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Near the mouths of great rivers, also, the sea has often a brownish hue, arising from the mud, and other earthy matters which are there held in suspension. The inquiry, therefore, "What is the colour of the sea?" must be kept quite clear of these accidental and local disturbances, and be confined to pure sea water.

Again:-The celestial blue tint of the sea is modified, and sometimes even totally changed in those places where the water is not very deep. The reason is, because the light reflected by the bottom reaches the eye mixed with the natural light of the water. The effect of this superposition may be calculated by the laws of optics; but we must join to our acquaintance with the nature of the two commingled tints, that, which is more difficult to ascertain,-their comparative intensities. Thus, a bottom of yellow sand reflecting but lightly, gives to the sea a green tint, because the yellow mingling with the blue produces green; now, if without changing the shades, the dull yellow is replaced with a bright yellow, the slight blue of pure water will scarcely suffice to make this a lively light green, and the sea will appear yellow. In the Bay of Loango the waters are always deep red; so much so, that they appear to be mixed with blood:-Captain Tuckey satisfied himself that the bottom is intensely red. If for this bright red bottom be substituted one of the same shade, but obscure and reflecting but slightly, the waters of the Bay would then appear orange-coloured, or even perhaps yellow. But it may be objected to this method of regarding the subject, that a bottom of white sand ought not to alter the hue of the sea, because, if white weakens the colours with which it mingles, it does not change the tint. In answer to this, it may be asked, how can we be certain that the sand at the bottom is white? We cannot be certain of this in the open day, after having brought up a portion and exposed it to the white light of the sun, or of the clouds; because the sand may not be in the same condition when beneath the water. If in the open air it be illuminated with red, green, or blue light, it would then appear red, green, or blue. What is the colour then that falls upon it at the bottom of the water? Water is in the condition of many other bodies which are known to possess two kinds of colours,-viz., a certain colour which is transmitted, and another colour quite different from the first, which is reflected. Water appears of a blue colour by reflection; and some imagine it to be of a green colour by transmission. Thus a portion of the white light which went to illuminate the water is dispersed by the water in all directions, after having received a blue tint therefrom; and it is this dispersed light which constitutes the proper colour of liquids. As to the other rays irregularly transmitted, their passage across the water makes them green, and intensely so in proportion as the traversed mass is thick. Now with regard to the white sand at the bottom of a sea not very deep, this sand receives the light only through a stratum of water; the light then is green when it strikes the bottom, and it is with this tint it is reflected; and in the second passage which the luminous rays make through the same liquid in returning from the sand to the open air their green tint sometimes so predominates, that it prevails over the blue. This, perhaps, may be the whole secret, which, to the seaman, is, in calms, the certain and invaluable index of great depths. But when the ocean is agitated, the waves suitably elevated may convey to the eye so large a quantity of transmitted or green rays, that the reflected blue ones shall be entirely concealed. The elevated waves of the ocean form a kind of prism; no wave is ever solitary; the continuous waves advance nearly in parallel directions. When two waves, therefore, approach a vessel, a portion of the light which the anterior face of the second wave reflects, traverses the first, is there refracted from above downwards, and thus arrives at the observer placed upon the deck. Again, then, we see transmitted

light, light which is consequently made green, reach the eye at the same time with the common blue tints; but these are the phenomena of great depths over white sand produced without deep water, and the green colour of the sea arises from the predominance of the transmitted colour over the reflected colour.

Some circumstances, however, will doubtless be observed which prevent these prism waves from always producing the same effects. Some variation in the line of the sea may be expected upon a change of the wind. Upon the lakes of Switzerland, this phenomenon is apparent; it remains to be seen whether it is so upon the wide ocean.

It has long been imagined that the blue colour of the sky has had an important influence on the colour of the ocean. It must be remembered, however, that the blue rays of the atmosphere do not return from the water to the eye, till after they have been regularly reflected.

An apparently dark coloured sea (says Professor Jameson,) is a common prognostic of an approaching storm; not that the water is really blacker than usual, but because the dark colour of the clouds indistinctly seen in, or reflected from, the waves, is mistaken for the colour of the sea itself. Whatever other colour the sky happens to wear has a greater or less influence on the appearance of the ocean; thus, red clouds seem to tinge it red, &c. On some occasions the edges of the waves, by refracting the solar beams like a prism, exhibit all the brilliant colours of the rainbow, which is still more nearly imitated by the refraction of the rays in the spray. Not unfrequently an indistinct image of the neighbouring coast, reflected from the ruffled surface, is

mistaken for the colour of the water.

With the intention of being freed as much as possible, from the influence of reflection, when studying the colours of the ocean, some able navigators have recommended the plan of examining it through the trunk of the ship's rudder. By this method the water exhibits in some points of view beautiful violet tints; but these hues are illusory; they are only the effect of contrast; they proceed from atmospheric light feebly reflected in an almost perpendicular direction, and coloured by their approximation to the transmitted green colours which almost invariably surround the rudder.

All attempts to investigate the colour of water must be begun when it is seen by transmission, with the aid of diffused light. Those who will recal to recollection the pre-eminently green hue of the cut edge of a crystal glass, even when this glass is only illuminated in front and perpendicularly, will perceive all the importance of this remark. The observer should be supplied with a large hollow ice prism: the refracting angle equal to 45°. This prism is to be plunged partially into water, to that the edge of its refracting angle shall be downwards and horizontal; one of the faces of this angle, viz., that which is most exposed, is to be vertical, whence it will result as a necessary consequence that the other face will be inclined to the horizon at an angle of 45°.

When the objects are thus arranged, the light which moves horizontally in the water at a fraction of an inch below the surface, that which constitutes the colour of its cutting edge, so to speak, will strike perpendicularly the vertical ice of the prism; it will penetrate into the interior of the instrument, will traverse the small quantity of air which it encloses, will reach the second plate of ice, and will there be reflected vertically from below upwards. In looking upon this inclined ice, the observer then may judge of the proper colour which the water has by refraction, quite as well as if his eye was in the liquid. In this form the experiment is simple and easy, and it is hoped that numerous observations will be made not only with sea water, but also with that of lakes and rivers.

It is desirable that the hollow prism be enclosed at its upper part by a piece of ice enclosed in glass, and having parallel faces. This will prevent the apparatus from being filled with liquid.

THE GREAT-HEADED TODY.

WE have lately noticed some of those beautiful and useful little birds common to tropical countries, and known under the general name of Fly-catchers*. We shall now briefly remark on a small group of birds, sometimes confounded with the fly-catchers and fly-hunters, but really distinct from both.

These are the Todies (Todus), small American birds confined to the warmer portions of the new world, and holding a similar place among the feathered tribes of the west, to that which the king-fisher holds among the birds of our own land. The most universal character by which these birds may be distinguished is, their flat, elongated bill, the sides of which are bristled, though these bristles are short and weak, and in some of the species scarcely discernible. The wings and tail are short, and the form in which they terminate marks the difference between the several species. The structure of the feet is subject to much variation. There are three toes to the front, and one to the rear; the inner front toe is united to the middle one as far as the second joint, and the external as far as the third. These birds nestle on the ground near the water, after the manner of king-fishers. According to Vieillot the female makes her nest in dry earth, but prefers soft friable sandstone. She makes choice, for this purpose, of ravines and small crevices, and digs with her bill and claws, forming a rounded hole, widened at the extremity, where she places leaves, moss, and cotton, with considerable skill. The eggs are four or five in number, of a grey colour spotted with brown. The female bird sits with great constancy, and the male is assiduous in supplying her wants. Both show great attachment to their young when they appear. The male bird is said by some writers to have an agreeable song at the pairing time; but by others this is denied. In general these birds are remarkable for their silence. They are pretty birds, feeding on insects, and perfectly inoffensive. Though their wings are short, their flight is rapid and straight-forward. They perch sometimes in trees and bushes, and sometimes on stones and

elevated spots of earth; but their colour is so much like that of the foliage of trees that they are seen only in the latter situations. Though not very rare, they usually dwell in wild and solitary places, which is probably the reason of their being by no means frequent in the collections of Europe.

The most commonly described species is the green tody, which is certainly the most beautiful of the group, as our account of it will presently show: but we have chosen for the subject of our illustration the great-headed tody described by Swainson, nearly in the following

terms:

The general plumage of the great-headed tody above is olive green, with a strong fawn-coloured tinge in front of the head and on the crown. This colour is separated

* See Saturday Magazine, Vol. XXI., p. 161.

from the back by the upper neck, being entirely of the same ash-colour as the sides, chin, and throat; but these two latter parts are striped with white; the rest of the under-plumage is yellow, tinged with olive, and striped with ash-colour on the breast and flanks. The sides of the head and base of the ear-feathers are whitish; the latter being ornamented with a broad black band; the wings and tail are brown, the feathers margined with yellowish; the tail-feathers even, but remarkably narrow, with their tips more pointed than in any of the other todies.

The most beautiful of all the todies, and of the whole of this family, as we have said, is the green tody. It is remarkable for the richness of its colouring, and Swainson remarks that its natural history, differing as it does in colour from all its congeners, must possess great peculiarities, but unfortunately we know but little of its habits and economy. It is said, that in resting it always sits with the head and bill pointing upwards, and it is thought that the bright red spot on its throat, acts, in such circumstances, as a snare to attract insects (just as a candle attracts moths), and they only discover their danger when it is too late to escape the sudden dart of the bird. This species inhabits some of the West India Islands, and is known in many of the equatorial regions of South America. The predominant colour of the upper parts of the bird is a rich parrot-green. The under plumage is more varied, the whole extent of the skin being occupied with a patch of the richest scarlet, bordered by a stripe of white, while the side feathers of the breast are of a delicate rose-colour, and the under part of the tail yellow. The total length is three inches and three-quarters. This beautiful little bird is called, by the natives of St. Domingo, the ground-parrot, or parakeet, from its habit of being almost always on the ground. It catches insects with much address, like the fly-catchers, though its habits, with regard to its nestingplace, resemble the king-fisher.

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The black-headed tody is rather smaller than the green tody, especially in the head. The upper plumage very dark ash-colour, with a few shades of olive. The head, wing-covers, and tail, are black,-all the under parts are yellow. This species inhabits Brazil and Cayenne.

Respecting the food of the todies in general, we have the assertion of Lesson, that it consists of insects which they catch in the mud or in the water. Their wide and flattened bill, he observes, furnished with bristles, permits them to sift the mud and retain their prey: they also seek for insects under the moss, and on the banks of small streams. Sloane, speaking of the green tody, says, it is one of the most beautiful birds of its size that he ever beheld. "It loves," he adds, "melancholy places, and scarce will stir from any one till they take it." Brown also speaks of it as a very familiar and beautiful bird, which will allow a person to approach within a few feet of it, and look for minutes together at it before it moves. He does not agree with some of our other authorities with respect to its retired habits, but says:"It keeps much about houses in country parts, flies very slowly, and probably may be easily tamed."

WHERE IS WISDOM TO BE FOUND? WHERE the eye of Pity weeps, And the sway of Passion sleeps, Where the lamp of Faith is burning, And the ray of Hope returning, Where the "still small voice" within Whispers not of wrath or sin, Resting with the righteous deadBeaming o'er the drooping headComforting the lowly mind,

Wisdom dwelleth-seek, and find!

LONDON:-JOHN W. PARKER, PUBLISHER, WEST STRAND.

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In the year 1841, a committee was appointed by the House of Commons to inquire into and report upon the state and prospects of the English school of Painting, the chief object being to determine upon a plan whereby the architect and the artist might work in conjunction with each other for the decoration of the new Houses of Parliament. In the report of the committee the employment of fresco painting was recommended; but the necessity of further inquiry on the subject was suggested. This led to the appointment of a royal commission of Fine Arts, the members of which in the spring of 1842 presented their report to Her Majesty, in which they

An appendix is added to this report, by Mr. Eastlake, in which is collected much valuable information on the subject of fresco painting. VOL. XXII.

stated their inability to satisfy themselves that the art of fresco painting had hitherto been sufficiently cultivated in this country to justify them in at once recommending that it should be employed in the decoration of the new Houses of Parliament; but in order to assist them in forming a judgment on this matter, it was proposed that artists should be invited to enter A public announceinto a competition in cartoons. ment was accordingly made, inviting British artists to compete for certain pecuniary prizes, by submitting cartoons to the notice of judges to be appointed to decide on the relative merit of the works. It was stipulated that the drawings should be executed in chalk, or in charcoal, or some similar material, but without

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colours; the sudjects to be selected from British History, or from the works of Spenser, Shakspere, or Milton; and the figures to be not less than the size of life.

Although the subjects for the exercise of the artist's skill were thus, to a certain extent, defined, it was expressly stated by the commissioners that such limitation was not meant to imply the adoption of any particular scheme for the decoration of the Houses of Parliament. The object in fact was to encourage among artists that which is so indispensable in fresco painting, namely, "precision of drawing, founded on a knowledge of the structure of the human figure; a treatment of drapery uniting the imitation of nature with a reference to form, action, and composition, and a style of composition less dependent on chiaroscuro than on effective arrangement."

As the time is now arrived for the exhibition of these cartoons to the public (Westminster Hall being the place destined for their reception), it may be interesting to give a popular notice of fresco painting; an art, which it is hoped is now about to be introduced into this country under the most favourable circumstances of patronage.

Respecting the origin of the term fresco there are two opinions: according to some the term is said to have been adopted because the practice of it is used in the open air. Thus in the Italian language, andare al fresco signifies "to take the air;" or "to walk abroad in the air;" but a more probable explanation is to be found in another meaning of the word fresco, viz., "new," or "fresh," as applied to the state of the plaster in which it is wrought. The artist traces his design, colours it, and completely finishes in one day so much of his picture as will occupy the wet plaster ground that has been prepared for him, so that when the ground is dry he may not retouch any part of his work. This is the characteristic distinction of painting in fresco-a method by which the painting is incorporated with the mortar, and drying along with it becomes extremely durable, and brightens in its tones and colours as it

dries.

It will therefore be readily conceived that the artist in fresco has to encounter difficulties of no ordinary kind; a few of them are thus noticed by a writer in REES'S Cyclopædia:

From the necessity there is in the progress of this style of art, that it should be executed with rapidity, and from the impossibility of retouching it without injuring the purity of the work; the artist, unless he be endowed with very extraordinary powers of imagination and execution indeed, is obliged to prepare a finished sketch of the subject, wrought to its proper hue and tone of colour, and so well digested, that there may be no necessity for making any essential alterations in the design. This, which is a very useful mode of proceeding in all fine works of painting, is absolutely indispensable in fresco, to those who are not determined to give the rein to their ideas, and leave as perfect whatever may first present itself. There is no beginning in this, by drawing in the whole of the parts at one time, and correcting them at leisure, as is the custom with oil-painters, who may therefore proceed to work without a sketch; here all that is begun in the morning must be completed in the evening; and that almost without cessation of labour, while the plaster is wet; and not only completed in form, but also, a difficult, nay almost impossible task, without a well prepared sketch, must be performed, viz., the part done in this short time must have so perfect an accordance with what follows, or has preceded, of the work, that when the whole is finished, it may appear as if it had been executed at once, or in the usual mode, with sufficient time to harmonize the various forms and tones of colour. Instead of proceeding by slow degrees to illuminate the objects, and increase the vividness of the colours, in a manner somewhat similar to the progress of nature in the rising day, till at last it shines with all its intended effect, which is the course of painting in oil, the artist working in fresco must at once rush into broad day ligat, at once give all the force in lignt, and shade, and colour, which the nature of his subject requires, and this without the assistance (at least in the commencement) of

contrast to regulate his eye; so that here, as has been said, a well digested and finished sketch seems indispensably requisite.

The custom of decorating walls with paintings is very ancient. Those discovered by Belzoni, among the royal tombs of Egypt, prove the existence of the art among the Egyptians many centuries before the Christian era. There is also abundant evidence that it was practised by the Etruscans and Romans. But the more common practice up to the time of Augustus seems to have been to paint the walls of houses of one single colour, and to relieve this with fantastic ornaments. According to Pliny, Augustus was the first to suggest the covering of whole walls with pictures and landscapes. About the same time a painter named Ludius invented that style of decoration, now called arabesque or grotesque, many beautiful examples of which have been discovered at Pompeii and other places. The invention of the Arabesque style, as its name implies, has been improperly claimed for the Arabians of Spain; whose religion forbidding the representation of animals, they employed foliage, stalks, stems, tendrils, flowers, and fruit, in a variety of forms and combinations, with which they adorned the surfaces of their buildings. Hence the fanciful combinations of natural objects occupying a flat surface came to be called Arabesque, although it differed so much from the Mohammedan compositions as to contain animals real or fabulous. That the term is badly chosen, especially as applied to the fanciful enrichments on the walls of Pompeii, &c., will be seen from the fact that such ornaments were invented and executed long before the sons of Ishmael had learned to draw. The term grotesque is less objectionable: it is derived from the subterranean rooms (grotte) in the baths of Rome, in which those specimens of ancient art were found, from which Raphael derived the plan of the beautiful frescos which adorn the piers and pilasters of the arcaded gallery of the palace of the Vatican, called, in honour of the artist, "Le Logge di Raffaelle."

The practice of Fresco Painting may be conveniently considered under the following heads:-1. The Cartoon. 2. The preparation of the wall. 3. The process of painting. 4. The colours and implements. The methods as adopted by different artists are of course subject to variation; but as general principles are not altered by variations in those details which conduce to the same end, so the following may be taken as an accurate exposition of the practice of the art.

1. The Cartoon. Since the artist cannot without

injury retouch a fresco painting, it is necessary that every part of the design be decided on by preparatory sketches finished of the full size, from which the fresco may be transferred, by tracing, to the wall. When the painting is very large, the whole composition of the full size is sometimes divided into two or more cartoons. In the preparation of a cartoon, a strong cloth is stretched on a frame, as if to be prepared for painting ; When this is paper is then firmly glued on the cloth. dry, a second layer of paper is attached by glue. The edges of the separate sheets, where they overlap, are scraped, so as to preserve an even surface. surface is then prepared for drawing with size and

alum*.

The

finished is fixed by wetting the cloth at the back with The drawing is made with charcoal, and when cold water, and then steaming the drawing in front. The steaming is performed with a tea-kettle with two or three spouts, kept boiling by the flame of a spirit-lamp; by this means the charcoal is incorporated with the melted glue, and a solid surface like that of a picture is produced.

oiled paper. As much of this working outline as can From this finished drawing the outline is traced on

The term Cartoon is derived from carione, the augmentative of carta, the Italian for paper.

be finished in one painting is then nailed to the wet wall, and the forms are again traced with a sharp point, whereby an indented outline is produced on the soft plaster. According to another method, the paper to be applied to the wall is placed behind and in close contact with the finished cartoon; the outlines of the latter are then pricked, and a similar pricked outline is thus produced on the paper behind. This pricked paper is then made the working drawing; it is fastened to the wall, and dusted with a little bag filled with black or red dust; this leaves a dotted outline on the wall. This method is sometimes adopted for small works, and the advantage of it is that it leaves the surface of the plaster undisturbed. The first mode is, however, generally preferred; since it insures the best and most decided outline, and preserves the finished cartoon uninjured.

Cartoons prepared for fresco may be seen in the National Gallery: those at the head of the staircase are by Agostino Caracci. In one of these (the Triumph of Galatea) the pricked outline is very apparent; as also in the fragment of the Cartoon by Raphael, (the Murder of the Innocents) also in the National Gallery. many celebrated Italian frescos the indented outline, produced by tracing, is apparent.

In

In addition to the cartoon it is desirable to have a coloured sketch of the whole composition.

2. The preparation of the Wall. The greatest obstacle to the permanence of fresco painting is damp: hence, if the wall to be painted is covered with old mortar, the ingredients of which are unknown, this coat should be entirely removed until the solid brick or stone is laid bare. The rough coat then applied is composed of river-sand and lime, and of such thickness as is generally used in preparing the walls of dwelling-houses. The surface of this coat should be rough, but not uneven. Thus prepared, the wall should be suffered to become perfectly dry and hard; the longer it remains in this. state the safer it will be, especially if the lime used was in the first instance fresh. In that case two or three years should elapse before the process of painting is commenced.

EASY LESSONS ON REASONING.
LESSON XI.

§ 1. AN Argument [or Act of Reasoning expressed in words] is defined "an Expression in which, from something laid down [assumed as true] something else is concluded to be true, as following necessarily [resulting] from the other." That which follows from the other, is called (as was formerly explained) the "Conclusion;" and that from which it follows, the "Premises;” or in the language of some writers, the "Antecedent." The above is the strict technical definition. But in ordinary language the word "Argument" is often employed to denote the Premises alone; or, sometimes that one of the Premises which is expressed, when the other is understood: as when one speaks of proving so and so by this or that argument; meaning, by such and such a Premise.

Premises, the Major (formerly explained) is, in common And you may observe, by the way, that of the two discourse often called the "Principle," and the Minorpremise, the "Reason."

Frequently also in common discourse "an Argument" is used to signify a " Series of arguments," leading ultimately to the Conclusion maintained.

An Argument if stated in such a regular form that "its conclusiveness [its being really an Argument] is apparent from the mere form of expression alone," (independently of the meaning of the words) is then called a "Syllogism." As, "Every X is Y*; Ź is X, therefore Z is Y:" in which, as was formerly explained, the truth must be admitted, whatever Terms you may make X, of the Conclusion,-assuming the Premises to be true,— Y, and Z, respectively, stand for.

You are to remember therefore that a Syllogism is not (as some have imagined) a peculiar kind of Argument; but only a certain form in which every Argument may be exhibited.

§ 2. One circumstance which has tended to mislead persons as to this point, is, that in a Syllogism we see the Conclusion following certainly [or necessarily] from the Premises; and again, in any apparent-syllogism which on examination is found to be (as you have seen in some of the examples) not a real one [not "valid"] the Conclusion does not follow at all; and the whole is a mere deception. And yet we often hear of Arguments which have some weight, and yet are not quite decisive; -of Conclusions which are rendered probable, but not absolutely certain &c. And hence some are apt to imagine that the conclusiveness of an Argument admits of degrees; and that sometimes a conclusion may, proyears before it is used, either for the purposes of paint-bably and partially,-tho' not certainly and completelying (lime being the white pigment) or for coating the walls.

The preparation and seasoning of the lime is one of the essential conditions of fresco painting. At Munich it is made and kept as follows:-A pit is filled with clean burnt limestone which is slaked, and then stirred continually till it is reduced to an impalpable consistence. The surface having settled to a level, clean river-sand is spread over it to the depth of a foot or more, so as to exclude the air, and, lastly, the whole is covered with carth. It is allowed to remain thus for at least three

The last preparation for painting on the mortar is as follows:-The surface is wetted with pure water, till it ceases to absorb. A thin coat of plaster is then spread over that portion only which is to be painted: the surface of this coat should be moderately rough. As soon as it begins to set (i.e. in about ten minutes or so, according to the temperature) a second thin coat is laid on, somewhat fatter, that is, with more lime and less sand. The plaster is laid on, and the surfaces are smoothed with a wooden trowel. Some painters like to work on a perfectly smooth surface, in which case the last coat is polished by applying a piece of paper on the surface and passing the trowel over it. When a small amount of roughness is required, a dry brush, or a piece of beaver nap attached to the trowel, is passed over the plaster in all directions.

As you brew, you must bake.

He who brews unskilfully, will have bad yeast; and bad yeast will make bad bread. The ill consequences of one imprudent step will be felt in many an after step.

follow from its Premises.

This mistake arises from men's forgetting that the Premises themselves will very often be doubtful; and then, the Conclusion also will be doubtful.

As was shewn formerly, one or both of the Premises of a perfectly valid Syllogism may be utterly false and absurd and then, the Conclusion, tho' inevitably following from them, may be either true or false, we can

:

not tell which. And if one or both of the Premises be

merely probable, we can infer from them only a probable conclusion; tho' the conclusiveness, that is, the connexion between the Premises and the Conclusion-is perfectly certain.

For instance, assuming that "every month has 30 days" (which is palpably false) then, from the minor-premise that "April is a month," it follows (which happens to be true) that " April has 30 days:" and from the minorpremise that "February is a month" it follows that "February has 30 days;" which is false. In each case the conclusiveness of the Argument is the same; but in every case, when we have ascertained the falsity of one of the Premises, we know nothing (as far as that argu

See above. Lesson ix. § 4.

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