An Ellustrated Glossary of Technical The following is a list of those most commonly COLOURS (in oil and water painting, &c.)

Terms used in Architectural and

Interior Decoration.

(Continued from page 121.)

CALIGULA (Caius),* a Roman emperor, lived

in use:

Ultramarine.

Observations Addressed to Young Painters.Of the above, all those various tints which are! required in painting are formed; but it is advisable to restrict yourself at first as much as possible to the use of the primary colours; and not until increased experience and power have CAMMILLUS, a protector of Rome, lived admixture." Colours in the works of art, been attained, venture beyond a very limited

A.R. 776, A.D. 36.

A.M. 3690, A.R. 390.

CATALINE (Lucius), a Roman

lived A.M. 3930, A.R. 638.

emperor,

says Mr. Hay, are regulated, in their arrangement, by laws founded on natural principles. There are, no doubt, many varieties of tastes in regard to colours, both individually and arranged. Many have fancies for, and antipathies to, particular hues. All have their tastes in regard to particular styles of colouring, some being fond of the gay and lively, some of the rich and powerful, and others of the deep and grave. Some have a partiality for complex arrangements, while others prefer extreme simplicity. It does not signify under what circumstances a variety of colours may be presented to the eye-if they be harmoniously arranged, the effect will be as agreeable to that organ as harmonious music to the ear." The principles upon which this simplicity and harmony are founded must be sought for in all-instructive Nature. It is most strikingly apparent in the colours of the rainbow, and in what may, with no great impropriety, be termed the artificial rainbow, formed by passing light through a glass prism. Correctly speaking, black is not a colour, but the absence of all colour, though there are few blacks which are not more or less tinged with blue, brown, or some other tint. White again is the union of the three primitive colours, in

CATO THE CENSOR, a Roman protector, lived the proportion of three yellow, five red, and

In

eight blue; but in other proportions white, like black, is tinged with various tints. common language both white and black are called colours. Of the three primary colours, yellow partakes most of the nature of white, being the lightest of all decided colours. Its contrast colour is purple, a compound of the other two primaries. It constitutes, in combination with red, the secondary orange; and when compounded with blue, it produces the secondary green. These two colours are, therefore, its melodising hues; and its most powerful contrast is black. Red, the second * A few words of explanation may be deemed necessary of the primaries, is the most positive of all respecting our reason for inserting these portraits. In colours, holding the middle station between designing vases, prize cups, &c., subjects are often taken yellow, which is most allied to light, and blue from Roman history, &c., wherewith to decorate them; and which is most allied to shade. The hues with in those cases, accurate portraits of the characters are of essential service. It is from this reason that we have adopted which it melodises in series are orange and the plan which we have this week commenced.-EDITOR. purple, being its combinations with the two No. 40. Vol. II.

A.M. 3905, A.R. 605.

other primaries. Its contrasting colour is lected in bamboos, taken to their houses, and green, a compound of yellow and blue. Blue boiled in order to drive off the watery particles. is the third of the primary colours, and and inspissate it to the consistence it finally asnearest in relation to shade or coolness. Its sumes. Although the process of boiling apcontrasting colour is the secondary orange, and pears necessary where the gutta is collected in its melodising colours in series, green and pur- large quantities, if a tree be freshly wounded, ple. Each of the intermediate compound co- a small quantity allowed to ooze out, and it be lours, or secondaries have others, with which collected and moulded in the hand, it will conthey are contrasted or harmonise, through every solidate perfectly in a few minutes, and have variety of tint. In order to obtain a know- all the appearance of the prepared article. ledge of the harmony of every colour appli- When it is quite pure, the colour is of a graycable to the practice of painting, the student ish-white; but, as brought to the markets of must assiduously investigate the numerous Australia, it is more ordinarily found of a redcombinations observable in nature, and per-dish hue, arising from chips of bark that fall severingly endeavour to re-produce these into the sap in the act of making the incisions, artificially. It is, however, satisfactory to and which yield their colour to it. Besides know that their most pleasing combinations are these accidental chips, there is a great deal of strictly regulated by the laws of harmony intentional adulteration by sawdust and other through the countless varieties of colour, from materials. Some specimens that have been their brightest or deepest tone to their tenderest obtained were found to possess very little tint. While the student, therefore, is investi- short of one-fourth of impurities; and even: gating effects observed in nature, he ought to the purest specimens yield, on being cleansed, make constant reference to these laws to direct one ounce of impurities per pound. Fortuhis inquiries. The practical part of painting nately it is neither difficult to detect nor clear consists in laying colours on the objects of the gutta of foreign matter; it being only a picture, so as to exhibit them under the necessary to boil it in water until well softened, peculiar circumstances in which they are roll out the substance into thin sheets, and pick placed with respect to the coolness or glow of out all impurities; which is easily done, as the the atmosphere, or the light, shade, or reflec- gntta does not adhere to anything; and all tion which may be thrown upon them. The foreign matter is merely entangled in its fibres, use of colours, accordingly, is the blending not incorporated in its substance. Mr. Oxley and adapting of them so as to impart to every has calculated that the quantity exported from object in a picture a natural appearance, and Singapore to Great Britain and the Continent, by a general harmony of the tints to produce a from the 1st of January, 1845, to the present pleasing effect upon the spectator. date, amounts to about 7,000 piculs; and that to obtain this quantity nearly 70,000 trees have been sacrificed!

(To be continued.)

Gutta Percha.

ALTHOUGH the trees yielding gutta percha abound in the indigenous forests of Australia, it is scarcely five years since it was discovered by Europeans. The first notice taken of it appears to have been by Dr. Wm. Montgomerie, in a letter to the Bengal Medical Board, in the beginning of 1843, wherein he commends the substance as likely to prove useful to some surgical purposes, and supposes it to belong to the fig tribe. In April, 1843, the substance was brought to Europe by Dr. D'Almeida, who presented it to the Royal Society of Arts, London, but it did not at first attract much attention.

The gutta percha tree, or gutta tùbau, as it ought more properly to be called,-the percha producing a spurious article-belongs to the natural family Sapotec, but differs so much from all described genera, that the naturalists of Australia are inclined to rank it as a new genus. The tree is of large size, from sixty to seventy feet in height, and from two to three feet in diameter.

The mode in which the natives obtain the gutta is by cutting down the trees of full growth, and wringing the bark at distances of about twelve to eighteen inches apart, and placing a coca-nut shell, spathe of a palm, or such like receptacle, under the fallen trunk to receive the milky sap that immediately exudes upon every fresh incision. This sap is col

When fresh and pure, the gutta is of a greasy feel, with a peculiarly leathery smell. It is not affected by boiling alcohol, but dissolves readily in boiling spirits of turpentine; also in naptha and coal-tar. A good cement for luting bottles and other purposes, is formed by boiling together equal parts of gutta, coal-tar, and resin. When required for use, it can always be made plastic by putting the pot containing it over the fire for a few minutes. The gutta itself is very inflammable, a strip cut off takes light and burns with a light flame, emitting sparks and dropping a black residuum in the manner of sealing-wax; which, in its combustion, it very much resembles.

But the great peculiarity of this substance, and that which makes it so eminently useful for many purposes, is the effect of boilingwater upon it. When immersed for a few minutes in water above 150 deg. of Fah., it becomes soft and plastic, so as to be capable of being moulded to any required shape or form, which it retains upon cooling. If a strip of it be cut off and plunged into boiling water, it contracts in size both in length and breadth. It is this plasticity, when plunged in boiling water, that has allowed of its being applied to so many useful purposes, and which first induced some Malays to fabricate it into whips, which were taken into some of the towns in Australia, and led to its farther notice. The natives soon extended their manufactures to buckets, basins, and jugs; shoes, traces, vessels for cooling wine, and several other domestic purposes.

Prevention of Damp.

Ar a period when this subject has assumed such an important aspect, the following extract frem a communication made by J. I. Hawkins, Esq., to the Editor of the "Architectural Magazine," in the year 1834, may not be devoid of interest:

THE ENGLISH NAVIE.-The English navie has carried a knowledge of his craft into countries where the arts of digging and handling "Soon after I had taken a lease (ten years the spade were in their infancy. It may seem since) of the cottage I now occupy, I dis- ridiculous to talk of there being "an art" in covered that the damp ascended the walls to shovelling earth into a barrow; but it is an the height of a yard above the ground, and art, and a very important one. It is quite that my furniture began to be injured by mil- English. The very spade is English, and so dew. Finding that the foundation was laid are the pickaxe and wheelbarrow. All over upon a subsoil of clay, and knowing that a continental Europe, the instrument of digging cure would be effected by interposing a water- is a clumsy species of adze; and that for lifting proof medium throughout the thickness of the is a long pole with a small shovel at the end of wall, just above the level of the ground, I pro- it. The short shovel with a cross handle is ceeded in the following manner:-First, English; the French and Germans know nomade a hole through the wall, over the ground thing of it, except as a new importation. With course, taking out two courses in height and the short English spade or shovel, a navie will two bricks in length; consequently, the hole with ease lift, in a given space of time, six was 6 in. high and 18 in. wide. I filled up times the quantity of earth that a Frenchman half this hole, at one end, with two courses of will do with his long-poled instrument. He sound bricks, laid in Roman cement. It is excels in the art of carrying as well as lifting. clear that the operation could not injure the On several railway workings which we have wall, the width of 18 in. not allowing of any seen on the Continent, apparently under the settlement. Two courses more, of 9 in. in charge of native contractors, the earth is filled width, were next removed, making the hole into small cars or waggons, which are drawn again 18 inches wide; the half of which by men or women with ropes across the soft was then filled up with bricks and ce- and uneven surface of the ground. The toil ment as before. The operation was re-and tediousness of this process are excessive; peated until the whole of the walls of the and the spectacle makes one melancholy. house were underpinned by two courses of "Can it be possible," you say to yourself, hard bricks and three joints of Roman cement; "that they don't know of the wheelbarrow?" constituting a waterproof septum, through which the damp cannot rise.

"Local circumstances prevented easy access to two or three spots; and, my bricklayer not taking care that there should be three perfect joints of Roman cement in every part, the moisture still rises, in a few neglected places, in a small degree. But, with these few exceptions, the cottage, generally speaking, has been as free from damp, for nearly ten years, as if built upon a dry subsoil. The cost of 120 ft. run of wall, for the most part 14 in. thick, was about £15.

This little vehicle, homely as it appears, is entitled to be associated with the most stupendous undertakings. Pushed along on a plankanother English invention-by a stout navie, it forms one of our most valuable machines. The great or wholesale carrying engine, however, of the navie, is the waggon on temporary rails. of this expert mechanism the continentalists likewise knew nothing till they saw it introduced by English contractors; and, after all, the car, dragged with difficulty by ropes, is still chiefly employed by them-a dozen men or women not doing the work of one horse! The English navie, paradoxical as it may civilisation: he carries the arts abroad, and seem, is an important agent in the spread of practically expounds their operation. Now that he has shown the French the use of the pickaxe, the short shovel, the wheelbarrow and plank, and the waggon and temporary rail, we may reasonably expect that the knowledge of these improved instruments of labour will be extended over Europe. How curious! An illiterate peasant from the fens of Lincolnshire tells the learned of France and Germany things which alter the face and condition of kingdoms, and which they never heard of before ! Philosophers who can discover "In building a house on a moist subsoil, planets, not having the ingenuity to invent a where the expense of a waterproof foundation wheelbarrow! Countries affecting to stand at might be an object, a couple of courses of the head of science, yoking women in ropebrick, laid in Roman cement, immediately harness to draw mud, and making them draw above the level of the grouud, would prevent it too, in the most unscientific manner!

"In recommending this plan, I would strongly enforce the necessity of performing the operation under every part of the house, partition walls, and chimneys. I yielded to the fears of my bricklayer, and suffered the stacks of my chimneys to remain untouched; the hearths on the ground floors are, therefore, damp, except when a constant fire is kept up. There was, in reality, no danger of any sinking of the stack, as Roman cement, when of good quality, expands in setting, and affords as perfect a support as the bricks and mortar which were taken away; or, rather, a more perfect support than they had afforded.

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