8. Σrepavos, -ov, ó, a crown, hence our proper name, Stephen. 9. Aisxvvoμai, I am ashamed of, from aixos, -oûs, hatefulness, shame.

10. Σίδηρος, -ου, δ, iron; οξύνω, I sharpen; in παροξύνει, the preposition wapa strengthens the force of the verb; éraipos, -ov, d, a companion, friend.

11. Auntos (from auaw, I bind in bundles), harvest time; veros (from vew, Lat. pluere, to rain), rain; bepos, -ous, To,

summer.

12. Akavba, -ns, h, a thorn; pvw, I produce (Lat. fui, I was), proual, I am produced, I am born, I spring up; μeOvoμos (from μetv, wine, strong drink), drunken; appwv, -ovos (from a, and par), senseless, fools.

6. Γίνομαι (the old form of γιγνομαι, compare γενos, a race, a kind), I become; Toinтns, -ov, ó, a doer, a maker, hence our poet, the great maker, that is, inventor; aкpoaтns, -ov, d, a hearer. 7. Opnokela, as, ǹ, service, God's service, religion; kalapos, -a, -ov, pure; aμιavтos (μiaivw, I spot), unspotted; kui, even, that is, ούτος, αὕτη, τουτο, this ; επισκέπτομαι (επι, over, and σκεπτομαι, I survey) I go to see, or visit; from the same root is our bishop, that is, an overlooker, a superintendent; oppavos, -ov, 8, our word orphan; xnpa, -as, ǹ, a widow; xiis, -ews, n, affliction; avтwv, of them, their; aonixos, -ov, unstained (øπiλos, a stain), τnpew, I keep, preserve.

13. Evvola, as, n, sense (from ev, in, and vous, the mind); Tuλŋ, -ns, ǹ, a gate; ekkλivw (ek, from, and kλivw, I bend), I turn away.

15. Χαίρω, Ι τejoice; κακοποιος, -ου, 8 (кaкоs, evil, and Telew, I do), an evil-doer; (nλow, I desire, envy; aμаρтwλos (Quaprava), a sinner.

16. Poßeoμai, I fear, reverence.

17. Пapaßaλλw (яара, near, Вaλλw, I throw), I apply to; cos, thy, here the personal pronoun is used for the article, ordinary Greek giving το οὓς; εμος, my.

18. Exenμoovvn (from eλeos, pity), mercy; hence our word eleemosynary, which, through the old English almesse, is contracted into alms.

19. ПрeσВʊтnр (our presbyter, whence our priest), an old man; πολιός, -α, -ον, bald, grey; πολιαι, grey hairs (understand τριχες, hair).

20. Φαινομαι, Ι αppear ; ἑαυτῷ, to himself; κατευθύνω, I direct, guide. 21. AKOλаσTOS, -ov (a, not, and коλafw, I punish, restrict), warestrainable, riotous; ßpiσTIKOS, -ov, insulting; μeon, -ns, n, drunkenness; TOLOVTOS, Such; TOLOVTOIS, such things; σvμTλeкw love, with, and wλeкw, I fold), I bind together; ovμпλeкeтαι, is entangled in, is chained to.

EXERCISES FROM THE NEW TESTAMENT.

από του κόσμου.

1. Μακάριος (understand εστιν) ανηρ ὡς ὑπομενει πειρασμον. 2. Έκαστος πειραζεται ύπο της ίδιας επιθυμίας. 3. Η επιθυμια τίκτει ἁμαρτίαν, ή δε ἁμαρτια αποκυει θανατον. 4. Πασα δοσις αγαθη και παν δώρημα τέλειον ανωθεν εστι καταβαινον απο του Πατρος των φώτων. 5. Οργή ανδρος δικαιοσυνην Θεου ου κατεργάζεται. 6. Γίνεσθε ποιηται λόγου, και μη μόνον ακροαται. 7. Oрnσкelа καθαρα και αμιαντος παρα τῷ Θεῷ και Πατρι αύτη εστιν, επισκεπτεσθαι ορφανους και χηρας εν τη θλίψει αυτών, ασπιλον ἑαυτον τηρειν 8. Η ανωθεν σοφια πρωτον μεν ἁγνη εστιν, επειτα ειρηνική, επιεικής, ευπειθης, μεστη ελεον και καρπων αγαθών, αδιάκριτος, ανυπόκριτος, καρπος δε δικαιοσυνης εν ειρηνη σπείρεται τοις ποιουσιν ειρηνην. 9. Ποθεν πολεμοι και ποθεν μαχαι εν ύμιν ; ουκ εντευθεν, εκ των ἡδονων ὑμων, των στρατευομένων εν τοις μελεσιν ὑμων; 10. Μοιχοι και μοιχαλίδες, ουκ οίδατε ότι ἡ φιλια του κόσμου εχθρα του Θεου εστιν; 11. O eos υπερηφανοις αντιτάσσεται, ταπεινοις δε διδωσι χαριν. 12. Els ἐστιν ὁ νομοθέτης και κριτης, ὁ δυναμενος σώσαι και απολεσαι. The General Epistle of St. James.

VOCABULARY TO THE EXTRACTS FROM THE NEW TESTAMENT. 1. Maxapios, -a, -ov, happy, blessed; iñоμevw (vro, under, and per, I remain), I endure; reipaσμos, -ov, d (πeipasw, I try, tempt), trial.

2. 'ExaσTOS, -n, -ov, each, every; idios, -a, -ov, one's own. 3. ATOKνEW (аTO, from, and Kuw, I conceive, am pregnant), I bear, I bring forth; Bavaros, ou, d, death.

4. Doris, -ews, ǹ, a giving; dwpnua, -aros, TO, a gift; TEXEIOs, a ov, perfect; avwbev (ava), from above, the termination ev gives the idea of from, compare in Sentence 9, Tobey and εντεύθεν; καταβαίνω (κατα, down, and βαινω, I go), I come dinem, eσTI KAT, literally, is coming down, is constantly coming down-a beautiful description of the constancy of the heavenly Father's goodness; pws, pwтos, To, light.

5. Opyn, ns, (the root of opeyouai), desire, effort, a strong

|

9. Ποθεν, whence; εντευθεν, thence; ύμων, of you, your σтρатEvоμal, I war; των στρατ ευομένων, which make war ; μeλos, -ovs, to, a limb, member; bμiv, in you.

10. Μοιχος, -ου, δ, an adulterer; μοιχαλίς, ίδος, ή, an adulteress; ovк oldate, know ye not? ex@pa, -as, ǹ, hatred.

11. Teрηpavos (úñeр, above, high, too much, and paivw, I show), haughty; avтiтaσσoμai (avтı, against, and raσow, I set), I array myself in opposition to; тaжEivos, -n, -ov, low, lowly, humble; didwol, he gives.

12. Νομοθετης (νομος, a law, and τιθημι, I place), a laregiver; Suvapai, I am able; d dvvaμ evos, who is able; σwjw, I save; απολλυμι, I destroy ; σωσαι and απολεσαι are infinitives governed by ὁ δυνάμενος.

KEY TO EXERCISES FROM THE BOOK OF PROVERBS. his mother. 1. A wise son maketh a glad father, but a foolish son is a grief to diligent make rich. 2. Poverty bringeth a man low, but the hands of the 3. The blessing of the Lord is on the head of the just. 4. The memory of the just is preserved with praise, but the name of the impious is extinguished. 5. Hatred begetteth strife. 6. He who applieth the wisdom of his lips striketh the senseless man (as) with a staff. 7. The double-tongued man concealeth his thoughts in the assembly, but the faithful man concealeth only his deeds by speech. 8. A virtuous woman is a crown to her husband. 9. The just man hateth an unjust speech, and even the ungodly man is ashamed of it. 10. As iron sharpeneth iron, so a man sharpeneth the face of his friend. 11. As dew in harvest time, and as rain in summer, so is honour to one who is not indiscreet. 12. Thorns grow up in the hand of a drunkard, and slavery in the hand of the foolish. 13. Wisdom and good sense are in the gates (i.e., dwellings) of the wise, 14. The and the wise turn not away from the mouth of the Lord. fool perishes in his follies. 15. Rejoice not with them that do evil, nor emulate sinners. 16. Fear God, my son, and the king. 17. Turn thine ear to the words of the wise, and hear my word. 18. Mercy and truth are a king's defence. 19. Wisdom is an ornament to young men, and houry hairs are the glory of old men. 20. Every man appears to himself just, but the Lord directeth the heart. 21. Wine is a thing that is ungovernable; drunkenness is that which begetteth insolence, and every foolish person is entangled in such things.

KEY TO EXERCISES FROM THE NEW TESTAMENT. 1. Blessed is the man who endureth temptation. 2. Each man is tempted by his own lust. 3. Lust produceth sin, and sin bringeth forth death. 4. Every good gift and every perfect gift cometh down from above, the Father of lights. 5. The anger of man worketh not the righteousness of God. 6. Become doers of the word, and not hearers only. 7. Pure and undefiled religion before God and the Father is this, to visit the orphans and widows in their affliction, and to keep

himself unspotted from the world. 8. The wisdom that is from above is first pure, then peaceful, just, easily persuaded, full of pity and good fruits, without partiality, without hypocrisy, and the fruit of righteousness is sown in peace in those that pursue peace. 9. Whence are wars and whence are fightings among you, are they not thence even from your pleasures, which war in your limbs ? 10. Ye adulterers and adulteresses, know ye not that the friendship of the world is enmity against God? 11. God sets himself against the proud, and giveth grace to the lowly. 12. There is one lawgiver and judge, who is able

to save and destroy.

Compare the above with the translation of the Bible now in use.

HODES OF

HYDROSTATICS.-IV.

DETERMINING SPECIFIC GRAVITY (continued) — HYDROMETERS-TABLE OF SPECIFIC GRAVITIES.

IN our last lesson we examined the mode of ascertaining the specific gravity of a liquid, we must now see what is the mode of procedure in the case of solids. Happily we are not limited to one method, there being several from which we can choose that which seems the most convenient for the special case in hand. We will begin with the simplest. Suppose we have a powder, or some small fragments of a solid substance insoluble in water, we should use the small flask shown at Fig. 13 in the

last lesson.

Fill the flask with water, taking care to avoid bubbles, insert the stopper, and, by a piece of rag or blotting-paper, adjust the level of the liquid to the mark on the neck; then carefully wipe off all moisture adhering to the sides. Having put the flask into one scale, put the counterpoise into the other, and add weights till they balance; you will thus obtain the weight of water which the flask holds. If the amount is already known, this weighing may be dispensed with. Next, carefully weigh the substance whose specific gravity you want to ascertain. The stopper must now be removed from the flask, and the powder or small fragments dropped in. They will, of course, displace some of the water, which will flow over. The stopper must then be carefully replaced, the superfluous liquid wiped away, and the flask again weighed. The difference between this weight and the weight of the solid and water together will show how much water is displaced-that is, the weight of a quantity of water equal in bulk to the solid. Divide the weight of the solid by this and we shall have the specific gravity required. Here is an example which will explain it better than a mere description can do.

Grains.

have then merely to divide the weight in B by that in A. The result is exactly the same whichever way we adopt. The following, then, is the general rule:-Divide the weight in air by the loss of weight in water, the quotient will be the specific gravity of the substance.

Thus, a stone weighed in air Immersed in water it weighed

Loss of weight in water

Grains.

286

174

112

Its specific gravity, therefore, is = 2.553. We can, on this principle, ascertain the specific gravity of a liquid by weighing a substance in it, and then in water. Since it displaces an equal bulk of each, the loss of weight in the liquid divided by the loss in water will give the required specific gravity.

The two plans we have mentioned are used when the substance is insoluble in water. Many crystals and chemical substances, whose specific gravity it is important to know, are, however, soluble, and therefore some other means must be We have first to find some liquid in which the substance is insoluble. Oil of turpentine will frequently be found to answer, or, for many substances, alcohol may be used.

resorted to.

Having chosen the liquid, we proceed, as before, to find the weight of a volume of it equal in bulk to the substance, either by weighing the solid in it and ascertaining the loss of weight, or by means of the flask. We then ascertain the specific gra vity of the liquid, and from this, by the following equation, we can ascertain the weight of a bulk of water equal to the solid. As the specific gravity of the liquid is to that of water (which is 1) so the weight of the equal bulk of liquid is to that of the

same bulk of water.

We will illustrate this by an example recently set at an examination.

A piece of blue vitriol weighs 3 ounces in vacuo and 1.86 in oil of turpentine. What is its specific gravity, that of the turpentine being 0.88 ?

Since it weighs in vacuo
And in oil of turpentine only

Ounces.

3.0

1.86

1-14

12.4

Brass being a compound metal, composed of copper and zinc, its specific gravity varies slightly according to the proportion in which they are mixed, the drawing of it into wire also makes a difference, as the particles are forced different distances apart. In ascertaining specific gravities, great care has to be taken to avoid air-bubbles. Some substances are full of pores, into which the air penetrates, and bubbles cling to the surface of others, and materially interfere with the accuracy of the results. When great exactness is required, the substance is dipped into the water when boiling, and thus the air is expelled. It is then set by to cool down to 60°, and weighed as before. Another mode of ascertaining the specific gravity of any body is based on the principle of Archimedes, that a body immersed in liquid loses a portion of its weight equal to that of an equal bulk of the liquid. It is very simple, but requires care; a special arrangement of the scales is also a great advantage.

Fig. 14.

B

The body is first weighed in the ordinary way, a fine hair or thread having been fastened round it. It is then by this hair suspended from a hook underneath the scale-pan, and allowed to dip into a vessel of water, and the weight again ascertained. The difference between the two is the weight it loses in water —that is, the weight of an equal bulk of water, and if we divide its weight in air by this, we obtain the specific gravity. Sometimes the weights are left unaltered in B, and others added to A after the solid is immersed, till the scales again balance; we

This, then, is what an equal bulk of turpentine weighs. Now the specific gravity of the turpentine is 0.88; or, in other words, if any bulk of it weighs 88 ounces, an equal bulk of water will weigh 100 ounces. How much, then, will water, equal in volume to 114 ounces, weigh? The following equation tells us :

As 88 1.14: 100: 1.295.

This, therefore, is the weight of a volume of water equal in bulk to the vitriol, and hence the specific gravity is 2.316. 1-293 You will have noticed in the above example, that the weight of the blue vitriol is stated to be 3 ounces in vacuo. All bodies ought strictly to be weighed in the absence of the air, as otherwise we do not ascertain their true weight, but that amount less the weight of the air they displace. In practice, however, the difference is so slight, that it is disregarded, and a body is always weighed in air, and this taken as its true weight. A proof, however, that it does make a difference is seen in the fact that if we fill a small balloon with gas, and add weights, so that it can only just ascend, it will apparently have no weight at all. The real fact being, as we shall see when we come to treat of Pneumatics, that its weight is then just equal to that of the air it displaces.

There is still one class of substances whose specific gravity we cannot ascertain by any of the ways hitherto described; it is those which are lighter than water. These, when immersed in water, seem to lose more than all their weight, for they have a tendency to rise. We have, therefore, to proceed in a different way. A piece of metal is procured heavy enough to cause the substance, which we will suppose to be a piece of wood, to sink when attached to it. This sinker is weighed in air and then in water, so as to ascer tain the weight of water it displaces. It is then fastened to the wood, and the two together weighed in air and in water; we thus ascertain the weight of water they together displace. From this we deduct the amount which is displaced by the metal, and thus find out the amount displaced by the wood

Grains.

The piece of cork in this case was porous and contained air, and therefore its gravity appears much less than that of cork really is, it being usually set down in the table as 240. A rough estimate of the specific gravity of such a substance may be formed by observing to how great a depth it sinks in water. If three-fourths of it is immersed, its specific gravity is 0.75.

930

In the manufactures it is frequently required to Fig. 15. know the strength of some solution, and this may be found by ascertaining its specific gravity. The strength of spirit is thus taken by the excise; milk is also sometimes tested this way to find whether or not it is adulterated. In such cases no very great degree of accuracy is required; the process, however, must be simple, so that it may be carried out by a man without much special knowledge. Several pieces of apparatus have accordingly been devised, which are known by different names according to the special purposes for which they are intended. Hollow glass beads are prepared, and weighted so as to have different specific gravities, which are plainly marked upon them. If we take a series of these, and drop them successively into the liquid to be examined, we shall find that some will sink, but we shall come at last to one that just floats on the surface, and this shows the density. For instance, if that marked 930 sinks, and 920 floats, we know that the specific gravity of the liquid is between these two.

More usually, however, an instrument, called an hydrometer, is employed. It consists of a hollow bulb of glass, A, carrying above it a thin tube, with a scale marked on it, or on a paper enclosed in it. A smaller bulb is also blown beneath A, into which mercury or shot are put, so as to adjust the weight, and at the same time cause the instrument to float in a vertical position. The liquid to be examined is poured into a tall glass jar, D, and the hydrometer immersed; the specific gravity may then be read off from the stem.

Fig. 16. It is manifest that the denser the liquid, the higher the instrument will float in it, the weight of the liquid displaced being always equal to that of the hydrometer. If we want great delicacy, the bulb must be made large and the tube small; sometimes the latter is removed and replaced by a graduated wire, and thus great accuracy is obtained; but the greater the accuracy, the less the range. These instruments are usually supplied in sets. Sometimes two are used, one for liquids lighter than water, the other for those heavier; but it is better to have more, each one having a range of about 200; say, for instance, one from 600 to 800, another from 800 to 1.000, and so on. This instrument, when manufactured for testing milk, is called a lactometer-when for ascertaining the strength of spirit, an alcoholmeter, and by other names when made for other purposes. The only difference, however, is in the graduation and the

The instrument is first carefully weighed in air; this weight being constant, should be marked on it. The weight which must be placed on C D to sink the instrument to the mark o should also be carefully noted. To ascertain the specific gravity of a solid by it, the substance is first laid on the upper tray, and weights added till the instrument sinks to the mark 0. The difference between this and the former weight will give that of the solid in air. Now remove the solid from CD, and place it in the lower pan, E F. Some water will be displaced, and the instrument will rise. We accordingly add more weights till it again rests with o at the surface. The weights added are equal to that of the water displaced, and if we divide the weight of the substance by this we ascertain its specific gravity.

Fig. 17.

Thus 450 grains had to be placed on C D to sink the instrument to the mark; when, however, a piece of granite was laid on the scale, 237 grains only were required. The granite, therefore, weighed 213 grains. On being transferred to the lower tray, 79 grains had to be added to CD. The specific gravity of the granite was therefore 213, or 2-696. When we want to use the instrument to find the specific gravity of a liquid, we merely observe what weight is required To this we to sink it in the liquid to the mark on the stem. add the weight of the instrument, and thus find the weight of liquid equal to it in bulk. But we know the weight of an equal bulk of water, for we found before the weight required to sink the instrument to the same depth in water; we have, therefore, to divide the weight of the liquid by that of the equal bulk of water, and the quotient is its specific gravity.

For instance, an hydrometer weighed 600 grains, and, as above, 450 grains had to be added to sink it in water to the mark. When dipped into the liquid to be tested, 310 grains only were required: what was its specific gravity?

1050

The weight of water equal in bulk to the hydrometer is 600+ 450 or 1050 grains, that of an equal bulk of the liquid, 600+310, or 910. The specific gravity, therefore, is or 0.866. Now, though it is found that water answers well as a standard for the comparison of the specific gravities of solids and liquids, gases are so very much lighter than it, that it is much more convenient to take some other substance as a standard to compare them with. A cubic foot of air at a temperature of 60°, and when the barometer stands at 30, weighs about 536 grains, or nearly 1 ounces, while a cubic foot of water weighs 1,000 ounces; the specific gravity of air, taking water as the standard. would, therefore, be 0.00122, and that of hydrogen gas less than of this. Such numbers would be very difficult to remember, and awkward to work with; air, therefore, is fixed on as the standard for the specific gravity of all gases and vapours. The temperature and pressure, however, very greatly alter the bulk of any gas. It is, therefore, necessary to fix on some given temperature for the standard. Now, as in the case of water, 60° is found to be a very convenient temperature, the pressure indicated by the barometer standing at 30 is also fixed on.

It is not, however, always convenient to bring the gas to this temperature; we therefore ascertain the bulk at any temperature. and from that calculate what its bulk would be at 60°. It is found that a gas expands about of its volume at 0° Fahrenheit for each degree it rises in temperature; that is, 460 cubic inches at 0° will measure 470 at 10°, 520° at 60°, and so on. Now the weight of 100 cubic inches of air at 60° is 31-0117 grains, or that of a cubic foot, 536 grains. If, then, we know the weight of any bulk of gas, and the temperature at which it is weighed, we can tell its specific gravity. Thus 80 cubic inches of a gas at a temperature of 40° weigh 35 grains: what We first find what volume the 80 cubic is its specific gravity? inches will occupy at 60°. By the rule just given the volume at 40° is to that at 60° as 500 is to 520.

As 500 520 :: 80: 83.2.