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Present, κωλύομαι, impf, ε-κωλύ-ομην,

ύ.

Future, κωλύ-σομαι, aor. ε-κωλύσαμην, -ῦ.

Οτε οἱ βάρβαροι, etc. Assistance may sometimes be ob. tained towards understanding and construing a sentence by

Perfect, κε-κωλύομαι, perf. fut. κε-κωλύ-σομαι, plpf. e-re- simplifying the arrangement, that is, by bringing the arrange

κωλύμην, ύ.

Passive,

Aorist, εκωλύ θην, fut. κωλύθησομαι, πῦ.

Contrary to the rule, several pure verbs retain the short characteristic vowel either in all the tenses or in some of them. These verbs take a σ in the Perfect and Pluperfect middle or passive, as well as in the first Aorist and Future passive, also in their verbal adjectives: this fact is indicated thus, pass. with ☛; accordingly,

χρίω, I sting, f. χρίσω, a. εχρίσα, inf. χρίσαι; pass. with σ; but,

χρίω, I rub, anoint, f. χρίσω, a. εχρίσα, inf. χρίσαι, a. m. εχρίσαμην; p. m. or p. κεχρίσμαι, inf. κεχρῖσθαι; a. 1. εχρίσθην, v. a. χριστος.

ανύω, I complete, f. ανύσω, a, ηνύσα, inf. ανύσαι, pass, with σ. αρύω, I drano, f. αρύσω, a. ηρύσα, ηρύσαμην, pass. with σ. μυω, I close (e. g. the eyes), f. μύσω, a. εμύσα, p. μεμύκα, I am closed, I am silent.

πτύω, I spit, f. πτύσω, a. επτύσα, pass. with σ.

The following dissyllable verbs in ἒω lengthen the characteristic vowel in the Future active and middle, the third Future, and the Aorist active and middle; and δνω also in the Perfect and Piuperfect active; but in the Perfect and Pluperfect active (except δυω) and middle (or passive), and in the Aorist and Future passive, resume the short vowel : thus,

Aor.

εδύσα εθύσα ελύσα

Fut. Perf. Aor. pass. dvw, I enter, δύσω δεδυκα, δεδῦμαι εύθην θυω, I sacrifice, θύσω τεθύκα, τεθύμαι ετύθην λύσω λύω, I loose, λελύκα, λελυμαι ελύθην The pure verbs which retain the short characteristic vowel in the tenses, interpose & before the tense-endings θην, μαι, etc. in the first Aorist and first Future passive, and in the Perfect and Pluperfect middle or passive, as well as in the verbal adjective. This peculiarity is observed by several other verbs, which either have a long vowel in the root, or lengthen in the tenses a short vowel in the root ; as, ακούω, I hear, εναύω, I set on fire, θραύω, I break in pieces, κρούω, I dash, ψανω, I touch, σειω, I shake, κελεύω, I command, λευω, I stone, κλείω, I shut, πταίω, I knock against, χριω, I smear.

Πάνω 1 cause to cease, has the Perfect middle or passive πεπαυμαι, but Aorist passive επαυσθην.

Κελεύω, I order, command-Perfect Middle or Passive,
Indicative.

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Imperative.

κεκελευου

κεκελευ-σθω

κεκελευ-σθον σε κελευσθων

κεκελευσθε

κε κελευ-σθωσαν

Plural. ε-κε-κελευ σ-μεθα ε-κε-κελευσθε

ε- κε-κελευ-σ-μενοι

ησαν

Fut. pass. κελευ-σ-θησομαι.

VOCABULARY.

Καταπαύω, I terminate, bring
to an end.
Αισθανομαι, (with gen. or acc.)
I am aware of, I perceive.
Σεισμός, ου, ό, an earthquake,

|

Δρομος, ου, o, a running.
Ασπις, ίδος, ή, a shield.
Δυναμις, εως, ή, power.
Δείνως, greatly, exceedingly,
fearfully.

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The soldiers have been commanded to go against the enemy. Our city has been broken by an earthquake. That city will be broken by an earthquake. The city is shaken (Present) by an earthquake. The power of the Persians was broken by the Greeks. The enemy (plural) has been shut up in the citadel. The shields were struck against the spears by the enemy. The war has been made to cease (terminated). The war will have been terminated. May we complete all things well! (opt. dor.) To command (dor.) is easier than to come plete (dor.). The treaty will be broken by the enemy: thou hast been commanded, he had been commanded; I have enclosed; they have enclosed; thou hast sacrificed; I shall finish; to sting; to anoint, the bull has been sacrifced; they will have been commanded.

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LESSONS IN READING AND ELOCUTION.
No. VIII.

ANALYSIS OF THE VOICE.

III.-DISTINCT ARTICULATION,

"CORRECT articulation is the most important exercise of the voice and of the organs of speech. A reader or speaker, possessed of only a moderate voice, if he articulate correctly, will be better understood, and heard with greater pleasure, than one who vociferates. The voice of the latter may, indeed, extend to a considerable distance; but the sound is dissipated in confusion of the former voice not the smallest vibration is wasted-every sound is perceived at the utmost distance to which it reaches; and hence it even penetrates farther than one which is loud, but badly articulated.

In just articulation, the words are not hurried over, nor precipitated syllable over syllable; nor, as it were, melted together into a mass of confusion; they are neither abridged nor prolonged; nor swallowed, nor forced, and, if I may so express myself, shot from the mouth; they are not trailed nor drawled, nor let slip out carelessly, so as to drop unfinished. They are delivered out from the lips, as beautiful coins newly issued from the mint, deeply and accurately impressed, perfectly finished, neatly struck by the proper organs, distinct, sharp, in due succession, and of due weight."*

This department of correct reading belongs, properly, to the stage of elementary lessons. But negligence in general habit, and remissness in early practice, are extensively the causes of an imperfect articulation.

A page or a paragraph of every reading lesson should, previous to the regular exercise, be read backward, for the purpose of arresting the attention, and securing every sound in every word.

always receive its due share of seasonable attention, many
errors in pronunciation are apt to occur in the exercise of
reading, as performed by even the advanced classes in schools.
To avoid such errors, it will be found useful to discuss, closely
and minutely, the correct pronunciation of every word which
in any lesson is liable to be mispronounced. The standard
of reference ought to be Walker's Dictionary, or the same
work improved by Smart.

V.-TRUE TIME.

By true time in elocution is meant an utterance well-proportioned in sound and pause, and neither too fast nor too slow. We should never read so fast as to render our reading indistinct, nor so slow as to impair the vivacity, or prevent the full effect, of what is read.

"Everything tender or solemn, plaintive or grave, should be read with great moderation. Everything humorous or sprightly, everything witty or amusing, should be read in a brisk and lively manner. Narration should be generally equible and flowing; vehemence, firm and accelerated; anger and joy rapid; whereas dignity, authority, sublimity, reverence, and awe, should, along with deeper tone, assume a slower movement. The movement should, in every instance, be adapted to the sense, and free from all hurry on the one hand, or drawling on the other." The pausing, too, should be carefully proportioned to the movement or rate of the voice; and no change of movement from slow to fast, or the reverse, should take place in any clause, unless a change of emotion is implied in the language of the piece.

Exercises on Time.

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The 'slowest' and the quickest rates of utterance have The design of the present Lesson does not admit of detail been exemplified under the head of ' versatility' of voice, and in the department of elocution now under consideration. The need not be repeated here. They occur in the extremes of importance, however, of a perfectly distinct enunciation can grave and gay emotion. never be impressed too deeply on the mind of the student. An There are three important applications of 'time' in conexact articulation is more conducive than any degree of loud-nexion with 'rate,' or 'movement,' which frequently occur ness, to facility of hearing and understanding. Young readers in the common forms of reading and speaking. These are the should be accustomed to pronounce every word, every syllable, 'slow,' the 'moderate,' and the 'lively. The first of these, and every letter, with accuracy, although without laboured the 'slow,' is exhibited in the tones of awe, reverence, and solemeffort. The faults of skipping, slighting, mumbling, swallow-nity, when these emotions are not so deep as to require the ing, or drawling the sounds of vowels or of consonants, are slowest movement of all: the second, the moderate, belongs not only offensive to the ear, but subversive of meaning, as to grave and serious expression, when not so deep as to require may be perceived in the practice of several of the following the 'slow' movement; it belongs, also, to all unempassioned examples. communication, addressed to the understanding more than to the feelings; and it is exemplified in the utterance of moderate, subdued, and chastened emotion: the third rate, the 'lively,' is 2. "He can debate on either side of the question: he can perhaps sufficiently indicated by its designation, as characterdebate on neither side of the question.'

1. "That lasts till night: that last still night."

"

3. "The steadfast stranger in the forests strayed."

ising all animated, cheerful, and gay expression.

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All the exercises on time,' should be repeated till they can 4. "Who ever imagined such an ocean to exist?-Who ever be exemplified perfectly and at once. Previous to practising imagined such a notion to exist ?"

5. "His cry moved me: his crime moved me."

6. "He could pay nobody; he could pain nobody."
7. "Up the high hill he heaves a huge round stone."
8. "Tho' oft the ear the open vowels tire."

9. "Heaven's first star alike ye see."

} IV.-CORRECT PRONUNCIATION.

That pronunciation is correct which is sanctioned by good usage, or custom. Good usage implies the habit of persons of good education, as regulated by the decisions of learning and taste, exemplified in standard dictionaries,-a style which is equally free from the errors of uneducated or negligent custom, and the caprices of pedantry, which falls in with the current of cultivated mind, and does not deviate into peculiarities, on the mere authority of individuals. Good taste in pronunciation, while it allows perfect freedom of choice, as to the mode of pronouncing words liable to variation in sound or accent, requires a compliance with every fixed point of sanctioned usage.

The subject of pronunciation, like the preceding one,articulation, belongs properly to the department of elementary instruction. But as this branch of elocution does not

Austin's "Chironomia," pp. 37, 38.

the following exercises, the student will be aided in forming
distinct and well-defined ideas of time,' by turning back to
the example under 'versatility,' marked as 'very slow,' and
repeating it, with close attention to its extreme slowness. He
will observe that, in the repeating of this example, the effect
of time,' or proportion of movement, is to cause a remarkable
lengthening out of the sound of every accented vowel; an
extreme slowness in the succession of the sounds of all letters,
syllables and words: and along with all this, an unusual
length in all the pauses. It is this adjustment of single and
successive sounds and their intermissions, which properly
constitutes the office of 'time' in elocution: although the
term is often indefinitely used rather as synonymous with the
word 'movement,' as applied in music.

The 'slow' movement differs from the 'slowest,' in not
possessing the same extreme prolongation of sound in single
vowels, or the same length of pause. The slow succession of
sounds is, however, a common characteristic in both.

Example of Slow' Movement.
"THOU, who did'st put to flight
Primeval silence, when the morning stars
Exulting shouted o'er the rising ball;

O Thou, whose word from solid darkness struck
That spark, the sun, strike wisdom from my soul !"

A

'Moderate.'

"There is something nobly simple and pure in a taste for the cultivation of forest trees. It argues, I think, a sweet and generous nature, to have a strong relish for the beauties of vegetation, and a friendship for the hardy and glorious sons of the forest. There is a grandeur of thought connected with this part of rural economy. It is worthy of liberal, and freeborn, and aspiring men. He who plants an oak looks forward to future ages, and plants for posterity. Nothing can be less selfish than this. He cannot expect to sit in its shade, and enjoy its shelter; but he exults in the idea that the acorn which he has buried in the earth shall grow up into a lofty pile, and shall keep on flourishing, and increasing, and benefiting mankind, long after he shall have ceased to tread his paternal fields.”

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ANSWERS TO CORRESPONDENTS.

N. 8. (Norwich); 1, Can't tell; 2, Yes; 3. Webster's Johnson; 4, Can't tell.-Socius (Liverpool): Mizraim is the Hebrew word for Egyptian.J. P. (Edinburgh): No.-A. JOHNSTON (Elton): Lyell's Elements of Geology is the best book for beginners.-T. L. DOUGLAS (Glasgow): As soon as possible.-W. H. E. (Mutual Improvement Society, Plymouth): Womanly is applied to a female, and means like a woman; womanish is applied to a male, and means like a woman in a bad sense, that is, as weak and silly as some women are; effeminate is applied to a male, and means possessing soft and delicate habits and dispositions like some women do, and something even lower than this. As to the cause of earthquakes, read the Lessons ou Geology in the P. E.

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ON PHYSICS, OR NATURAL PHILOSOPHY.

No. XXXII.

(Continued from page 68.)

CALORIC.

ABSORPTION OF CALORIC,

Absorbing Power.-The absorbing power of bodies is that property by which a greater or less quantity of radiant heat is permitted to penetrate their mass. This absorbing power is always in the inverse ratio of their reflecting power; that is, the more that a body reflects radiant caloric the less it absorbs it, and conversely. But the absorbing and reflecting powers are not complementary to each other; that is, the sum of the quantities of the heat reflected and of the heat absorbed do not represent the whole of the radiant heat which falls upon a body. It is always less than this; which shows that the incident heat is really divided into three parts: 1st, that which is absorbed; 2nd, that which is regularly reflected, according to the laws already demonstrated; 3rd, that which is irregularly reflected that is, in all directions, and which is called diffused heat.

Here it will be observed that the order of the bodies in this table is the reverse of that in the table of reflecting powers. MM. De la Provostaye and Desains, who have recently made researches relating to the emissive powers of bodies, have obtained numbers very considerably different from the preceding.

Identity of Absorbing and Emissive Powers.-The absorbing powers of bodies cannot be deduced from their reflecting powers, because, as we have seen, they are not exactly combe determined if we could prove that they are equal, in each plementary to each other. But the absorbing powers would body, to the emissive powers. MM. Dulong and Petit have inferred this from the following experiment. In a large glass vessel, which was kept at the freezing point by immersion in ice, and which was blackened in the interior, they fixed a thermometer heated at first to a certain temperature-say 150 Centigrade; then, having made a vacuum in the vessel by means of a tube in it, which formed a communication between it and an air-pump, they allowed the thermometer to cool by degrees, and they marked the time which it took to fall from 100 to 5. Repeating the experiment in an inverted order, that is, keeping the sides of the glass vessel at 150 Centigrade, and cooling the thermometer to the freezing point, they observed the time which the thermometer took to rise from 5° 1 the same as that which it took to fall from 10° to 5° Centi10° Centigrade; and they found that this time was exactly grade; therefore, they concluded from this, that in the same and that of the surrounding medium, the emissive power is body, and for the same difference between its temperature equal to the absorbing power, since the quantity of heat emitted and absorbed in the same time is equal.

In order to determine the absorbing power of bodies, Leslie employed the apparatus already described in the investigation of their reflecting power (see fig. 169, p. 68): but he removed the plate A and placed the bulb of the thermoscope in the real focus of the mirror. This bulb being successively covered with lamp-black, varnish, gold-leaf, silver-leaf, copper-leaf, etc., the thermoscope under the influence of the source of heat M, indicated a temperature which was higher in proportion as the substance which covered the bulb in the focus absorbed a greater quantity of caloric. In this manner, Leslie proved that the absorbing power of a body increased as its reflecting power diminished. Yet, in these experiments, the ratio of the absorbing powers of different bodies cannot be inferred from that of the temperatures indicated by the thermoscope; for here Newton's law is not strictly applicable, this law being only true in the case of bodies whose substance does not change; whilst that which covers the bulb in the focus varies at every observation. The ratios of the absorbing powers are, however, deducible from that of the emissive powers. It was formerly supposed that the reflecting power gene Emissive Power. The emissive power of a body is the pro-rally increased with the degree of polish in the surface, and perty by which it emits, at the same temperature and from that the other powers, on the contrary, diminished.' But the same amount of surface, a greater or less quantity of heat. M. Melloni has proved, that if a polished metallic plate be The same apparatus, represented in fig. 168, p. 68, was still roughened by scratching lines across its surface, sometimes its employed by Leslie in determining the emissive power of reflecting power is diminished and sometimes it is increased, a bodies. For this purpose, however, the bulb of the thermo- phenomenon which he explains by the greater or less density scope was also placed in the focus of the mirror, and the faces of the reflecting metallic plate. If the plate has first been of the cube M were formed of different metals, or covered with hardened, its homogeneity has been destroyed by the process different substances, as lamp-black, paper, water, etc. The of hardening; its particles are closer together at the surface cube being filled with boiling water, and all the other condi- than in the interior of the mass, and the reflecting power is tions remaining the same, Leslie successively turned each face increased. But when lines are scratched across its surface, of the cube towards the reflector, and marked the tempera- the interior, which is less dense, is exposed to view, and the tures indicated by the thermoscope. Now, in the experiment where the face of the cube was covered with lamp-black, the temperature in the focus of the mirror rose higher than in all the other experiments; and the metallic faces produced the lowest temperatures. By applying the law of Newton, and representing the heat emitted by lamp-black at 100, Leslie derived from his experiments the following table of the emissive powers of bodies:

being equal, every cause which modifies the one necessarily Modifying Causes. The emissive and absorbing powers modines the other in a similar manner. As to the reflecting power, since it acts inversely to the other two, every cause which increases them diminishes it, and conversely. We have seen that these different powers vary in different substances; that the metals have the greatest reflecting power, and lamp-black the least. But that in the same body these powers are also modified by the degree of polish, by the denof the incident rays, and lastly by the nature of the source of sity, by the thickness of the radiant substance, by the obliquity heat.

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reflecting power is diminished. On the contrary, if the plate has not been hardened, and is homogeneous throughout, the reflecting power is increased by the process of drawing lines across its surface with a sharp instrument; and this arises from an increase of density at the surface occasioned by the pressure of the tool employed in drawing the lines.

The thickness of the radiant substances may also modify their emissive power, as proved by the experiments of Leslie, Rumford, and Melloni. The latter philosopher found that by varnishing the faces of a metallic cube filled with water at a constant temperature, the emissive power increased with the number of the coats of varnish, until it reached sixteen coats, and that beyond this number this power remained the same, whatever was the number of additional coats. He found by calculation that the thickness of the sixteen coats was about the one 6350 th part of an inch. As to the metals, gold-leaf varying in thickness from the two hundred thousandth part of an inch to the fifty thousandth part of an inch, having been successively applied to the faces of the cube, the diminution of the radiant caloric was the same. Whence it appears that in the metals the thickness of the coat has no influence on its radiating power.

M. Melloni has also found that the absorbing power varies with the nature of the source of heat. For example, for the same quantity of incident heat, the carbonate of lead absorbs nearly twice as much of it, when it is emitted from a cube full of boiling water, as when it is emitted from a lamp. Lampblack is the only substance which always absorbs the same quantity of heat whatever may be the nature of its source.

The absorbing power varies with the inclination of the incident rays. It is at its maximum at the normal incidence, and it diminishes in proportion as the incident rays depart from the normal position. This is one of the reasons why the sun heats more in summer than in winter; for in summer the solar rays fall less obliquely on the earth's surface.

Applications of Radiant Heat-The properties of the different powers of radiant heat, reflecting, absorbing, and emissive, have numerous applications in domestic economy and the arts. For instance, in selecting raiment for winter or for summer, preference should be given to that which is white; because the emissive power of white garments is less than that of black; consequently they are more opposed, during winter, to the loss of the heat of the human body. Again, in summer, in consequence of their weak absorbing power, they absorb less of the heat of the atmosphere than those that are black; and it is for this reason that they appear to be more cool. For the same reasons, Nature has given to the animals which inhabit the polar regions a covering of white hair, especially during the winter.

In vessels employed for heating liquids, such as coffee-pots, it is more advantageous for this purpose that their surface should be black and unpolished, because then their absorbing power is the greatest. The shining appearance which we are accustomed to give them is obtained at the expense of fuel. If, on the contrary, we wish to preserve a liquid warm as long as possible, we must put it in a metal vessel which is polished and clear, because the emissive power is then least, and the Cooling more slow,

In the Alps, the mountaincers accelerate the melting of the snow by covering it with earth, which increases the absorbing power." In our houses, the exterior coatings of stoves and of heating apparatus should be black, in order to give free emission to the caloric; on the contrary, the interior of our chimreys should be lined with porcelain plates or Dutch ware, white and glazed, in order to increase the reflecting power of the fire, and heat the rooms more effectively.

TRANSMISSION OF RADIANT CALORIC. Diathermens Poster.-There are some bodies which allow radiant heat to pass through them, just as diag kamous bedies admit of the passage of light through them; other bodies have not this property, or possess it only in a slight degree. M. Mellon has given to the former the name of deathers Novice, and to the latter the name of athermous bodies. The pases are the most diathermous bodies; the metals are entirely thermous. Notwithstanding the analogy which exists be tween radiant calore and light, it should be observed in relation to cur subsequent inquiries, that transparent bodies are not always the wost diathermous, and that opaque bodies are by no means always athermous.

1st. The nature of the substance of which the screens (the diathermous bodies) are formed, through which the caloric passes. 2nd. The degree of polish given to these screens. 3rd. The thickness of the screens.

4th. The number of the screens through which the caloric passes.

5th. The nature of the screens already passed.
6th. The nature of the source of heat.

Effect of the Nature of the Screens.-By making experiments on different liquids placed successively in a glass trough, whose opposite faces were parallel and distant from each other about four-clevenths of an inch, and by comparing the indications given by the apparatus, when the liquids were placed in the trough, with the effect observed when the caloric acted directly, M. Melloni found that from 100 incident rays pro ceeding from an Argand lamp as the source of heat, the following were allowed to pass through the different substances mentioned in the table :

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By making experiments in the same manner on different solid substances cut into lamina, or thin plates, whose thickness was about one-tenth of an inch, M. Melloni found the results given in the following table, 100 incident rays of heat being allowed to fall on each:

Substances.
Rock-salt
Calcareous Spar
Plate Glass
Smoky Topaz
Carbonate of Lead
Alabaster
Alum

Sulphate of Copper

Rays Passed.

92

62

62

57

52

20

12

0

From the preceding tabulated results, we conclude that some substances, more or less impervious to light, as the topaz smoked, is tolerably pervious to heat; while some substances little pervious to heat, as alabaster and alum, are very diapharous. These experiments would lead also to the conclusion, that there is no point of relationship between the diathermous and the diaphanous powers of bodies.

Effect of Polish.-The diathermous power of a screen incresses with its degree of polish. Thus, M. Melloni found that the indications of his apparatus varied from 12° to 5o Centigrade, by interposing screens of glass of the same structure and thickness, but different in the nature of the polish-that is, in being more or less ground.

Ffxt of Thickness.-The quantity of heat which passes M. Prevost, at Geneva, and M. Delaroche, in France, in through a diatermeus screen decreases as the thickness inIsil and 18:2, discovered many of the phenomena which creases, but the absorption is not proportional to the thickCalbermous botics exhibit; but it was not till 1882 that M. ness. In general, the absorption takes place in the first layers or costs of the thickness. Beyond a certain thickness the Mellon by means of an ingenious thermometric apparatus to de deceatier descridol, gave out a complete theory of the dia- quantity of heat transmitted tends to remain a constant quanthermous poperies et sous and liquids. In his experiments, tay, even when the thickness continues to increase. M. Melthisphospheremployed £ve sources of heat, viz. :—1st, a Loon has proved this fact by experimentig on plates of crown catel in that is, are natiout a glass, with a reflector, and wuà a s e curret of air; 2nd, an Argand, lamp, that is, one w: ha cass, and a dente entrent of air-such are the Cave impet dod, a spiral platinum wire kept at a red-heat, in the fame of a sperdslamp, fib, a small hallow copper cube, į Nackomoc on the exterior, and fund with water kept at the da te parts die a correr place blackened and heated to boat 460 Curugrade by the à me of a spint mp. Thus te chinong socce the an hermous plaice and the Routers on heat, M. Me, ora has proves the facts about to be Chưa mod y ng thư Downs Power-The causes which, mod y the Gathermous power of doù æ sre six in number:

glass whose thicknesses were as the numbers 1, 2, 3, and 4; and he found that out of 1,020 rays of incilent hest, these plates permitted the following rays to pass respectively; viz., 19, 175, 558, and 549; and the differences of these numbers tend to become nero,

Ffeet of the Nr of Smerce.—The increase of the number of the screens through which calorie passes, produces an effect aragous to the increase of the thickness; that is, the absorption increases less rapidly than the number of the screens; or, in our words, the quantity of heat absorbed decreases from one screen to the following one. Moreover, if several plates of the same kind are placed together, they stop mort beat than a single plate of a thickness equal to the sum of

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