. eagerness, zeal. were understood to indicate that the surface of the earth had less, weak. "HBn, -95, h, youth. Ovõe, nor, not even.

been subject to catastrophes, which overwhelmed the existing Aruxin -as, i, mis- Kpetias, -ov,d, Critias. Tlapepxoual, I pass orders of life. These periods of disorder were succeeded by fortune. Μεσοτης, -ητος, ή, by.

ages of repose, during which the usual order of things con. Αφροδίτη, -ης, the middle, mode- MpeoBus, & (the only tinued, new strata were deposited on the shattered and upheaved Aphrodite(Venus). ration.

1 cases besides the crust, and new species of life arose from the wreck of the overBabus, -ELO, -V, deep. Nonja, ŠTOS, to, a

acc. thrown world. But do the observed facts demand such a theory Bapus, -eta, -v, heavy, thought (some apegbuy, and voc. for their explanation ? Suppose, for example, that Wales

nom.

burdensome. thing in the vous, atpeoBu; in the where the oldest stratified rocks are developed, the SilurianEyrpatns, -es, selfmind).

plural, aperbers), was now submerged, and upon the present land a deposition of controlled, absti- Oplos,-n, ov,straight, old, an old man.

sediment was made, in which specimens of the various animals nent. right. KUS, -Ela, -v, swift.

now living in the Irish Channel were fossilised; and suppose EXERCISE 55.-GREEK-ENGLISH.

that, in process of time, the upheaving force lifted the ocean1. Αιψα, ως νοημα, παρερχεται ηβη, ουδ' ίππων ορμη γιγνεται | bed, and it became again dry land, whose surface was studied ταχυτερα. 2. Το γηρας βαρυτερον εστιν Αιτνης. 3. ο θανατος | by the then existing race of geologists: what would be the facts τα βαθυτατα υπνω παραπλησιωτατος εστιν. 4. Οι νεοι τοις των

which presented themselves ? A series of strata reposing hori. πρεσβυτερων επαινοις χαιρoυσιν. 5. Φιλιας δικαιας κτησις εστιν zontally upon rocks of a distinct mineral character, which were ασφαλεστατη. 6. Η μεσοτης εν πασιν ασφαλεστερα εστιν. 7. highly inclined ; the fossils of the upper rocks being utterly Οι γεροντες ασθενεστεροι εισι των νεων. 8. Bovans op ons ouder distinct from those of the lower. Would they then be warranted εστιν ασφαλεστερον. . 9. Οι κορακες μελαντατοι εισιν. . 10. in coming to the conclusion that when the period of the depoΣωκρατης εγκρατεστατος ην και σωφρονεστατος. 11. Εν ταις

sition of the Silurian had come to an end, a mighty convulsion ατυχιαις πολλακις οι ανθρωποι σωφρονεστεροι εισιν, η εν ταις

upheaved the strata, killed all existing life, and that a new EUTXIALS. 12. Κριτιας ην αρπαγιστατος. . 13. Αφροδιτη ην

creation peopled the seas with new types of life? We see how χαριέστατη πασων θεων. .

erroneous such a speculation would be.

The student must bear in mind a few prominent truths, which EXERCISE 56.-ENGLISH-GREEK.

we shall illustrate, from facts observation has procured. 1. Old age is very burdensome. 2. Nothing is swifter than

1. That no rocks can be formed on dry land. Hence the surthought. 3. Moderation is the safest. 4. No bird is blacker face of the earth may be divided into areas of deposition and than the raven. 5. The boy is swift, the man is swifter, the of non-deposition. horse is swiftest. 6. Youth is more attractive than old age. 2. That in the making of rocks no new matter is used; it is 7. The Ethiopians are very black. 8. No one of the Athenians only a re-arrangement of materials already in existence. was more self-controlled than Socrates. 9. Critias was more 3. That the material deposited in one place represents the given to plunder (robbing) than Alexander. 10. Nothing is degrading action which has taken place in another. more pleasing than beautiful flowers.

4. That at all times there have been continents and seas, for

in every class of rocks we have fossil evidence of the existence LESSONS IN GEOLOGY.-III.

of land; and that the wearing down of the continents has been

the chief source of the sediment deposited upon the oceanGEOLOGICAL AGENTS-RAIN-SPRINGS-WELLS.

bed. HAVING given a general idea in the last chapter of the appear. 5. That the earth's crust has from all time been subject to anice which stratified and unstratified rocks present, we proceed local upheavings and subsidings, which have now caused the to answer the natural question, What causes have contributed to ocean-bed to become dry land, and now the dry land to be subthe composition of these rocks, and by what means have they merged. Thus, with the exception of those localities where been placed in their present positions ?

the primary rocks lie exposed, the whole surface of the earth We shall confine our attention first to the stratified rocks. has alternately served as " an area of deposition," or of “non

These rocks owe their existence to aqueous action. A casual deposition.” And even with regard to the primary rocks which acquaintance with their appearance is sufficient to indicate this ; now form the surface, we cannot declare positively that they but as we proceed we shall find that they contain, in a fossil never were submerged, for they may have been covered with state, innumerable remains of animal and vegetable life; and that sedimentary strata which has subsequently been washed off ; these are so universally the remains of marine and aquatic life, though this may generally be decided by the appearance of the that when the fossil of a land animal or a bird is discovered, it face of the rock. These are the main principles which observais considered a rare exception to the rule. No other proof is tion of existing causes has enunciated. We shall treat of these required beyond this of the fact that stratified rocks were causes in the order of their observation, taking the most imorice sediment, deposited at the bottom of seas and lakes ; in portant agent first. the course of their accumulation, shells, dead fish, occasionally

THE GEOLOGICAL ACTION OF WATER. the wody of a land animal brought down by a river, sea-weeds, corals, etc., became embedded in the sediment, and by processes, Rain.—The atmosphere is capable of holding in solution a to be described in due time, impressions were taken of them in vast quantity of water. When its temperature is raised, this the matter of the deposit then being made, and they are pre- capability of holding moisture is greatly increased ; c. the sented to us as fossils, a word which is derived from the Latin other hand, if by any cause its temperature be decreased, the fossus, " dag up."

moisture it contains first condenses into clouds ; and if the temThis action is now going on, and there is no reason for be- perature fall still lower, the minute globules of which the clouds lieving that it has ever varied, but that existing causes have are composed coalesce into drops, and descend to the earth as rain. been the agents by which all the stratified rocks have been pro The amount of water thus suspended in the firmament above duced.

us is beyond our conception. A thunder shower even has been Geologists have only lately arrived at this conclusion. At known to pour down upon a limited area as much as 200,000 first sight, many facts seem to oppose it. For when the fossi- tons of water in a few hours. liferous strata are arranged in chronological order—that is, The fall of rain varies with localities. In the equatorial when they are piled one above the other in the order in which regions Humboldt calculates that 96 inches fall annually. Here they were deposited--the series does not, as we might expect, the great solar heat causes the distillation of the ocean-waters prezent a gradation of rocks gradually passing from one mineral to be carried on with vigour. At

a latitude of 45°, the

rain-fall character to another, and containing

animal and vegetable is only 29 inches; and 15o further north, 17 inches. In the

British Islands the average is about 36 inches; but even in our | effaced, but a layer of mud is deposited upon them. In process small island the difference of the rain-fall in neighbouring locali- of time this becomes rock, and when split the rain-prints are ties is very remarkable: for instance, at Whitehaven, in Cum-exhibited, faithfully registering the fact of the shower, and berland, there fell, in 1849, 32 inches; while in the Vale of frequently showing the direction of the wind, by the cavity Borrowdale, only 15 miles distant, the fall was 142 inches- formed by the drop being deeper on that side to which the drop almost four times the amount. This is due to the position of was driven. the valley ; it is traversed by the prevailing winds, which come Springs.—Not satisfied with the work done as individuals, the loaded with moisture from the sea. The mountains condense rain-drops seek to combino their power, and collecting in cavithis moisture, and the valley receives the rain.

ties in the hills, and in the more porous rocks, form springs The most remarkable instance of this combination of local which permanently feed rivers. Although the degrading action causes is perhaps found in the case of the Khasia Hills, which of springs cannot be compared to that of rivers, yet it is by no form the southern side of the valley

means despicable; their action is of the Brahmapootsa, just as it

continuous, and every spring wears enters the delta of the Ganges.

for itself a valley, of greater or less These mountains are some 4,000 or

size, according to the length of time 5,000 feet high, and their south

it has flowed, the quantity of water flank looks over the delta towards

it discharges, and the nature of the the Bay of Bengal. When the south

rock from which it issues. monsoon blows, it traverses the

The origin of one class of springs river-flats, and arrives at the foot of

will be at once conceived by watchthe Khasias loaded with moisture.

ing a child dig a hole on the seaImpinging upon the mountains, it is

beach. The retiring tide has left driven upwards; it rises into colder

the sand saturated with water, which regions, and to a height at which

drains into the hole and soon fills it. the air is greatly rarefied. Now,

This is precisely the case with porous when air is rarified, it acquires a

rocks soaked with rain-water. If s greater power of containing heat, and

well be sunk down to the base of such consequently it absorbs its own sen

a rock, where a less porous stratum sible heat, and thus its temperature

underlies it, water will soon rise in falls. From the combination of Fig. 7.-- RAIN-PRINTS AND WORM-TRACKS IN CARBONIFEROCS the excavation. Now suppose there these causes the monsoon delivers

GREEN SLATE.

exist some fissure in the rock, up its moisture, and as much as

we have at once a natural well; 600 inches of rain fall on the south flank of the Khasias yearly. and as soon as an outlet is found, which is at a lower level The denuding effect of this vast quantity of water is greatly than the surface of the water, a spring will be the result. enhanced by the fact that it almost all falls in the six months Springs will be plentiful at the outcrop of a layer of clay, or in which the monsoons blow. In many tropical countries the some other deposii impervious to moisture, above which lies a fall averages 200 inches. Just as there are combinations of local porous rock, such as chalk or sandstone, which will retain the circumstances which produce unusual rain-falls, so there are rain. The reason why there is not an issue of water from the regions where the opposite effect is the result. Rainless regions whole line of the outcrop of the impermeable strata is that the are found generally in the centres of vast continents. Ere the water follows the valleys formed by the inequalities of the surwinds reach these localities they have been dried, the moisture face of the strata, so that where a spring does occur we may they earried having been condensed by mountains which inter- conclude that that is the end of a valley of which the spring vened between the seas and the centre of the continent. There may be conceived to be the river. In this instance the valley is a strip of coast-line in Chili and Peru where no rain falls, for made the river, and not the river the valley. the prevailing winds deposit their moisture on the opposite Artesian wells have thrown some interesting light on the flank of the Andes, and when they reach the countries to the underg ound system of waterworks. These wells or borings ieeward they are dry. No rain has fallen here for years, as may are made by an auger generally about four inches in diameter. be proved by the fact that houses are built of “Chili saltpetre,” When rock is reached, it is triturated by an iron rod, and the or sodium nitrate, which is a salt soluble in water; hence the débris removed by the auger. The sides of the bore are proexistence of the structures is a testimony to the rainless cli- tected by sinking iron pipes. The boring is continued until a mate. Considering that every drop of rain does a geological porous stratum is reached. The Artesian wells in the neighwork—it either carries down a grain of sand to a lower level, or bourhood of London are sunk to reach the chalk, and are about soaks into the soil, loosening it for the action of the next 320 feet deep, and they yield some 15,000,000 gallons a day; shower—it may be conceived what a vast and universal work but the water does not rise so high in the well as it used, is being carried on by drops of rain. If it required proof that proving that the chalk reservoir is not inexhaustible. the surface of the earth had always been subject to the action There is a well at Grenelle, near Paris, 1,800 feet deep. of rain, we should find it in

St. Paul's.

Frequently, in the course of the frequent discovery of rain.

the boring, a subterranean cavity prints in some of the oldest sys

is tapped, from which the water tems. Many specimens of these

rises with great force. At interesting remains have been

Tours, when the depth of 364 found in rocks of the Carbonife- Fig. 8.-IDEAL SECTION OF LONDON BASIN. AA, CHALK; BB, CLAY; feet was reached, there was a rous period. During the age in c, GRAVEL; a, SURFACE WELL; K, ARTESIAN WELL. sudden rise of water, which which the coal-fields were depo

brought up with it a quantity of sited, the atmosphere—to encourage the rapid growth of the sand, shells, branches of thorns, seeds, etc., and there was readense vegetation which characterised that epoch-must have son to believe that these came from some of the valleys of Aubeen highly charged with moisture, and, as a consequence of this, vergne, 150 miles distant, proving a cavernous connection showers of rain must have been of constant occurrence.

between the two places. Fig. 7 shows a slab exhibiting rain-prints and worm-tracks, Fig. 8 represents an ideal section of the London basin : discovered in the carboniferous green slate in Nova Scotia. a is a “surface well;" H, an Artesian well. The water from a

Sir Charles Lyell has most satisfactorily explained the pre- looks sparkling, and is more refreshing than from H; and is delesence of these rain-prints. His observations were made on the terious just in proportion as these qualities recommend it, for shores of the Bay of Fundy, where the tide rises higher than they are due to organic matter and nitrates, which the rain any other place in the world-more than 70 feet. The exten- gathers as it comes into contact with decomposing animal matter sive mud-flats are left dry for the period between the high tides. on the surface; whereas the water from u enters the chalk If a shower fall while the mud is yet soft, an impression is strata, a A, far out in the country. made, which the hot sun bakes into an enduring cast, so that Artegian welis derive their name from Artois, in France, when the next high tide covers the flat the rain-prints are not where they were first sunk.

[graphic]

B

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