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cut circular-a flat piece of tin or sheet-brass will do as well; place one hand upon this to prevent it falling off, and with the other hand lift the jar and invert it into the dish. In Fig. 17 it will be seen that the jar stands on two pieces of slate, parted with about half an inch between them, thus allowing room for the delivery tube to pass beneath. When a jar is full of the gas, pass a small plate beneath its mouth, and lift it out of the water; it will stand in the plate as long as required, if the hollow of the plate be left full of water. Another jar should be standing in the dish ready to be filled; and as with one hand the full one is removed, with the other the second one should be placed

Fig. 17.

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chloride and oxygen.

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where it is diluted with nitrogen. This the following experi-
ments will show:
1. Twist a wire round a piece of charcoal (Fig. 19). Take
one of the jars of gas standing on the plate, and replace it
in the dish of water; remove the plate, and in its place put the
circular piece of
glass; lift it
from the water
and stand it on
the table, mouth
upwards; hold
the charcoal in
the flame of the
lamp until some
parts of it are
red; with one
hand slide the
glass off the
mouth of the jar
sufficiently to
admit of the en-
trance of the

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Fig. 19.

charcoal, and the charcoal will burn brilliantly in forming with the oxygen carbonic acid gas (CO2).

Do not place the flask on a cold substance while it is hot, but when cold fill it with water; after a few shakes pour it into a 2. Place in the "deflagrating spoon "-which is a small metal tall jar, and add more water. The potassium chloride is very cup soldered to a piece of wire (Fig. 20)-some sulphur; light it soluble, and the unaltered MnO, goes to the bottom; let it-it burns with a pale blue flame; introduce it into a jar of stand all night, then pour off the "supernatant liquid;" fill the oxygen-it burns brightly into SO, (sulphurous acid), which jar again with water, and again let the MnO, subside; pour off causes the well-known suffocating smell. the clear water, which contains the last traces of the KCl, and throw the MnO, upon a filter, and afterwards dry it; it is then fit again for use. This will give the student some practice in manipulation, but practically it is not worth the trouble, since the MnO, is so cheap.

3. Oxygen may be got, when large quantities are required, with more economy from the black oxide of manganese itself; but since great heat is required, an iron bottle must be used, as in Fig. 18. In this bottle the delivery tube is passed through a cork in the end of the pipe. The retort is filled with manganese broken into lumps about the size of a pea; then the pipe is screwed in, and, to ensure perfect tightness, the screw is luted with white lead.

Fig. 18.

The action is

3MnO, Mn,0, + 0,;

=

that is, the peroxide has been by the heat reduced to a lower oxide.

4. A process which answers well, and which is more economical than that in the second, is the following:-Take 3 parts by weight of pulverised potassium bichromate (K,O,2CrO,-1 atom of potash and 2 of chromic acid), and 4 of sulphuric acid (H,SO); heat it in the Florence flask, and the chromic acid parts with half its oxygen.

K,0,2CrO, +4(H,SO,) = K,,SO, + Cr,,3SO, + 4H,0 + 30. The compound under the line is chrome alum.

Combustion is simply chemical combination, and when this combination is violent, sufficient heat is developed to produce fire.

The affinities of oxygen are remarkably strong, and it is capable of entering into combination with every body in nature except Fluorine; therefore fire is generally oxygen entering into combination with the body burning; though we shall find instances of this phenomenon in which oxygen takes no part. In the fires of our houses the oxygen of the air is combining with the coal, which is carbon, to form an invisible gas, carbonic acid gas (CO), which passes up the chimney. Hence we say that oxygen is the great supporter of combustion. Of course combustion will be more violent in the pure gas than in the air,

3. Repeat this experiment with phosphorus. The student is advised to use the red amorphous phosphorus, which is not so inflammable as the stick phosphorus. An intensely brilliant. light is emitted during the formation of the white fumes, which are phosphoric acid (P,O,).

4. The following experiment is very illustrative of the fact that burning is chemical combination. Take a piece of fine iron wire-such as that of which "ribbon-wire" is made; coil it into a spiral, round a pencil; stick the end of it into as small a piece of cork as you can; dip this into any inflammable liquid, such as naphtha; pass the other end through a hole in a disc of tin; light the cork, place it in a jar of oxygen, as in Fig. 21, and the wire will burn with beautiful scintillations into Fe,O which is the same oxide of iron as the lodestone. It is better to fit a piece of cardboard in the bottom of the jar, and leave about an inch of water in it: for the fused oxide is so hot that if it touch the glass the jar will crack.

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Fig. 20.

From the above modes of preparing oxygen we may take examples of one method of finding what weight of the substance is required to give a certain quantity of another. Take the equation

KCIO,

=

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the atomic weights of these elements are

39 1+355 + 48 391 +355 + 48
122.6 746 + 48.

That is, from every 122.6 parts by weight of potassium chlorate,
48 parts by weight of oxygen come off;

kilogramme of the salt gives off '392 of
the gas, or nearly kilogramme.
Again-

or, from 100, 39.2 come off; that is, 1

3MnO, Mn,0,+20.
3x55+3×2× 16-3x55+4 x 16+2x16
261229 +32;

that is, from 261 parts of manganese
by weight we get 32 of oxygen, or about

of the weight of the MnO2. But the
commercial black oxide of manganese
is seldom very pure, and usually yields
about half this weight of gas-a pound
giving off about 1,400 cubic inches.
volumes and weights will be given in due time.

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www dated by abbreviation; the word served from the Latin "omnibus," amber of the Latin adjective omnis, that is, every man's carriage-the

beriad mo s, and so it is now generally Mob appears to have been formed

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What Di How called the mob used to be called
A tabble are mobile vulgus, a fickle crew,

1 vulgus, and by contraction, mob.
o not identical. Rabble is the general

aut mở la a collection of persons belonging to tva contracted form of the now more fashiontween alias and eleemosynary there would tion; both, however, come from the same and the former is only a shortened form of the Thick the latter is derived. Well do we remember ut our youthful days, used to signify someLittle did we then suspect that it was 1,444 way of pronouncing the French quelque chose; contemptuously travestied to mimic and ridicule xa in England.

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ne Ando Baxon cyn, kin, offspring, son, signifies Wilkin (Wilkins); seen in another formkm from its signification, has also a diminuin subkin (a lamb's child), or little lamb. What kos diminutives are terms of endearment. hiks may be despised. Sometimes, therefore, mrpriz Glauksiapt; as in manikin.

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Đi xa HCCAP bên to you, Bir Toby.”— Shakespeare.

by one the suffixes already given.

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Audo Maxon les (German, los, destitute of), has has lost a negative force; as, an læs twentig, " " wa wa should say, twenty minus one. Hence +1 345 visa of less is privation or negation. Con14.5 Amparative of little, is altogether a different man also led to understand the true force ged as a suffix; as, motionless, or without Je from death. Two negatives thus make privation of life, and less, the negation of By declare the idea of ever-enduring existence, *** 196 mont roal, the most permanent of all conVARY Once of Deity; life itself.

,

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seems to be double, and to consist and the French diminutive t." It f, hamlet (Anglo-Saxon, ham, home;

As descent, and hence offspring; That, which is beloved; e.g., darling j. hurtling. Hireling is properly J Bevices are obtained by hire.

ades of contempt" ascribed to it by Latham does not y, for it did not originally, belong to the word.

I be a swift witness against those that defraud the hireling in .”—Malachi iii. 5 (compare Job vii. 1, 2; xiv. 6). Sy may be connected with the Latin stirpes, stirps, - so that stripling is a little branch, a youngster. He is but an yonglyng,

A tall, worthy stryplyng.”—Skelton.

Tabe shows that nothing contemptuous belonged to the vizi in the olden time. Consult the ensuing :"Now a stripling cherub he appears,

Not of the prime, yet such as in his face

Touth smiled celestial."-Milton, “Paradise Lost.”

a termination of Saxon origin, having the force of our like, suming an adjective or an adverb; as childlike, childly, German soladi; manlike, manly, manlich. When ly is added a noun, it forms an adjective, as love, lovely; when it is added an adjective, it forms an adverb, as wise, wisely. Such a formation as “henly" (1 Thess. ii. 10) is to be avoided for the sake of euphony.

Ment, from the Latin mentum (as in ornamentum, an ornament; adjumentum, an assistance), through the French ment (as in the French mandement, or Latin mandatum, a command), is a suffir which denotes the result of the act indicated in the verb from which the noun is derived: thus, veir means I veil or cover; and velamen or velamentum is a veil or conering; so aliment (from the Latin alo, I nourish) is a means of morishing, nourishment. Hence, devotement properly indicates not the act, but the result; not the doing, but the state of feeling which ensues from the doing, the devotion. In practice, however, the usage seems reversed. "Her (Iphigenia) devotement was the demand of Apollo."-Hurd. "Oh, how load

It calls devotion genuine growth of night!
Devotion! daughter of Astronomy!
An undevout astronomer is mad.”

Young, "The Complaint."

It is our intention now and then to enliven our lessons with a conversation on English grammar, supposed to be held between an educated man on the one hand, and one whose education is imperfect on the other. We do this because there are many of our readers who may gain much useful information from a lesson brought under their notice in a conversational form, that they may fail to gather from lessons written in the ordinary way. We therefore recommend our readers to study the following dialogue with care, and endeavour to re-write the substance of it from memory when they have read it over three or four times, and noted the principal points in it.

CONVERSATIONS ON ENGLISH GRAMMAR.—I. William. Well, I have failed again; a packer I am, and a packer I must remain, fond as I am of reading, and desirous as I am of getting an employment more suitable to my tastes. And yet, if I had fair play, I could, I am sure, do the countinghouse work as well as some that are there.

Thomas. Not quite, William; true, you are intelligent and trustworthy; you also write a good hand, and are ready at accounts; but you are a very poor grammarian.

William. Not so poor as you think; though I am, I grant, far behind you, Thomas; but then you have been to college, and ought to know grammar.

Thomas. Yes, and I am willing to teach you, for I am sure you will never get forward as you wish, and as I should like to see, until you can write your mother tongue correctly.

William. I know that, and I have studied English grammar; but it is very difficult.

Thomas. Yes, and you still write bad English: for instance, your letter of application for the vacant situation contains not less than three grammatical mistakes, and is enough of itself to prevent your success. How can you expect to rise in the world when you cannot speak and write English? In a counting. house they want their letters written grammatically. It would be a disgrace to a house to send out letters containing errors of grammar like those which you commit.

William. I dare say you are right; and so I must remain a packer.

Thomas. That does not follow; learn the English grammar.

William. A very easy precept, but a very hard job. Thomas. Not so hard as you think. William. Excuse me, I have tried, and I have failed. Thomas. Because you have tried by yourself. William. By myself I must still try, or give it up. Thomas. No, I will assist you, if you will make one more effort. Let us talk over the matter; I think I can make the study easy to you. Once a week we will cc averse together on English grammar, and if you will only reflect in the intervals on what I say, and follow my guidance, I have no doubt you will in time understand the subject thoroughly.

William. I agree, and am very much obliged to you for the offer. Thomas. Oh, never mind the obligation; men should always try to assist each other, and I am very desirous to see you in such a position as your character and talents mark you out for. William. Let us begin this evening.

Thomas. Very well, and you must come to my house every Tuesday evening at eight o'clock, and we will see what can be done. But to begin :-As a fundamental rule, you must observe that grammar is a science in which authority goes a very long way. At first, you will do well to consider that everything depends on authority.

William. What authority?

Thomas. That of the best writers in the language. If you study English grammar, then you take as your authorities or guides such men as Shakespeare, Milton, Dryden, Johnson, Pope, Macaulay. Their practice is your model. As they write, so you must write. Grammar then, you see, is, for our purpose, imitation. Those who write English grammar derive the instructions they offer from the usages of the best English authors, or, as they are termed, the English classics.

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Thomas. Oh, no; every literature has its "classics." The word is derived from " class," and denotes those writers who, by common consent, are placed in the first class. The practice of such writers sets the fashion in the language in which they write, and they are followed by all who wish to speak and write that language correctly. Now you are to suppose that I have studied our English classics, and have hence ascertained how I ought to speak and write. In that study I have been preceded by others. Their conclusions afford me aid. Under that aid I have formed a system of rules, and that system of rules is called "English grammar." English grammar, then, you see, is a science. Science, you know, means knowledge; it is knowledge, the materials of which are systematically arranged; arranged, that is, into a system, arranged in a set order, and with a view to a certain purpose or result; and English grammar consists of a continued set of rules derived from the practice of well-educated Englishmen, so arranged as to form a complete whole, and communicate useful information to the learner.

LESSONS IN DRAWING.-XVIII.

TREATMENT OF REFLECTIONS IN WATER.

IT is not the rule that because we can see the objects we must consequently see the reflections; and, on the other hand, it is very common to see the reflection of an object, or of light, when the eye does not see the object itself, something intervening between the eye and the object, but not between the eye and the reflection. The leading principle, upon which is founded all other data connected with our subject, is that the reflections of all objects and their parts are always perpendicularly beneath the objects and the parts themselves respectively. Fig. 112, a simple subject of posts, etc., will explain this. The top of the post a is perpendicularly over the reflection b, and so with the rest; but it must be borne in mind that the proportion to be drawn of the reflection of an object is regulated by or according to the position of the object, and also with regard to the point from which we view it. If we view the posts (Fig. 112) as they are drawn, perpendicularly and parallel with the picture plane that is, the upper parts neither advancing towards the eye nor receding from it, but exactly over the position of the lower parts-then the reflections will be the same in length, with the slight exception resulting from the perspective of distance. We will endeavour to make this clear by the help of a few problems. In order fully to understand these problems, we recommend the pupil to work them out, and as the principles of construction are the same throughout, we advise him to repeat them with a few of the conditions varied-for instance, greater or less inclinations of the slopes, and greater or less elevations of those objects which are most in advance. Our first subject will be to draw the reflection of a wall (Fig. 113). Let A be the end section of a wall situated on the margin of a river. It is required to show its reflection, B, below the water's

The

William. "Classics!" why, I thought the term "classics was confined to the Greek and Roman authors, such as Homer and edge, CD; 8' being the position of the eye on the horizontal line. Virgil. Draw a line, s1 s2, perpendicularly as much below the base CD as it is above it, making s2 E equal to s1 E. From the upper part of the wall F draw a line to s2, and where this line cuts the base C D in H will give the point through which a line is to be drawn from s1 to meet a perpendicular line from F, which will give the depth of the reflection required. Now in order to apply the above rule in showing the face of the wall and its reflection, we must proceed as follows:-In Fig. 113 draw at pleasure the line a c d b, and repeat this line, with its respective divisions, in Fig. 114; through the several points a cd b draw horizontal lines at right angles with ab; make A B equal to the length of the given wall, and draw the rectangle A GHB; ABFE will represent the wall, EFHG the reflection. pupil must be reminded that the line a cd b in Fig. 113 is the picture plane or medium through which we see the wall, and upon which it is supposed to be traced (see Vol. I., page 72, Def. 3, "Station Point"). We have previously observed that in consequence of the position of the eye being above the reflection, and on a level with some portion of the object, it will repeatedly occur that the reflections of many parts of the solid cannot be seen, although the parts themselves are in sight, and form, perhaps, the most important portions of the object. Let us illustrate this by Fig. 115, which is a mass of masonry, having two slopes, A and B. Having drawn the profile or section G, proceed as in the last case, being careful to draw lines, or visual rays, from every angle to s', and also to s2. Where these rays cut each other respectively in w, t,g, lines from s1 will determine the lengths of the reflection. We must apply this to a front view, as in the former case. Draw the perpendicular line E E1 (the picture plane), and mark the points where the visual rays cut the picture plane in a, b, c, etc. Repeat this line in Fig. 116, and copy from Fig. 115 the distances of the divisions upon it, and proceed with the horizontal lines from these distances as in the last problem. Upon the line marked g, which represents the water's edge, make FG equal to the given length of the wall; d being the horizontal line, and the observer being supposed to stand opposite the centre of the wall, the point of sight will be at PS. Now the lines F PS and GPS are horizontal lines in perspective—that is, the perspective of the base gH (Fig. 115): therefore, where the visual rays from the points in the base cut the picture plane in ƒ (three lines close together) will give the points, k, l, m, whence the perpendiculars of the wall must be drawn, the lower slope Fn must be drawn between the lines e, g (see Fig. 115), and the perpendicular

William. Well, I understand that; but in our house everybody says "they does," and you told me yesterday that was

wrong.

Thomas. It is wrong; remember, I said that we are guided by the practice of educated Englishmen, and educated Englishmen say, 66 they do."

William. But what does the word grammar signify? I thought a grammar was a book; you say it is a science.

Thomas. It is both. Grammar is a word of Greek origin. It comes from a Greek word, ypapua (gram'-ma), which denotes a letter, a letter of the alphabet. Hence grammar is the science of letters letters, that is, employed to express ideas. Listen: letters represent sounds, and form syllables and words; words represent sounds; and the sounds they represent stand for thoughts or ideas; while those thoughts or states of mind represent things, objects in the inner world or in the outer world. This statement will require thought. Do not trouble yourself too much about it now; you will understand it by-andby. But observe that grammar is the science by which you learn to express your ideas correctly, that is, according to the usages of the best authors. And a book in which these usages are set forth as rules is also called a grammar. Every language has rules peculiar to itself. Hence we have " French grammar," "Greek grammar," as well as " English grammar."

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have admitted a line to s3, and consequently would I have cut the picture plane EE1at a higher point than g; and that point of intersection would have been shown below g in the reflection. And also for reasons given above, we see parts reflected which are not visible in the objects themselves. Figs. 117 and 118 will satisfy the mind upon this point.

The subject is a cottage on a bank with a large notice-board in front of it. The profile view (Fig. 117) will explain the distance of the board from the cottage, and this will account for the great difference between the details of the projection A and the reflection B in Fig. 118. If the pupil fail not to work out this problem also (of which, being constructed by the same rules as the former, we give no detailed PP explanation, but prefer leaving it as it is, for an exercise), he will more readily understand it, and the method of construction also; remembering that the visual rays drawn from every important point of the whole passing through P P (the picture plane) determine the points to be transferred to the corresponding plane on the left in Fig. 118. We remark that the notice board covers part of the roof in the projection A, whilst it is clear of the

roof in the reflection B. Also compare the chimneys in both cases with respect to their apparent position with the board. In the reflection n the sills of the windows are on a line with the base of the post, and the thresholds of the doors cannot because they are hidden by the bank. There are rencos, which the pupil will be able to discover

for himself. The same may be satisfactorily proved with regard to clouds. It is common, also, in their cases to see brilliant reflections of light clouds on the water, when to the eye there is nothing to account for them. These reflections are invariably caused by light clouds which are hidden from

view behind other clouds, the reflections affording us the only evidence of their existence. Why is this? And where is the root of the mistake that is so frequently made, that, without exception, whatever we paint above the water must be necessarily repeated by its reflection? It is simply this, that many treat the whole view, sky and all included, as one single plane, never thinking there are parts more reflected which

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remote than others, and consequently many are are shut out from the eye by intervening objects. Water not only receives reflections, but, conditionally, is capable of receiving shadows. If the water is perfectly clear, no shadows occur, and the reflections are more or less vivid in

proportion as the water is more or less impregnated with colouring matter, say clay, or as rivers generally appear after heavy rains. Then the strength of the reflections and shadows alternate in proportion to the clearness or opacity of the water. When it is very thick and muddy, the sha dows of objects are cast as forcibly upon the surface as they are on a road; and as it becomes clearer, the reflections become more bril liant and the shadows weaker: the earthy par ticles mingled with the water receive the shadow, not the water itself.

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In perfectly clear water the light passes through the water itself, as through a piece of glass, lighting up the bed of the river, so that we are able to distinguish readily the stones, weeds, fish, and whatever else may be at the bottom; then the shadow which falls upon the water sinks as it were, and is seen at the bottom only.

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