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139. In general, the positions of the grammalogues, ABOVE, ON, and THROUGH the line, are determined by their vowels; and in the case of a word of more than one syllable, by its accented vowel. The positions of words, as determined by their vowels, are:-For perpendicular and sloping strokes, 1st position, ah, aw, i, oi, wi, ABOVE the line; 2nd position, a, ō, ON the line; 3rd position, ē, 00, ow, i, THROUGH the line. The three positions for horizontals are respectively above, upon, and under the line.

140. Vowel logograms have but Two positions: 1, ah, aw, i, oi, wì, ABOVE the line: 2, ā, ō, ē, oo, ow, u, ON the line. A third position, UNDER the line, for è, oo, ow, u, would not be distinguishable from the second when writing on unruled paper.

141. All grammalogues are written IN POSITION in accordance with the above rules, and are thus easily remembered, except

IRREGULAR GRAMMALOGUES.-CLASS 1.-Words of frequent occurrence are written ON THE LINE for the sake of convenience. Those

of the Corresponding Style are:-are, be, been, dear, do, equal, for, from, give, good, have, him, himself, if, improve-d-ment, it, Lord, mere, Mr, near, Phonography, shall, thing, think, upon, was, we, which, will, your.

come,

CLASS 2.-Words which in their proper position would clash with some other grammalogue, namely, the one which is placed immediately under it, in the alternate lines given below. They areadvantages, any1, English', go1 (and ago), in', me', more1, number3, joy (in reporting,) no, thing, no, him, mere, member, O', over1, own, particular1, read', this", those1, though', truth2, with1, he, ever, no, opportunity, word, these, this, they, true, when. 142. Phonography may be written on plain paper, or on paper ruled with either single or double lines. Our own practice is to em-1 ploy either plain or single-line paper: we find the double lines perplexing. The three positions for logograms on double-line paper are distinguished thus:-1, If down or up strokes, through the top line; but if horizontal or half-length sloping, under it; 2, on the bottom line; 3, if down or up strokes, through the bottom line, and if horizontal or half-length, under it.

LESSONS IN ITALIAN.—IX. VII. THE ACCENTS (continued).

2. THE ACUTE ACCENT.

THE acute accent has been adopted by modern authors as the mark to show the difference of meaning in some words of the same spelling, though differently pronounced, which words, without the acute sign, might occasion confusion and ambiguity, particularly in the case where words of more than one syllable terminate in the diphthongs ia, ie, and io, and from the use of the acute sign over the i, and the necessary stress laid on the syllable thus accented, acquire a different signification. But

even in words ending in io and ia, and presenting no ambiguity, the acute sign is not unfrequently placed merely to indicate that the letter i does not make the two terminating vowels o and a in conjunction with the i diphthongs, but that they are separate syllables. It is a characteristic of the acute sign that it can never be used in final letters, as the grave accent is used. But the use of this accent is, generally speaking, not regulated by invariable rules, and is frequently left to the discretion of the writer. I need not say that the acute sign, which I have adopted in these grammatical instructions, exactly answers the purpose for which it has been introduced by Italian writers, with this difference only, that I shall use it throughout the whole course of the grammar, while they place it merely on some words to avoid ambiguity,

I shall only give a list of words where it is more generally used, some of which I have already quoted in the preceding pronouncing tables :-Natío (nah-teé-o), natía (nah-teé-ah), natal, native; restio (rai-steé-o), restive, stubborn; stantío (stahnteé-o), old, stale, fruitless; leggío (led-jeé-o), reading-desk, a painter's easel; ubbía (oob-beé-ah), bad presage; malía (mahleé-ah), sorcery, enchantment; bastla (ba-steé-ah), bastion; strofinio (stro-fee-née-o), scouring, rubbing; mormorío (morr mo-rée-o), buzzing, murmur; rovinío (ro-vee-née-o), great noise; |fiócine (feeô-tchee-nai), skin of raisin-stones; zúfolo (tsóo-fo-lo), a whistle; margine (máhrr-jee-nai), scar, edge, margin.

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The reader will have remarked that the circumflex & in the above examples has the open sound; and thus this marking of those words on the part of modern Italian authors agrees with the sign that I have uniformly adopted to mark the open or second sound of o.

I cannot begin my exposition of the grammar of the language without first offering some remarks or the use of the apostrophe present my lessons on pronunciation. Some supplementary and in Italian, which, with the general table, will conclude for the important pronouncing tables will be given at the end of the

grammar.

VIII.-THE APOSTROPHE.

The apostrophe is essentially different from accent, and indicates that the word on which it is placed has been deprived of a vowel or of a syllable. Where, therefore, for the sake of harmony, at the beginning or end of a word, a vowel is omitted because the preceding word terminates with a vowel or the subsequent word begins with one, the apostrophe must be placed. It can never be used in the middle, and all omissions and contractions in the middle of words must be written without this sign. For example: l'amore (pronounced lah-mó-rai), love (for lo amore); dell' anima (del-láh-nee-mah), of the soul (for della anima); dall' uomo (dahl-lood-mo), from man (for dallo uomo); capo d' opera (káh-po dô-pai-rah), a masterpiece, an odd man (for capo di opera); s' io posso (sée-o-pôs-so), if I can (for se io posso); pens' io (pen-sée-o), I think (for penso io); sopra 'l letto (só-prahllêt-to), upon the bed (for sopra il letto); sotto 'l cielo (sót-toltchê-lo), under the sky (for sotto il cielo); e 'n questo, e'n quello (en qwai-sto, en quél-lo), as well in the latter as the former

(for e in questo, e in quello); tra 'l si e'l no (trahl see el nô), between yes and no, that is, hesitating (for tra il sì è il no).

I may here remark, that the use of the apostrophe at the beginning of a word is more frequently found in poetry than in

prose.

It is necessary to bear in mind the distinction between the apostrophe as a sign of elision, and the abbreviation of words where letters are omitted without the use of this sign. I consider it necessary to state some elementary rules with respect to the abbreviation of words.

1. The final vowel of any Italian word may be, and always without the use of the apostrophe, omitted, if it is immediately preceded by one of these four consonants, l, m, n, and r, the socalled liquid consonants or liquids, and if, at the same time, the subsequent word should commence with a consonant, except the s impure, as the Italians call it; that is, s followed by another consonant; as, spirito, spirit; seettro, sceptre. For example: il carneval passato (il kahrr-nai-váhl pahs-sáh-to), the last carnival (for il carnevale passato); a man destra (ah mahn dê-strah), on the right hand (for a mano destra); ogni uom tacea (ón-nyee ooom tah-tehái-ah), every man was silent (for ogni uomo tacea); vuol far questo (vooôl fahr kwái-sto), he wants to do this (for vuole fare questo).

2. In words ending with llo, and having the accent of tone on the syllable preceding lo, it is customary to omit the whole of the syllable lo, if the subsequent word begins with a consonant which is not the s impure. For example: bel for bello, beautiful; quel for quello, that, the former; val for valle, valley; cavál for cavallo, horse; uccêl for uccello, bird; fratel for fratello, brother; tranquil for tranquillo, tranquil; cervel for cervello, brains; ruscel for ruscello, brook, etc.

3. The abbreviations or omissions of the final vowels mentioned in the two preceding rules can never take place in that part of a sentence which requires a pause, that is, before a comma, colon, or period. It is, therefore, not allowable to say Ella ha una bella man, she has a fine hand, but mano; not chi è quel Signor? who is that gentleman? but Signore, etc.

Other important rules with respect to abbreviation I shall state and comment upon as examples occur in the course of the grammar, and I shall now content myself with this concluding remark, that all abbreviations in the Italian language, whether made with or without the apostrophe, are made merely for the sake of harmony and to avoid hiatus, that is, a prolonged opening of the mouth by the recurrence of vowels. But as perspicuity is of greater importance than harmony, this general rule may be safely laid down, that abbreviations should not be used without absolute necessity, and that those should be specially avoided which would tend to ambiguity.

I will here give a general and concluding pronouncing table, showing the most complicated combinations of vowels with consonants of the whole of the Italian language :

Chio, keeo or keeô.

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Pronounced.

nnyo or nnyo. nnyoo. Guo, gwah.

gwai or gwê. gwee.

Italian.

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Cio,

teho or tchô.

Gno,

Gnu,

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Gue,

Gui,

Chiu,

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Ga,

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Go,

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Gu,

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Ge,

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Gi,

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Ghe,

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Ghi,

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kwai or kwê. kwee.

Gia,

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Gie,

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Gio,

Gin,

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Gla,

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Gle,

glai or glê.

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Gli,

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In my next lesson I shall enter on the grammar proper of the Italian language. In fulfilment of my promise to follow the natural method to teach, as it were, the language as it is formed in the mind, I shall first speak of nouns, and other kinds of words allied to nouns, and then proceed to explain the verbs and their various inflections. Two methods are open to choice, each of which has its zealous advocates in tuition. Some would confine themselves strictly to theory in grammatical teaching; others as exclusively to practice in the earlier stages of the instruction. If we adhere strictly to the theoretical exposition, the progress of the pupil is sure, but slow; if we are merely practical, the pace may be rapid, but the attainments are superficial. I shall endeavour to blend the two, and while I, as concisely as I can, explain all the principles and rules of the language, I shall constantly strive to impress them on the minds of my pupil-readers by practical exercises on each rule as it occurs. I shall, in this part of my labour, endeavour to improve on a modern invention of Germany, the country, perhaps, most distinguished for scientific method in education. It should be the aim of every educator so to teach, that his pupils may regard the instruction as relating to a living language to be acquired by the tongue, and not merely as dead writing to be comprehended only by the head. From the very outset of these grammatical lessons my pupils will learn to form sentences, so that as the head acquires knowledge of its principles, the tongue will grow familiar in the practice of the language. In thus uniting practice with theory, I shall, of course, be obliged in one class of the exercises to anticipate the systematic exposition of principles, but I shall only do so with strict regard to the progressive knowledge of the student, and I shall specially adapt the exercises to that end, and perhaps thereby succeed in more firmly impressing even the rules anticipated on the mind. The pupil must bear in mind that he is now about to learn to speak as well as to read the language of Italy.

With regard to the selection of exercises, I shall not scruple, in addition to my own, to make a free use of examples which have passed the test of years of experience in the best schools of Italy and Germany. I am more anxious to serve the interests of my pupils than gratify a literary vanity; and even were I to make an effort at originality, by the preparation of exclusively new exercises, one man could hardly hope to excel the united labours of many grammarians in this direction.

The exercises ought to be read over frequently, and always aloud; and if committed to memory, so much the better for the knowledge of the student.

As I have so very fully explained the elementary principles of pronunciation, even at a length which may have damped the ardour of more impatient readers, it will not henceforth be necessary to give the pronunciation of each Italian word used. Should any doubt occur, the student can always refer to the pronouncing lessons or to the general table which precedes these remarks. As it is, however, most desirable that the reader should have as much assistance as possible, I shall aid him by a new, and, I believe, a most effective method, namely, by dividing each Italian word used into syllables, for the most part, as the words are divided in Italian spelling and writing. I shall not omit to mark the accent of tone with the acute sign or with the circumflex sign over the e and o; signs, be it remembered, not used in Italian writing or printing, with the exception of the words commented on in my remarks on the use of the accent. The grave accent will, henceforth, always be placed where the usage of writing requires it, and in such cases it will serve, likewise, to denote the accent of tone. I am induced, by three reasons, to adopt this method of dividing words into syllables :First, to correct the great fault of Englishmen in pronouncing Italian by slurring over words, the component sounds of which are unfamiliar to the ear. By this means, the learner will be in some measure compelled to do justice to each syllable.

Secondly, it will be a practical aid to the memory. This dwelling on the ingredients of the word will impress the word itself better on the memory.

Thirdly, it will be useful in the case of compound words, in indicating at once the elementary constitution of the words.

PNEUMATICS.-III.

CUP OF TANTALUS-INTERMITTENT SPRINGS-SABBATIC RIVER -BAROMETER-WHEEL BAROMETER.

AN ingenious scientific toy, known as the Cup of Tantalus, has been constructed, and acts on the same plan as the common syphon. It is, in fact, an intermittent syphon, and is useful as serving to explain the action of intermittent springs. A syphon is inserted in a cup so that its longer limb may pass through an aperture at the bottom, and the highest point of the bend may be rather lower than the brim. If water be now allowed to run into the vessel, it will fill as usual until the water reaches the level of the bend. The syphon will then begin to act, and if its size be the same as that of the supply-pipe, the water will remain at that level; if, however, the syphon carry it off more rapidly, the vessel will be emptied; the syphon will then cease to flow, and the vessel will again be filled. An intermittent flow will thus be produced. Various modifications may be made in the construction of this vessel. Sometimes the handle is made hollow, and thus serves as a syphon, and, when thus made, the reason of the cup emptying is not so easily seen. Sometimes, too, an open tube is inserted in the vessel, and another, closed at the upper end, is inverted over it: all, however, act on the same principle.

that they should be well washed, and the more frequently the water is changed the better will this be done. A vessel is therefore made with a small depression at the bottom separated from it by a grating. From this a syphon rises about threefourths of the height of the vessel, and then passes through the side. The water is allowed to enter in a constant stream by a pipe about half the size of the syphon, and so placed that the water enters in such a direction as to keep the contents in a constant state of motion. As soon as the vessel is filled to the level of the bend, the syphon commences to work, and in a short time empties the vessel, the false bottom causing the photographs to be left quite dry, a thing of great importance, as, thereby, the last traces of the chemicals employed are more easily removed. The vessel then fills again, to be once more emptied in the same way.

Fig. 7.

We shall now be able to understand better the action of intermittent springs, many of which exist in different parts of the world. In England there is one known as Weeding Well, in the Peak of Derbyshire; others exist at Giggleswick, in Yorkshire, and near Torbay ; but the most noted of all are found in Palestine. Josephus speaks of a stream called the Sabbatic river, which flows one day, and then is dry for the next six days. Pliny refers to the same; but he makes it flow for six days, and rest on the seventh. The existence of such a river was long doubted; but modern travellers say that they have discovered a small stream which seems to be that referred to. Now, however, it is dry for two days, and flows on a portion of the third; but this alteration may be easily accounted for. The annexed diagram will serve to explain the action of the spring. A large reservoir is supposed to exist in the hill from which the stream issues. This is supplied by the rain, which percolates through the sides of the mountain and, by various inlets, finds its way into the cavity.

A syphon-shaped channel is also supposed to exist, of such a capacity that it can carry off the water more rapidly than it enters by the different feeders. Now it is clear that the water will go on accumulating, but none will flow till the cavity is filled to the level of the bend in the channel. As soon, however, as it attains this level, the syphon will begin to act, and the stream will flow until the reservoir is empty, when air will enter the syphon, and it will cease to act until the cistern shall again be filled, when the same effects will be repeated.

We have now noticed several important results of the pressure of the air, and the construction of machines which act by means of it; but we have not yet seen the mode of determining how great this pressure really is. We have, however, stated it to amount to about 14lbs. per square inch, and must now show a proof of the fact.

We might take a surface of known area, and having, by means of an air-pump, removed the air from under it, ascertain the pressure by a spring balance. This plan would, however, be very difficult and uncertain, as it is impossible perfectly to remove the air, and it would be very difficult to ascertain the pressure exerted on the balance. There is, however, another mode of ascertaining this, which depends on the fact that a liquid transmits pressure equally in all directions. If we take a glass tube about a yard long, sealed at one end, and, having filled it with mercury, place the thumb over the open end, and invert it into a cup of mercury, we shall find that a small part of the fluid will run out, but that the tube will remain filled to a height of about 30 inches above the level of the mercury in the cup. This experiment was first performed about the middle of the seventeenth century by Torricelli, after whom the empty space left at the top of the tube is known as the Torricellian vacuum. Now, if we consider the forces at work, we shall see that the air presses on the surface of the mercury in the cup, and its

pressure is transmitted through this to the mercury in the tube. The upper part of the column is, however, shielded from this pressure by the closed tube, and, since the whole is in equilibrium, the pressure produced by the air must be exactly equal to that produced by the weight of a column of mercury 30 inches high. Let us suppose the tube to have an area of one square inch: the pressure then on this area, and accordingly on every equal area, will be equal to the weight of 30 cubic inches of mercury. Now a cubic inch of water weighs 252-5 grains, and the specifie gravity of mercury is 13.59; a cubic inch of it weighs, therefore, about 3441 grains, and 30 cubic inches weigh about 143lbs. This, therefore, is the pressure exerted by the air on every square inch of surface when the mercury stands at a height of 30 inches. In this climate the mean height is rather under this, being about 29-9, and the pressure, therefore, is a little over 14 lbs.

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Fig. 8.

The smaller the cistern, the more frequently will the water flow. Hence it is quite possible that the statement of Josephus about the Sabbatic river may have been true, but that the cistern has been gradually filling up, so that now it flows once in three days instead of once in seven. An enlargement of the channel by which the water issues, or an increase in the supply brought by the feeders, would produce the same change.

The Pool of Siloam is another instance of a spring of this kind. Dr. Robinson states that, when he was there, he observed the water rise nearly a foot in five minutes, and that he was informed that such rises occurred frequently, sometimes two or three times in the course of a single day, but at other periods only two or three times a week.

An ingenious application has been made of this principle in an apparatus constructed for the purpose of washing photographs. In order to ensure permanency in prints it is requisite

This simple instrument is one of the most important in the science of Pneumatics; we must, therefore, give a little atten tion to its mode of construction and action. It is called the Barometer or "Weight-measurer," though, in reality, it is the pressure and not the weight of the air which it records.

That it is the pressure of the air which supports the column of mercury is easily seen, by the fact that if we make an opening so as to allow the air to press on the surface of the mercury in the tube, it will immediately fall to the level of that outside. A more conclusive experiment as to this point was devised by Pascal. He said that if it was the weight of the air which sup ported the column, then, if the barometer were taken to any elevation so as to leave a part of the atmosphere below it, the

mercury ought to stand at a less height. The experiment was accordingly made. The instrument was conveyed up a mountain, and the height noted at intervals, when it was found, as he had predicted, to diminish gradually as the elevation increased. This experiment was rightly deemed conclusive.

The barometer is of very great use in all meteorological observations, and therefore great precautions have to be taken to ensure its accurate action. In the first place, the mercury used in its construction must be absolutely pure, for if, as is usually the case, zinc or some other metal be present in the mercury, they will render it lighter, and the column will therefore stand at too great a height.

Then, too, mercury often absorbs a small quantity of air, small bubbles also creep up along the side of the tube, and these depress the column and cause the reading to be less than it should be. The utmost care is therefore required, in instruments intended for very accurate observation, to guard against these causes of error.

Fig. 9.

H

The usual way of filling the tube of the best barometers is to pour in a small quantity of the mercury so as to fill the tube for a few inches, and then boil it to drive off the air; after it has cooled, a second portion is introduced and boiled, and so on till the whole is filled. The main objection to this mode is, that the heat sometimes renders the glass much more liable to crack. A plan was accordingly devised, and is used at the Kew Observatory, which seems superior and avoids this risk. The tube is drawn out to a small diameter at each end; these ends are turned up, and one of them scaled. The air is then removed by a very good air-pump, the tube being meanwhile heated by a spirit-lamp to prevent the air adhering to the glass. When exhausted, this end is sealed, and the other end broken under the surface of boiled mercury. The pressure at once forces it up the tube, which is held in an inclined position, and the small amount of air left in it is driven into a bulb blown in the fine part of it. The tube is then sealed by a spiritlamp at a point a little below this, and all air is thus excluded. The other end is then bent slightly upwards, so that the air would have to travel down the bend before it could pass up the tube to impair the vacuum. A contrivance, known as an air-trap, is also placed in some barometers for the same purpose (Fig. 9). The part A of the tube is drawn out so as to leave only a small aperture, and is inserted into an enlarged portion blown on the other part, as shown in the figure. In this way a cavity is formed, in which any air that may enter the tube will accumulate, and it can be removed when necessary. The total absence of air is easily told by the ringing sound which is caused when the tube is inclined so as to cause the mercury to strike against the top.

B

Fig. 12.

W

Now in many barometers this is altogether neglected, and their readings are inaccurate on that account. In some the scale is graduated to allow for this, an inch, according to the marks on it, being only ths of an inch. Sometimes, too, the scale is made movable, the lower end being adjusted by means of a rack and pinion, so that it just touches the surface of the mercury in the cistern. A better plan, however, is that represented in the figure. A second bottom is fixed in the cistern, which can be raised or lowered by a screw s. A pointer, i, is fixed to the side of the cistern at such a height that the graduations are measured from its lowest point. By means of the screw the level is then adjusted till this point appears exactly to meet its own reflection in the mercury, which is then said to be at its neutral point. Whenever, then, a reading has to be taken, this adjustment is first made, and then the true height is shown. For ordinary purposes, however, if the area of the cistern is very large as compared with that of the tube, this correction need not be made.

It may at first be thought that if the tube were made smaller, or if the upper part were of a smaller bore than the

Fig. 10.

It will be well now to note the modes in which this barometric tube is arranged so as to show the variations in the pressure. It is frequently made to dip into a vessel of mercury, v (Fig. 10), and a scale, c D, graduated accurately, is engraved on the tube itself or else on the case containing it. These gradua tions usually extend from 27 or 28 inches to 31, the variations in the height being always, in this country, confined within these limits. When it is required for ascertaining the height of mountains, as will presently be seen, the graduations extend nearly the whole length of the tube. The readings by this scale will not, however, be accurate, for when the mercury in the tube has fallen one inch, the level of it in the cistern, if that have ten times the area of the tube, will be raisedth of an inch by the additional quantity of mercury now contained in it. The total effect, therefore, will be that the mercury has fallen 1th inch, that is, it stands 1 inches less above the surface of that in the cistern than it did.

30

V

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S

Fig. 11.

lower part, the mercury would rise to a greater height, and thus more accurate readings could be taken. This, however, is not the case, for, as we saw in our lessons on Hydrostatics, the pressure depends solely upon the depth of the liquid, and is quite independent of the shape or size of the vessel.

If a lighter liquid be used, the column will be longer, and the variations more easily and quickly seen. Various liquids have, therefore, been tried, and water was one of the first. Now, as mercury is 13 times heavier than water, a column of the latter, to produce the same pressure, must be 13 times as high. The tube in the water barometer must, therefore, be about 35 feet long, and is, on this account, very unwieldy. Several such have been constructed; but they are found to get out of repair in a very short time. Water dissolves a considerable amount of air, and thus, even though the water has been boiled to remove it, some will enter, and, passing up the tube, cause the level to fall. Water also evaporates to a small degree at ordinary temperatures, especially in a vacuum, and hence vapour accumulates at the top of the tube and produces a similar effect.

Many very skilful arrangements have been made to guard against these errors; and a barometer was constructed some time since by a gentleman in Birmingham, which embraced nearly all these. The surface of the water in the reservoir was covered with oil to the depth of an inch or two, so as completely to exclude the air; the upper part of the tube was prolonged into a spiral coil, which could be cooled so as to condense the vapour; the utmost care was also taken in filling the tube. It was then found to be very much more sensitive than the common mercurial barometer. During a storm, while the latter only showed a slight variation, this showed extensive oscillations rapidly succeeding each other. It was found, too, that changes in the air were shown by this a full hour sooner than by the ordinary instruments; but, despite these facts, the common barometer is the more to be depended on, in the long run, as the mercury only evaporates in a very slight degree, and is easily obtained perfectly pure. By means, too, of a sliding scale called a vernier (Fig. 11), the height can with ease be read to within of an inch, and this is sufficient for most purposes. The vernier consists of a pointer attached to a scale, which can be moved up and down so as to adjust it exactly to the level of the mercury. The ordinary scale is divided into inches and tenths of an inch; the vernier, however, is exactly 1 inches long, and is divided into ten equal parts. Each division is therefore th of an inch. If any division of this be

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made to correspond with one on the ordinary scale, the adjacent divisions on each will be of an inch apart, the next, and so on. The divisions on it are marked downward, 1 being at the top. Now we will suppose the mercury to stand as shown in the figure; the pointer is adjusted to the level, and we immediately see that the height is somewhere between 29.8 and 29.9. We now run our eye down the vernier till we find the division which is most nearly even with one in the other scale; this is the one marked 6. The level is therefore above 29'8, or 29.86.

In a barometer the mercury always clings, to a certain extent, to the side of the tube, and thus seldom presents an even surface; the readings ought, therefore, to be taken from the height of the centre of the column. There is one great advantage derived from this, viz., that we can see at a glance whether it is rising or falling. If it is rising, the surface is convex, or higher in the middle, that at the sides being kept back by its adhesion to the tube; while if it is falling, the surface is

concave.

The cistern barometer which we have been considering is the more common form of the instrument. The wheel barometer is, however, often used, and we must therefore give a description of it (Fig. 12). It consists of a large dial-plate fixed near the lower end of an oblong case, and round it are graduations from 28 to 31 inches, and also the words Stormy, Much Rain, Rain, Change, Fine, Set-fair, and Very Dry. A hand, turning on an axle, points to different parts of the face, and thus gives the readings. If we open the case behind, we shall see that the main difference is that the end, instead of opening into a cistern, is turned up to a height of 6 or 7 inches, and a float & rests upon the surface of the mercury in this limb. This float is attached to a cord, which passes over the wheel H, and has a small counterpoise, w, fastened to the other end. The hand seen on the dial-plate is attached to this wheel. When the mercury falls in the limb AB, it rises in the shorter limb BC to an equal extent; the float is therefore raised, and the weight w turns the hand, which thus shows the height. On the mercury falling again, the weight of a more than balances w, and brings the hand back again. In this form of barometer the surface of the mercury cannot be seen so as to tell whether it is rising or falling; an additional hand, worked by a small handle below, is, however, placed on the dial, and registers the position at any time, and thus shows at once whether it has risen or fallen since it was last set.

The upturned end of the barometer is sometimes enlarged, and a stop-cock inserted just under the enlargement, so that by inclining the tube it becomes filled up to the top; the tap may then be closed, and the superfluous mercury poured away. In this way it may be carried about with safety, as the tube is completely filled, and all vibration thus prevented. On turning the tap, and placing the tube in a vertical position, the pressure will at once be shown. Care must, however, be taken that the tube is vertical, as otherwise the mercury will appear to stand at a greater height than it really does. The mode in which the barometer is used as a means of foretelling the weather we must defer to our next lesson.

A brief allusion has been made to the "water barometer," by which the variations of the weather may be more readily detected, but which is inconvenient on account of its great length, and consequent unwieldiness. Among curious constructions on this principle may be mentioned the "water barometer" of Otto Guericke, which was attached to a wall with a toy in the form of a man floating on the water. The entire tube was hidden behind some wainscoting, so that the little figure was only seen, appearing and disappearing, as the weather was fine or the

reverse.

LESSONS IN MUSIC.-XXI.

ORGANS OF THE HUMAN VOICE-PITCH-QUALITYSTRENGTH-FORCE, ETC.

WE propose to collect together in this lesson a large amount of information on the subjects of the different kinds of voices, singing in "parts," and good enunciation. We must refer our readers for fuller information on these topics to Müller's "Physiology," Book IV., Section 3; the articles "Larynx," "Voice," and "Stammering," in the "Penny Cyclopædia;" Sir Charles

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Bell's article on the voice in the "Philosophical Transactions for the year 1832; and Dr. Rush's great work (American) on the "Philosophy of the Human Voice." The CHIEF INSTRUMENT of voice is the larynx, which we may feel with the hand outside, as a little lump, in the upper part of our throats, moving with almost every utterance of voice. It is a small box placed at the top of the trachea or windpipe. Its walls are of cartilage or gristle. Its upper opening is protected by a little valve, called the epiglottis, which falls back upon it in every act of swallowing. At the lower opening are two elastic membranes, one depending from each side, which can be stretched to any degree of tension required, and can be made to meet each other (closing the lower opening) through their whole length, or through any part of it. Various muscles, attached to the walls of the larnyx, in obedience to nervous action and the mind's will, regulate these movements.

These elastic membranes, sometimes called the vocal chords, are the source of voice. During ordinary breathing they rest, relaxed, against the walls of the larynx, but in the production of voice they are brought into such a position as to vibrate freely in the air, as it ascends from the lungs (much like the tongue of any reed-instrument), and this vibration makes the breath vocal.

The voice of one individual differs from that of others in PITCH, in quality of TIMBRE, as the French call it, and in power or STRENGTH.

The PITCH of a sound depends on the degree of tension given to the vocal membranes, and on the length of the parts which are left free to vibrate-just as in the harp, violin, and guitar. In females and boys, whose voices are naturally higher than those of men, the larynx is placed higher in the throat, and is also smaller, so as to make the vibrating membranes shorter. When a boy's voice "breaks," the larynx gradually takes a lower place in the throat, and also enlarges in size, so that the voice necessarily becomes about an octave deeper. Müller states that the vocal membrane in the male is half as long again as in the female-as three to two. To produce a given note (say D below the staff), the male voice, especially if a bass, would require strong tension of the vocal membranes, but the female voice would produce the same note with very little tension, because its vocal membranes are shorter.

The TIMBRE, or quality of a note (which is so different in different individuals), is much affected by the form of the airpassages above the larynx. Thus we are sometimes able to imitate the voice of others, not only in reference to its peculiarities of pitch and inflection by movements of the larynx, but even in its "timbre" by certain conformations of the mouth. It is this difference of shape in the resonating tube which makes the difference between well-known bass instruments of the same length, and yielding sounds of the same pitch, as between the thick euphonium and the thin baritone, and between the thick sax-horn and the thin trumpet. The discoveries of Professor Helmholtz have thrown much light on this subject of timbre or quality of tone. By altering the shape of the mouth you can produce the sombre and clear resonances of which Garcia speaks.

The general STRENGTH of a voice appears to depend upon the vibrating power of the vocal membranes, the size of the organ, and the capacity of the chest. We know how easily a slight inflammation, or other affection of the mucous membrane lining the larynx, weakens the voice. The voices of old persons are made tremulous by the loss of nervous and muscular power.

The special FORCE or loudness given to an accented note may be occasioned, Müller thinks, by relaxing the tension of the vocal membranes while we increase the force of the air-current. Sir Charles Bell speaks of the back of the mouth and the veil of the palate (the soft palate) as playing a most important part in giving the delicate impulses of accent.

Correct tune requires a mental effort. 'Man," says Müller, "like the singing bird, learns unconsciously the different internal changes in the state of the larynx, and the different muscular actions necessary for each note. Sounds accidentally uttered, and the muscular actions which accompany them, become associated in the sensorium, and afterwards readily excite each other when a melody is to be imitated." Correct tune, therefore, depends upon the skill with which the sound is perceived and its "idea" retained, and upon the accuracy with which the mind can command and combine the various muscular movements

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