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THE WEDGE.

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equilibrium when the weights bear the same proportion to each cord upon it, we shall have a screw, the spiral line traced out other as the lengths of the inclines on which they rest: for by the cord being called its thread. It is easy to see that the it is clear that, the steeper the plane, the less is the portion of thread has at every point the same inclination as the inclined the resistance borne by it. If, for example, one incline is 15 plane, and that a particle in travelling up the screw will pass inches long, and the other 21 inches, a weight of 5 pounds over the same distance as if it moved up the plane. on the former will balance one of 7 pounds on the latter. A screw, then, is a cylinder with a spiral ridge raised upon it; For, supposing the vertical height of the summit to be 6 inches, this ridge is sometimes made with a the portion of the force of 5 pounds which acts downwards, and square edge (Fig. 79 a), and then has tends to raise the other, is is of 5 pounds, which equals 2 more strength; but usually it is pounds; while the portion of the other which acts downwards is sharp, as seen in a common screw, of 7 pounds, which is also equal to 2 pounds.

and this way of making it reduces This system of two inclines is often used in mining districts, friction. a train of loaded trucks running down from the pit's mouth to To use the screw, it is necessary the staith, being made to drag a train of empty ones up the to have a hollow cylinder with a incline. Many familiar instances of the use of the inclined groove cut on the inside of it (Fig. plane are met with every day, though they often escape notice, 79 b), so that the thread of the screw unless we are specially looking for them. Our knives, scissors, (Fig. 79 c) exactly fits into it, and the bradawls, chisels, needles, and nearly all cutting and piercing screw will rise or fall according to tools, act on this principle. Those immense blocks of stone which way it is turned. This hollow placed across the top of upright pillars, which excite the surprise cylinder is called the nut or female of all visitors to Stonehenge, are believed to have been raised in screw. this way, by making an inclined plane and pushing them up on It is evident that, if we are to gain mollers.

any power, the nut must not be al.

Fig. 79.

lowed to turn together with the screw; We pass on now to notice the wedge, which essentially con

and hence we have different modes of using the screw, according sists of two inclined planes of small inclination placed with as the screw itself or the nut is fixed. When used to fasten the their bases one against the other.

beams of a house together, or to strain the wire of a fence, the Sometimes one side only of the wedge is sloping, and it is screw is prevented from rotating, and the nut turned by a then simply a movable inclined plane. In using this, it is so

wrench; the screw is thus drawn forward, and the required placed that it can only be moved in the direction of the length, strain applied. In a carpenter's vice, on the other hand, the and the weight to be raised is likewise prevented from moving The gain is in each case just the same, the difference being

nut is fixed, and the pressure applied by turning the screw.
in any direction except vertically. If
P

pressure be applied to the head of the merely one of convenience in applying it.
wedge, the weight will be raised. The

Now we shall easily be able to see the amount of power gain is the same here as in the in. gained. If a particle be placed at the point of a screw and clined plane.

prevented from turning with it, it will, after one revolution of The wedge, however, usually con

the screw, have been raised through a distance equal to that sists of a triangular prism of steel, between two threads of the screw, while any point in the cir

or some very hard substance, and is cumference of the screw will have passed through a space equal с used as shown in Fig. 78. The point surface of the screw, it will bear the same proportion to the

to that circumference. If, then, the power be applied at the
is inserted into a crack or opening,
and the wedge is then driven, not by a resistance that the distance between two threads of the screw

constant pressure, but by a series of does to its circumference.
Fig. 78.
blows from a hammer, or some similar

In practice, however, the power is nearly always applied at instrument. It is usual to consider the extremity of a lever, as at d in Fig. 79 a, so that it becomes a the wedge as kept at rest by three forces—first, a pressure combination of the lever and inclined plane. In a thumb-screw scting on the head of the wedge, and

forcing it vertically down. the flattened part acts as a lever, and when a screw is driven by wards, as at P; secondly, the mutual resistance of it, and the

a screwdriver we usually grasp it at the broadest part, and obstacle which acts at right angles to the surface of the wedge, thus gain a leverage. More commonly, however, a long lever is acts at right angles to the direction in which the object would fundamental principle of virtual velocities. Hence, we have the as at RR; and thirdly, the force which opposes the motion, and put through the head of the screw.

In all such cases we can easily ascertain the gain from the move, as at c.

As, however, the resistance to be overcome varies very much following rule :-Measure the circumference of the circle defrom moment to moment, both in direction and intensity, and as

scribed by the power, and divide this the force is usually supplied by impact or blows, and not by by the distance between two threads pressure, such calculations afford very little help towards deters of the screw; the result will be the mining the real gain.

mechanical gain. The other mechanical powers are usually employed in sustain. whose circumference is 10 feet, and

Thus, if the power describe a circle ing or raising a weight, or offering a continuous resistance; a continuous force is therefore used with them. In the wedge, the distance between

two threads be the resistance to which it is applied is usually one which, when inch, we have a gain of 10 feet once overcome, is not again called into play. În splitting timber, divided by inch, or 480. . There is, for instance, when the wedge is driven in, the particles of timber however, a difficulty here. We canare forced apart, their cohesion is overcome, and they do not not easily measure the actual space join again. So in dividing large stones, when once a crack has through which the power passes, nor been made through them, no continued application of force is

can we calculate it with absolute needed to keep them from re-uniting. When continuous force is accuracy.

It is, however, usually required, the wedge having been driven forward is kept from near enough if we take the circumalipping back by friction.

ference as 34 times the diameter. As, then, we cannot calculate the force generated by a blow, but you may always use 34 without

The fraction is more exactly 3:14159,

Fig. 80. we must be content with the general statement that the smaller being far wrong. Thus, if the radius of a circle be 2 feet 6 the angle of the wedge the greater is the power gained.

inches, its diameter is 5 feet, and its circumference 34 times 5

feet, or about 15 feet 84 inches. We see then, now, how to This is the last of the mechanical powers, and, like the wedge, work a question like the following :-In the screw of a book. acts on the principle of the inclined plane. If we stretch a cord binder's press there are 3 threads to an inch, and a force of 10 30 a3 to represent the slope of an inclined plane, and then, hold-pounds is applied to a lever 14 inches long. What force are ing a raler, or some cylindrical body, vertically, we roll up the the books pressed with ? The gain is 14 x 2 x 34 divided

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B

THE SCREW.

by \, which equals 264; and as the power is 10 pounds, the 3. 2,700 pounds. pressure is 264 X 10, or 2,640 pounds. The real pressure is,

4. He must have a force of 16}pounds. The gain is

18x 60 x 54

6x8x41 however, less than this, as a portion of the power (sometimes 270,; and two tons divided by this give 1634 pound set down at a third) is employed in overcoming friction.

5. A little over 69 pounds. Still, this is not altogether lost, for it prevents the screw

6, I must pull with a force of 98 pounds through a space of 4 feet.

7. 155 pounds. The middle rope sustains 20 pounds of the weight. turning back when the pressure is removed. We have clearly

8. The front man will bear of the weight, or 931 pounds, the other two ways of increasing our gain in the screw, we can either 567 pounds. lengthen our lever or make our threads closer; but we soon reach a practical limit to either of these, as the lever becomes inconveniently long, or else the throads so narrow that they

LESSONS IN ENGLISH.-XVI. are stripped off by the pressure.

SUFFIXES (continued). To obviate this difficulty, an arrangement-known, after the inventor, as Hunter's screw—was planned. Fig. 80 represents THERE is nothing that will help more to form an English heart this. A hollow screw, A, of rather large diameter, is cut and made in ourselves and in others than the study of the English lan. to work through a strong fixed nut; another scrow, B, of smaller guage. We could scarcely receive a single lesson on the growth diameter is fixed to the upper board of the press, a female screw of our English tongue, we could scarcely follow up one of its being out in the interior of the first, into which this may work. significant words, without having unawares a lesson in English Supposing now that both screws have the same number of history as well; without not merely falling on some curious fact threads in a foot, the board will not move at all when the upper illustrative of our national life, but learning also how the great screw is turned, for the fixed screw will enter the hollow of it heart which is beating at the centre of that life was gradually exactly the same distance as it is depressed. But if the upper shaped and moulded. We should thus grow, too, in our feeling one has, say 24 threads in a foot, and the othe-: 25, the one will of connection with the past, of gratitude and reverence to it; we have moved downwards at of a foot while the other will have should estimate more truly, and therefore more highly, what it risen is only, and the board will be depressed by the difference has done for us, all that it has bequeathed us, all that it has between the two, which is auto of a foot. It is obvious that we made ready to our hands. It was something for the children may diminish as much as we like the difference between the two of Israel when they came into Canaan to enter upon the wells threads, without at all decreasing their strength, and the more which they digged mot, and vineyards which they had not nearly they are alike, the greater power we gain. The principle planted, fields which they had not sowed, and houses which they of this screw is very similar to that of the Chinese windlass, had not built; but how much greater a boon, how much more described in Lesson IX.

glorious a prerogative, for any one generation to enter upon the There is a modification of the screw, or rather a combination inheritance of a language which other generations by their

of it with the wheel and axle, truth and toil have made already a receptacle of choicest treawhich is frequently used. It sures, a storehouse of so much unconscious wisdom, a fit organ is known as

the endless for expressing the most subtle distinctions, the most tender screw, and is represented in sentiments, the largest thoughts, and the loftiest imaginations, Fig. 81. A thread is cut which at any time the heart of man can conceive.* upon an axle, which is turned Ery, erie; compare together coop (a barrel), cooper, coopery ; by a winch, and the teeth of brew, brewer, brewery; smite, smith, smithy; and you see that the wheel catch in the thread the terminations ery, ry, or y, denote a place where a certain of the screw and are thus trade, etc., is carried on. Similar is the force of the ending ary pressed forward as the winch and ory; as, aviary (Latin, avis, a bird), a bird-room; dormitory is turned, each revolution ad (Latin, dormio, I sleep), a sleeping-room; grapary, a place for vancing the wheel one tooth. grain. Comparo ary. Hence the winch must be “I can look at him (a national tiger) with an easy curiosity, as turned as many times as there a prisoner within bars, in the menagerie of the Tower."-Burke, “Regi

are teeth in the wheel in cide Peace." Fig. 81.

order to raise the weight a Menagerie comes from the French menage, which is the origin

distance equal to the circum- of our manage, and both are from the Latin manu, with the hanit, ference of the axle ; and since, in the ordinary wheel and axle, and ago, I drive, signifying to tame, to keep in order. the power is to the weight as the radius of the wheel is to that

Es or s is a suffix by which is formed the third person singular of the axle, so here, the gain is expressed by the length of the

or verbs, and the plural of nouns ; as, I read, he reads; ship, arm to which the power is applied, multiplied by the number ships ; box, boxes. When an apostrophe precedes the 8, as in of teeth in the wheel, and divided by the radius of the axle.

man's, the genitive case is intended.-.9., man's book; God's In all these cases it has been supposed that the screw has word. only one thread. Occasionally it has two, and then the gain is Esque, a termination derived from the Latin iscus, through only one-half.

the Italian esco, and the French esque, is found in grotesque and We must now give a few more examples for practice, and also picturesque. Grotesque means distorted, unnatural, and heterthe answers to those in our last lesson.

geneous; from the strange and extravagant figures which were EXAMPLES.

painted in the grottos or crypts of the ancient Romans. 1. An ascent is 120 yards long, and rises in this length 10 feet : what

“ An hideous figure of their foes they drew, power is required to sustain a weight of 7,236 pounds on it?

Nor lines, nor looks, por shades, nor colours true, 2. A road rises 1 foot in 25 : what strain is required to sustain a

And this grotesque design exposed to public view." wagon, weighing 1 ton, on the incline ?

Dryden. 3. A wedge is 11 inches long and 2 inches thick : what resistance will a pressure of 112 pounds on its head overcome ?

Picturesque is that which makes a picture, or may enter into & 4. A screw has four threads in the inch: what force must be applied

picture. to a lever 1 foot long to press with a force of 3,000 pounds ?

" Picturesque properly means what is done in the style and with the 5. The lever of a screw is 2 feet 6 inches long, and is moved with a spirit of a painter."—Stewart, “ Philosophical Essays." force of 6 pounds. Required the pressure, there being three threads to the inch.

Ess, derived from the Latin ix, the feminine of or; as adjator, 6. In Hunter's screw, if one have 10 and the other 11 threads in a a helper ; adjutrix, a female helper, converts masculine nouns foot, and the lever is 1 foot 9 inches long,'what is the gain ?

into feminino e.g., abbot, abbess; aotor, actress; prince, princess. 7. An endless screw is driven by a 12-inch crank. The axle is 2 Est, a verbal suffix, forming the second person singular of the inches in radius, and the wheel has 45 teeth. What weight will a present tense; as read, readest. It finds corresponding terminapower of 8 ounces sustain ?

tions in the s of the Latin, as legis, thou readest; and the stof ANSWERS TO QUESTIONS IN LESSON XI.

the Saxon, as børnst, thoni burnest. This suffis is rapidly be1. He must press with a force of 74 pounds.

coming obsolete, since the second person singular of the verb is 2, Six feet from the heavier boy, as there the moments about the fulcrum will be equal, for 6X72 = 8x54.

Trench “On the Study of Words," pp. 25, 26.

now rarely used; and in the cases in which it is chiefly used

“How oft, my slice of pocket store consumed, namely, by the poets, and by the Society of Friends—the est is

Still hungering, pennyless, and far from home, for the most part dropped. Indeed, but for its constant employ

I fed on scarlet hips and stony haws."-Cowper, “Task." ment in the public prayers of Christian churches, it would now Fy is from the Latin facio, I make. Facio, in combination, probably be wholly out of use. Nor would the language suffer becomes ficio, as in efficio. The fi in this word, written fy, is by its discontinuance; for, as the person is marked by the pro- the particle under consideration. It is seen in fructify, literally, noun thou, there is no occasion for any inflection of the verb, to make fruit ; that is, to make fruitful. and such inflection abates the euphony, and diminishes the “ Calling drunkenness, good-fellowship; pride, comeliness; rage, adaptability of our verbs.

valour; bribery, gratification."-Bishop Morton, Et, as in turret (Latin, turris, a tower), is a diminutive, a small

Head or hood, from the Saxon had, head, in composition, tower'; coming to us from the Italian torretta.

denotes the essence of any person or thing; its essential condi“Now like a maiden queen she will behold,

tion, viewed as a whole : thus, in Anglo-Saxon and English, From her high turrets, hourly suitors come;

manhad, manhood; wifhad, wifehood, or womanhood; cildhad, The east with incense, and the west with gold,

childhood ; brotherhad, brotherhood ; preosthad, priesthood. Will stand like suppliants to receive her doom."

Dryden.

Canst thou, by reason, more of godhead know,

Than Plutarch, Seneca, or Cicero ?" Eth, the old termination of the third person singular of the

Dryden, “ Religio Laici." present tense of the English verb; as eateth, found in part in Head is sometimes employed with a more direct reference to the the Latin legit, and found in full in the Anglo-Saxon bærneth, meaning which it has in current use; as in wronghead and he burneth.

wrongheaded, etc. "He that goeth forth and weepeth."-Ps. cxxvi. 6.

“Much do I suffer, much to keep in peace,

This jealous, waspish, wronghead, rhyming race."-Pope. Ette, of French origin, is found in words taken from the French ; as, coquette, etiquette. Coquette is, with us, applied to tain a wrongheaded distrust of England.”—Bishop Berkeley.

Whether we [the Irish] can propose to thrive so long as we entera female who employs her personal attractions to gain attention from males. In French there is the word coquet, a male coquette. After a similar manner we use both heart and head, in faintCoquet seems to come from coq, a cock, a showy and uxorious hearted, lighthearted, hotheaded, lightheaded. animal; and accordingly, it signifies a man who resembles a

Ible, see able, formerly explained under suffixes. cock in' his attention to woman. By a natural step in the pro- and the German ich, isch; as soporificus (Latin, sopor, sleepiness),

Ic, ick, ich, have counterparts in the Latin termination icus, gress of language, the term was applied to females.

soporific, rusticus (Latin, rus, the country), rustic, cildisc in Anglo-
" Coquet and coy at once her air,
Both studied, though both seem neglected;

Saxon, childish in English; bookish.
Careless she is with artful care,

“ The sweet showers of heaven that fell into the sea are turned into Affecting to seem unaffected."-Congreve.

its brackish taste."-Bates. Etiquette is the game word as our ticket, and originally denoted Ical, an adjective-ending, from the Latin icalis : for example, the short inscriptions, or tickets, put on packages of goods to amicalis, amical (friendly), grammaticalis, grammatical ; 80 point out what they contained. But similar etiquettes or tickets critical (Greek, spivw, pronounced kri'-no, I judge), which passes were employed to declare certain observances required in a into a noun by dropping al, as critic; so musical, music, mystical, public assembly; and so the word came to signify forms and mystic. formalities, a strict regard to custom ; and in general, social

Fool, thou didst not understand conventionalism, particularly in relation to deportment.

The mystic language of the eye nor hand.”-Donne. Eur, a French termination, from the Latin or: thus vendeur

Ie, from the Latin adjective termination ilis, to be seen in (a seller) is from the Latin venditor ; proditeur, a betrayer, from docilis (Latin, doceo, I teach), docile, teachable ; fragilis (Latin, the Latin proditor. It is similar to import to our ending er, and frango, I break), fragile, easily broken. Some Latin adjectives denotes an actor: for example, producteur, Fr. a producer. Of in ilis are represented by adjectives in ful in our tongue, as old many English words, now terminating in or, terminated in utilis, useful. eur; as autheur for author. The termination is still retained

In, ine is from the Latin termination inus, which denotes in certain nouns denoting abstract qualities : for instance, sometimes a name, as Tarentine, an inhabitant of Tarentum, grandeur (Latin, grandis, great); hauteur (French, haut, high), but in English more often a quality, as genuine, from the Latin derived immediately from the French. The notion of the actor genuinus, which is derived in its turn from genus, a kind or is retained in the French douceur (from the French doux, sweet), race—that is, that which possesses the qualities belonging to its a sweetener ; a fee, or bribe.

kind, in opposition to spurious, which, in its Latin meaning, Ever, connected in origin with the Latin ævum, age; and the signifies a bastard. Greek awv (i-own), age, comes to as directly from the Anglo

No foreign gums, nor essence fetched from far, Saxon ofre, and signifies always, an enduring reality, either in time past (Ps. Ixv. 6; xc. 2), time present (Ps. cxix. 98), or

No volatile spirits, nor compounds that are

Adulterate ; but at Nature's cheap expence time to come (Ps. cxi. 5). Ever, as a suffix, strengthens the

With far more genuine sweets refresh the sense."-Carero. word to which it is appended : thus, " whatever you do" has more force than “what you do.Ever is found in other com

Ing, in Anglo-Saxon, signifies son, as Edgar Atheling; that is, pounds; for example, whoever, however, wherever, whenever. Edgar the son of Athel

, or Edgar of noble blood. In English, ing Additional force is given by the insertion of the particle so; sing ; also a very large class of nouns ; thus, singing itself may

forms the ending of our active participles, as singing, from to 29 whosoever, whencesoever, whithersoever. This so used to stand where ever is now placed; as, whoso, howso, whatso.

be employed as a noun, as the singing was good.

These nouns,

as might be expected from the meaning of the Saxon ing, denote “ Her cursed tongue (full sharp and short)

existence; thus, to sing is a verb, but singing is the active of Appeared like aspis' sting, that closely kills,

the verb in actual being, When these words in ing are used as Or cruelly doth wound whomso she wills."

Sponser, "Faerie Quoono."

nouns they should have the government of nouns ; thus, the

singing of the birds was delightful. Almost every English verb Ful, of Saxon origin, obviously the same as the adjective may be made into a noun by the suffix ing; to eat, the eating; full, gives an instance of the origin of these particles in words to diminish, the diminishing; to run, the running. Obserye which originally had a definite form and signification. According that the idea of activity is connected with nouns ending in ing; to its root-meaning, full (now in combination written ful) denotes as, the seeing; the hearing; the dancing; the reporting-that a large portion of the quality indicated by the word to which it is, the act, the process of dancing, reporting, etc.—wherein those is affixed; as, hate, hateful ; thank, thankful; grateful, delightful. nouns differ from other nouns which express the result of an Full has for its opposite less ; for example, merciful, merciless. action; as sight, the result of the act of seeing; report, the In the employment of words, you cannot follow analogy alone, result of the act of reporting. The former have been called but must consult authority: thus, you may say penniless, but active, the latter class passive nouns, from the analogy they you cannot say penniful; yet pitiful is as good as pitiless. bear to active and passive verbs.

" We use

LESSONS IN DRAWING.—XVI.

will give additional character and truthfulness. It may not be FOREGROUNDS,HIGH LIGHTS–SETTING DRAWINGS, ETC. drawing, as probably their whole extent may not be seen; but

necessary that these stens should be completed in the finished In continuation of our remarks upon Foregrounds, we introduce the slight indication of their whereabouts may be useful for the in this lesson a group of dock-leaves. In the drawing, Fig. 108, purpose of adjusting the foliage according to the class of tree we have shown how the principles we endeavoured to explain in to be reprosented. This process is to be followed throughout the last lesson are to be carried out. The leaf in front repre- the whole drawing. This, which we will call the first stage, must sents in itself a summary of our observations. Notice the pro- be done faintly, so that, with india-rubber—or, what is better jecting part receiving the highest light; the dark cast shadow for the softer kinds of paper, bread-crumbs—these marks may underneath being the strongest in the drawing. Notice, also, the be weakened when the second stage is ready for commencement. cast shadow across the leaf (caused by the one on the left, which In this portion of the work there must be no indecision, par throws the under-leaf back, and brings out the one in light), ticulars must be entered into, especially those upon which the commencing strongly near the high light, and gradually becoming light falls. Amongst these will be found many that owe their

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lower in tone as it recedes ; this, together with the manner of | prominence to sharp, clear terminations ; and the distinctness drawing the carved lines on the surfaces of the leaves, tends to of their forms will be in proportion to the amount of light which give the perspective, and consequently assists in this way to falls upon them. The stems previously and slightly traced may determine

the size of the leaf. Examples of this kind can be now receive in those parts in sight all the forcible and distinctive 80 easily obtained from Nature, that we prefer to leave the pupil qualities they demand, even to the peculiarities observable upon to select them for himself, advising him to preserve them for the bark. At all times avoid a multiplicity of lines when one nse as we have recommended, and, when drawing from them, to only will be sufficient. When we see, as we frequently do in the allow his mind to recur to the previous remarks upon the prin early attempts of beginners, a number of lines of all lengths and ciples we have laid before him, which apply not only to the hicknesses muddled together, we can only attribute the practice drawing of a simple weed or dock-leaf, but have their never- to doubt and uncertainty; they are waiting to see the effect failing influence upon all subjects admissible in art. In the before they can make up their minds as to the one right line drawing of trees and the larger kinds of shrubs, we must urge required. Such a proceeding indicates

weakness, and creates the practice of being particularly careful of the outline, the first confusion. If we were to extend our instructions beyond the process of which must be confined to the general proportions single snbject of a tree, and include the whole

landscape generally

, and positions of the parts in light; and, at the same time, where we could only repeat what has been said before, as our remarks it is possible, trace by a faint line the course of the stems, which are equally applicable to distances and mountains, where it

would be a great mistake not to be especially careful in their with it cover down the whole of the part intended to be white; forms and outlines. These lines must not be strong, but firm when dry, proceed to the completion of the drawing. It will not and decisive, and the more simple the better; all darker lines in the least matter if the lead pencil should pass over the part must be reserved for the foreground. The method of securing gammed, it will not have any effect upon it. When the drawing the lights upon trees, which we have shown in Fig. 109, will is finished, pin it down at the corners on a board, let it be held explain to the pupil the manner of proceeding more clearly than in an inclined position, and pour some hot water over it; the gum words can do. In his practice we recommend him first to copy immediately dissolves, leaving the parts which were covered by parts of the example, and make separate and repeated studies it perfectly white. Broad spaces in light, opon which are to be of those portions which, as he proceeds, he will find to be most drawn minute and sharply-cut details, may be preserved in this

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difficult. He will be better able to decide for himself than we way, and, after the gum is washed off, the details may be made man for him as to which of those parts may require more frequent out upon them. This leads to the use of gum-water in another repetition; and it is almost needless to say, that by frequent way, and that is, as a means of fixing the drawing. If a drawing repetition only can he hope to succeed. There is a very easy is worth anything, it surely is worth setting, that is, fixing the and legitimate way of preserving in pencil drawings the sharp lead or chalk with which it is drawn, so that, under moderate touches of light which are seen upon polished surfaces, streaks treatment, it cannot injure by rubbing. For highly-finished in water, blades of grass, the bright parts of clouds, small objects drawings, or where the chalk or pencil has been very liberally of a naturally light colour on a dark background, or any effect applied, it will be better to proceed in this way :-Nearly fill a where brilliancy is requisite, and where à sharp, clear, and shallow dish or tray, somewhat larger than the drawing, with a listinct outline of the form must be preserved. It is this — weak solution of gum-water, or—which may sometimes be more After the outline of the object, or part to be preserved, has been convenient–a mixture of milk and water, half of each ; pass nade, dip a fine hair-pencil into tolerably strong gum-water, and the drawing carefully through the mixture (face uppermost)

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