which is a little water, the oxygen of the air in the jar partly becomes ozone.

This body is also formed when electric sparks pass between two points. The sulphurous smell in the neighbourhood of a strong electric machine, or of a flash of lightning, is the peculiar smell of ozone. Ozone is a very powerful oxidising agent. It can even separate the iodine from the compound potassium iodide-forming potash and liberating the iodine. This fact has been used as a test for ozone. Iodine makes a blue compound with starch, so that if a piece of paper be dipped in a mixture of starch paste and potassium iodide, if any ozone be present the paper becomes blue. This test alone, however, is not decisive, for nitric acid, which is sometimes found in the air, will do the same thing. It has been said that the health of a district depends upon the quantity of ozone in the atmospherebut this fact is not satisfactorily established. Since it is a great oxidiser it is a powerful bleacher, for by oxidising the colouring matter it destroys it. It is hoped to apply it to the bleaching of sugar, which has hitherto been effected by charred blood. A powerful magneto-electric machine has lately been sent out to the West Indies to produce ozone, wherewith to bleach sugar. Ozone was discovered by Professor Schönbein, of Basle, to whose genius we also owe gun-cotton.

LESSONS IN ENGLISH.-XVIII.
SUFFIXES (continued).

WORDS have been curiously formed by abbreviation; the word' omnibus affords an instance: derived from the Latin "omnibus," the dative case of the plural number of the Latin adjective omnis, all, and so signifying for all-that is, every man's carriage-the word has been shortened into bus, and so it is now generally termed in common parlance. Mob appears to have been formed in the same way. What is now called the mob used to be called the rabble. But as the rabble are mobile vulgus, a fickle crew, so were they called mobile vulgus, and by contraction, mob. Still mob and rabble are not identical. Rabble is the general term, the class, and mob is a collection of persons belonging to that class. Palsy is a contracted form of the now more fashionable paralysis. Between alms and eleemosynary there would seem to be no connection; both, however, come from the same Greek term, and the former is only a shortened form of the root from which the latter is derived. Well do we remember kickshaws, a term of our youthful days, used to signify something contemptible. Little did we then suspect that it was only the English way of pronouncing the French quelque chose; i.e., something, contemptuously travestied to mimic and ridicule French prisoners in England.

Kin, from the Anglo-Saxon cyn, kin, offspring, son, signifies the son of; as in Wilkin (Wilkins); seen in another formnamely, Wilson. Kin, from its signification, has also a diminutive force; as in lambkin (a lamb's child), or little lamb. What is little is dear, hence diminutives are terms of endearment. But what is little may be despised. Sometimes, therefore, diminutives imply contempt; as in manikin.

"This is a dear manikin to you, Sir Toby."- Shakespeare. Le (see el), among the suffixes already given.

Les, from the Anglo-Saxon læs (German, los, destitute of), has not a comparative but a negative force; as, an læs twentig, one less twenty, or, as we should say, twenty minus one. Hence it appears that the idea of less is privation or negation. Consequently less, the comparative of little, is altogether a different word. And thus we are also led to understand the true force of less when employed as a suffix; as, motionless, or without motion; deathless, free from death. Two negatives thus make a positive: death, the privation of life, and less, the negation of death, combine to declare the idea of ever-enduring existence, the most positive, the most real, the most permanent of all conceivable things, the very essence of Deity; life itself.

Let, according to Latham, "seems to be double, and to consist of the Gothic diminutive l, and the French diminutive t." It is found in streamlet, tartlet, hamlet (Anglo-Saxon, ham, home; as in hamstede, homestead).

Ling, of Saxon origin, denotes descent, and hence offspring; also that which is little, and that which is beloved; e.g., darling (dear child), gosling (little goose), nestling. Hireling is properly a child of hire, a person whose services are obtained by hire.

"The idea of contempt" ascribed to it by Latham does not necessarily, for it did not originally, belong to the word.

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

A tall, worthy stryplyng."-Skelton. The last line shows that nothing contemptuous belonged to the word in the olden time. Consult the ensuing :"Now a stripling cherub he appears,

Not of the prime, yet such as in his face

Youth smiled celestial."-Milton, "Paradise Lost." Ly, a termination of Saxon origin, having the force of our like, and so forming an adjective or an adverb; as childlike, childly, in German kindlich; manlike, manly, manlich. When ly is added to a noun, it forms an adjective, as love, lovely; when it is added to an adjective, it forms an adverb, as wise, wisely. Such a formation as "holily" (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, velo means I veil or cover; and velamen or velamentum is a veil or covering; so aliment (from the Latin alo, I nourish) is a means of nourishing, 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 loud

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 & 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 fol lowing 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 countinghouse 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 tho study easy to you. Once a week we will converse 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.

William. "Classics!" why, I thought the term "classics" was confined to the Greek and Roman authors, such as Homer and Virgil.

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.

wrong.

William. Well, I understand that; but in our house everybody says "they does," and you told me yesterday that was Thomas. It is wrong; remember, I said that we are guided by the practice of educated Englishmen, and educated Englishmen say, "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, ypaμua (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."

LESSONS IN DRAWING.—XVIII.

TREATMENT OF REFLECTIONS IN WATER.

Our

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. 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 edge, CD; s' being the position of the eye on the horizontal line. 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 AB equal to the length of the given wall, and draw the rectangle A G H B ; ABFE will represent the wall, EF HG the reflection. The pupil must be reminded that the line a cdb 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 a, 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

ko; the same with the upper slope. The reason why neither of these slopes are seen in the reflection is because the point P coincides with g (Fig. 115) on the picture plane: therefore the same line, F G, represents both extremities of the slope. If the slope B had had a greater elevation-that is, had it been at a greater angle

- then the upper extremity would

have admitted a line to s2, and consequently would 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 reaJons 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 B the sills of the windows are on a line with the base of the post, and the thresholds of the doors cannot be seen because they are hidden by the bank. There are other differences, 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

remote than others, and consequently many are reflected which 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

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.