and it seems to be still advancing west couple of visitors, who came from the ward.

same province. We joined together with VARIEGATION, among botanists and the greatest pleasure. We were young, florists, the act of streaking or diversify- full of the first ardour for knowledge, ing the leaves, &c. of plants and flowers strongly united, and, what we were not with several colours. Variegation is then perhaps disposed to think so great either natural or artificial. Of natural va a happiness, little known. Varignon, who riegation there are four kinds: the first had a strong constitution, at least in his showing itself in yellow spots here and youth, spent whole days in study, without there, in the leaves of plants, called by any amusement or recreation, except gardeners the yellow bloach. The se walking sometimes in fine weather. I cond kind, called the white bioach, marks have heard him say, that in studying after the leaves with a great number of white supper, as he usually did, he was often spots, or stripes; the whitest lying next surprised to hear the clock strike two in the surface of the leaves, usually accom the morning ; and was much pleased that panied with other marks of a greenish four hours rest were sufficient to refresh white, that lie deeper in the body of the him. He did not leave his studies with leaves. The third, and most beautiful, is that heaviness which they usually create ; where the leaves are edged with white, nor with that weariness which a long ap. being owing to some disorder or infection plication might occasion. He left off gay in the juices, which stains the natural and lively, filled with pleasure, and impacomplexion or verdure of the plant. The tient to renew it. In speaking of mathefourth kind is that called the yellow edge. matics, he would laugh so freely, that it

VARIGNON (PETER,) in biography, seemed as if he had studied for diversion. was born at Caen in 1654. He was the No condition was so much to be envied son of an architect, and intended at an as his; his life was a continual enjoyment, early age for the church. Accident threw delighting in quietness.” into his way a copy of Euclid's Elements, In the solitary suburb of St. Jacques which gave him a strong bias towards he formed, however, a connection with mathematical learning. So intent was he many other learned men; as Du Hamel, in the pursuit of science, that he abridged Du Verney, De la Hire, &c. Du Verney himself of the necessaries of life, to pur- often asked his assistance in those parts chase books to aid him in the pursuit of anatomy connected with mechanics ; From his relations he met with much op- they examined together the positions of position, because they imagined that geo- the muscles, and their directions; hence metry and algebra would ill accord with Varignon learned a good deal of anatomy the course of theological studies. While from Du Verney, which he repaid by the he was at college he became acquainted application of mathematical reasoning to with the Abbé St. Pierre ; and in their that subject. application to learning, they were mutu At length, in 1687, Varignon made him. ally serviceable to one another. The self known to the public by a treatise on abbé, to enjoy more of Varignon's com new mechanics, dedicated to the Acade. pany, determined to lodge with him; and my of Sciences. His thoughts on the subsensible of his merit, he resolved to give ject were, in effect, quite new. He disbim a fortune, that he might fully pursue covered truths, and laid open their sourthe bent of his genius, and improve his ces. In this work he demonstrated the talents; and out of only 1800 livres a necessity of an equilibrium, in such cases year, which he had himself, he conferred as it happens in, though the cause of it 300 of them upon Varignon.

is not exactly known. This discovery The abbé, persuaded that he could not Varignon made by the theory of comdo better than go to Paris to study philo- pound motions, and is what this essay phy, settled there in 1686, with M. Va turns upon. This new treatise on mecha. rignon, in the suburbs of St. Jacques. nics was greatly admired by the matheThere each studied in his own way, the maticians, and procured the author two abbé applying himself to the study of considerable places, the one of geometrimen, manners, and the principles of go. cian in the Academy of Sciences, the vernment; whilst Varignon was wholly other of professor of mathematics in the occupied with the mathematics.

college of Mazarine; to this honour he “I,says Fontenelle, “ who was their was the first person raised. countryman, often went to see them, Varignon catched eagerly at the scisometimes spending two or three days ence of infinitesimals as soon as it appear. with them. They had also room for a ed in the world, and became one of its

most early cultivators. Severe and unre. bright colour, amber.powder must de dismitted study injured bis bealth very solved in transparent painter's varnish, in much, and in 1705 he had a dangerous Papin's machine, by a gentle fire. illness, wbich confined him to his bed As an instance of the second sort of many months, and the effects of which he lac varnishes with etherial oils alone, did not recover for three years Indeed may be adduced the varnish made with it can scarcely be said that he ever per oil of turpentine. For making this, masfectly regained the vigour which he had tich alone is dissolved in oil of turpentine formerly enjoyed. He could not lay aside by a very gentle digesting heat, in close . his studies, and these were deemed in. glass vessels. This is the varnish used for compatible with his health. He died in the modern transparencies employed as 1722 : by Fontenelle he is described as window blinds, fire-screens, and for other an excellent man, not apt to be jealous of purposes. These are commonly prints, the fame of others; he was as simple in coloured on both sides, and afterward his manners as his understanding was su coated with this varnish on those parts perior. He was at the head of the French that are intended to be transparent. mathematicians, and one of the best in Sometimes fine thin calico, or Irish linen, Europe. He was apt to be over hasty is used for this purpose; but it requires when a new object presented itself; and to be primed with a solution of isinglass, too impetuous towards those who oppos. before the colour is laid on. ed him. His works, which were published Copal may be dissolved in genuine separately, were “ Projet d'une nouvelle Chio turpentine, according to Mr. Shel. Mechanique,” 4to.“ Des nouvelles Con- drake, by adding it in powder to the tur. jectures sur la Pesanteur.” “Nouvelle pentine previously melted, and stirring Mechanique ou Statique.” Besides a vast till the whole is fused. Oil of turpentine number of separate memoirs.

may then be added to dilute it sufficient. VARNISH. Lac varnishes, or lacquers, ly. Or the copal in powder may be put consist of different resins in a state of so into a long-necked mattrass with twelve lution, of which the most common are, parts of oil of turpentine, and digested mastich, sandarach, lac, benzoin, copal, several days on a sand-heat, frequently amber, and asphaltum The menstrua are shaking it. This may be diluted with one either expressed or essential oils, as also fourth or one fifth of alcohol. Metallic alcohol. For a lac varnish of the first vessels, or instruments, covered with two kind, the common painter's varnish is to or three coats of this, and dried in an be united, by gently boiling it with some oven each time, may be washed with more mastich or colophony, and then di- boiling water, or even exposed to a still luted again with a little more oil of tur greater heat, without injury to the varpentine. The latter addition promotes nish. both the glossy appearance and drying of A varnish of the consistence of thin the varnish.

turpentine is obtained for aërostatic ma. Of this sort is the amber varnish. To chines, by the digestion of one part of make this varnish, half a pound of amber elastic gum, or caoutchouc, cut into is kept over a gentle fire in a covered small pieces, in thirty-two parts of rectiiron pot, in the lid of which there is a fied oil of turpentine. Previously to its small hole, till it is observed to become being used, however, it must be passed soft, and to be melted together into one through a linen cloth, in order that the

As soon as this is perceived, the undissolved parts may be left behind. vessel is taken from off the fire, and suf The third sort of lac-varnishes consists fered to cool a little; when a pound of in the spirit-varnish. The most solid re. good painter's varnish is added to it, and sins yield the most durable varnishes ; the whole suffered to boil up again over but a varnish must never be expected to the fire, keeping it continually stirring. be harder than the resin naturally is of After this, it is again removed from the which it is made. Hence, it is the height fire ; and when it is become somewhat of absurdity to suppose that there are cool, a pound of oil of turpentine is to be any incombustible varnishes, since there gradually mixed with it. Should the var. is no such thing at an incombustible re. nish, when it is cool, happen to be yet sin. But the most solid resins by them. too thick, it may be attenuated with more selves produce brittle varnishes: there. oil of turpentine. This varnish has al. fore something of a softer substance must ways a dark brown colour, because the always be mixed with them, whereby amber is previously half-burned in this this brittleness is diminished. For this operation ; but if it be required of a purpose, gum elemi, turpentine, or bal


sam of capaiva, are employed in proper tree is propagated by off-sets. When the proportions. For the solution of these cultivator is desirous of planting it, he bodies the strongest alcohol ought to be takes a branch, which he wraps up in a used, which may very properly indeed be mass of earth, my means of fax. Care is distilled over alkali, but must not have taken to moisten this earth; the branch stood upon alkali. The utmost simplicity pushes out roots, and is then pruned and in composition, with respect to the num. transplanted. This tree grows to the size ber of the ingredients in a formula, is the of a man's leg. result of the greatest skill in the art; The varnish is drawn in spring. If it hence it is no wonder, that the greatest be a cultivated tree, it affords three ga. part of the formulas and recipes that we therings. It is extracted by incisions meet with are composed without any made in the spring: and when the varprinciple at all.

nish, which is received in shells, does not In conformity to these rules, a fine co flow, several bog's bristles, moistened lourless varnish may be obtained, by dis with water or saliva, are introduced into solving eight ounces of gum sandarach the wound, and cause it to run. When and two ounces of Venice turpentine in the tree is exhausted, the upper part of thirty-two ounces of alcohol by a gentle it is wrapped in straw, which is set on heat. Five ounces of shell-lac and one of fire, and causes the varnish to precipiturpentine, dissolved in thirty-two ounces tate to the boitom of the tree, where it of alcohol by a very gentle heat, give a flows out of perforations made for that harder varnish, but of a reddish cast. To purpose. these the solution of copal is undoubted Those who collect the varnish set out ly preferable in many respects. This is before day-break, and place their shells effected by triturating an ounce of pow. beneath the apertures. The shells are not der of gum copal, which has been well left longer than three hours in their place, dried by a gentle heat, with a drachm of because the heat of the sun would evapocamphor, and, while these are mixing to rate the varnish. gether, adding by degrees four ounces of The varnish emits a smell, which the the strongest alcohol, without any diges. workmen are very careful to avoid respirtion.

ing. It produces an effect which they call Between this and the gold varnish the bud of the varnish. there is only this difference, that some When the varnish issues from the tree substances that communicate a yellow it resembles pitch. By exposure to the tinge are to be added to the latter. air, it gradually becomes coloured, and is, The most ancient description of two at last, of a beautiful black. sorts of it, one of which was prepared The juice which flows from incisions with oil, and the other with alcohol, is to made in the trunk and branches of the be found in “ Alexius Pedemontanus Dei rhus toxicodendron possesses the same Secreti,” Lucca, of which the first edition properties. It is a white milky fluid, was published in the year 1557. But it is which becomes black and thick by the better prepared, and more durable, when contact of the air. made after the following prescription : To make the varnish bright, it is evaTake two ounces of shell-lac, of arnatto porated by the sun: and a body is given and turmeric of each one ounce, and thir.

to it with hog's gall and sulphate of iron. ty grains of fine dragon's blood, and

The Chinese use the oil of tea, which make an extract with twenty ounces of they render drier by boiling it with orpialcohol in a gentle heat.

ment, realgar, and arsenic. Oil varnishes are commonly mixed im. mediately with the colours, but lac or lac

To varnish any substance, consists in quer varnishes are laid on by themselves applying upon its surface, a covering of upon a burnished coloured ground: when

such a nature, as shall defend it from the they are intended to be laid upon naked influence of the air, and give it a shining wood, a ground should be first given appearance. them of strong size, either alone or with A coat of varnish ought, therefore, to some earthy colour, mixed up with it by possess the following properties : 1. It levigation. The gold lacquer is simply must exclude the action of the air; berubbed over brass, tin, or silver, to give cause wood and metals are varnished, to them a gold colour.

defend them from decay and rust. 2. It Pere d'Incarville has informed us, that must resist water; for otherwise the efthe tree which affords the varnish of Chi- fect of the varnish could not be permana is called tsi-chou by the Chinese. This nent. 3. It ought not to alter such co

[ocr errors]

lours as are intended to be preserved by first, and smalt for the second. See this means.

ENAMELLING. It is necessary, therefore, that a var Varnish, among medalists, signifies the nish should be easily extended or spread colours antique medals have acquired in over the surface, without leaving pores the earth. The beauty which nature or cavities, that it should not crack nor alone is able to give to medals, and art scale; and that it should resist water. has never yet attained to counterfeit, enNow resins are the only bodies that pos- hances the value of them; that is, the sess these properties.

colour which certain soils in which they Resins, consequently, must be used as have a long time lain tinges the metals the bases of varnish. The question which withal ; some of which are blue; others of course presents itself must be, then, with an inimitable vermilion colour; how to dispose them for this use; and for others with a certain shining polished this purpose they must be dissolved, as brown, vastly finer than Brazil figures. minutely divided as possible, and com VARRONIA, in botany, so named bined in such a manner, that the imper- from Marcus Terentius Varro, a genus of fections of those which might be dis. the Pentandria Monogynia class and orposed to scale may be corrected by der Natural order of Asperifoliæ. Borothers.

raginer, Jussieu. Essential character: Resins may be dissolved by three corolla five-cleft; drupe with a four-celled agents : 1. By fixed oil. 2. By volatile

nut. The are nine species. oil. 3. By alcohol. And accordingly we VAS, a vessel either for mechanical, have three kinds of varnish: the fat or oily chemical, culinary, or any other uses. In varnish, essential varnish, and spirit var. anatomy, all the parts which convey a nish.

fluid are called vessels, as the veins, arteBefore a resin is dissolved in a fixed ries and lymphatics. oil, it is necessary to render the oil dry VASA concordiæ, among hydraulic alia ing. For this purpose the oil is boiled thors, are two vessels, so constructed as with metallic oxides, in which operation that one of them, though full of wine, the mucilage of the oil combines with the will not run a drop, unless the other, bemetal, while the oil itself unites with the ing full of water, do run also. oxygen of the oxide. To accelerate the

VASE, a term frequently used for andrying of this varnish, it is necessary to cient vessels dug from under ground, or add oil of turpentine.

otherwise found, and preserved in the caThe essential varnishes consist of a so. binets of the curious. In architecture, lution of resin in oil of turpentine. The the appellation vase is also given to those varnish being applied, the essential oil ornaments placed on corniches, sochles, flies off, and leaves the 'resin. This is or pedestals, representing the vessels of used only for paintings.

the ancients, particularly those used in When resins are dissolved in alcohol, sacrifice; as incense pots, flower-pots, the varnish dries very speedily, and is &c. They serve to crown or finish fasubject to crack; but this fault is correct. çades or frontispieces; and hence called ed by adding a small quantity of turpen. acroteria. The term vase, however, is tine to the mixture, which renders it more particularly used in architecture to brighter, and less brittle when dry. signify the body of the Corinthian and

The coloured resins, or gums, such as Composite capital; otherwise called the gamboge, dragon's blood, &c. are used to tambour or drum, and sometimes the colour varnishes.

campana or bell. To give lustre to the varnish after it is VATERIA, in botany, so named from laid on, it is rubbed with pounded pumice. Abraham Vater, professor of medicine stone and water: which being dried with and botany, at Witteberg, a genus of the a cloth, the work is afterward rubbed with Polyandria Monogynia class and order, an oiled rag and tripoli. The surface is, Natural order of Guttiferæ, Jussieu, Eslast of all, cleaned with soft linen cloths, sential character: calys five-cleft; corolcleared of all greasiness with powder of la five petalled; capsule three-valved, starch, and rubbed bright with the palm one-celled, three-seeded. There is only of the hand.

one speci viz. V. indica. Varnish also signifies a sort of shin. VATICA, in botany, a genus of the Doing coat, wherewith potter's ware, delft. decandria Monogynia class and order. Naware, china-ware, &c. are covered, which tural order of Guttiferæ, Jussieu. Essengives them a smoothness and lustre. tial character: calyx five-cleft; petals Melted lead is generally used for the five; anthers fifteen, sessile, four-celled.

[ocr errors]

There iş but one species, viz. V. shinen

each other in all directions, and is şuccyşis, a very rare plant, and as yet scarcely lent and tender. known.

The cortical layers, which constitute VATICAN, a magnificent palace of the the interior part of the bark, are composPope, in Rome, which is said to consisted of thin membranes, and increase in of several thousand rooms; but the parts number with the age of the plant. The. of it most admired are, the grand stair. wood immediately under the bark is comcase, the Pope's apartment, and especial. posed of concentric layers, which increase ly the library, which is one of the richest with the age of the plant, and may be se. in the world, both in printed books and parated into thinner layers, which are manuscripts.

composed of longitudinal fibres. The

wood next the bark, which is softer and VAULT, in architecture, an arched roof, so contrived that the stones which whiter, is called the alburnum. The in: forma it sustain each other. Vaults are, harder, and is denominated the perfect

terior part of the trunk is browner and on many occasions, to be preferred to

wood. soffits, or flat ceilings, as they give a great.

In the middle of the stem is the pith, er height and elevation, and are besides more firm and durable.

which is a soft, spongy substance, composed of cells.

In old wood this part enVECTOR, or Radius Vector, in astrono- tirely disappears, and its place is occupimy, is a line supposed to be drawn from ed by the perfect wood. any planet moving round a centre, or the The leaves are composed of fibres arfocus of an ellipse, to that centre, or fo- ranged in the form of net-work, which

It is so called, because it is that proceed from the stem and foot-stalk, by line by which the planet seems to be car which they are attached to the branches. ried round its centre; and with which it These fibres form two layers in each leaf, deseribes areas proportional to the times. which are destined to perform different

VEER, a sea term, variously used. functions. The leaves are covered with Thus veering out a rope, denotes the let- the epidermis, which is common to the ting it go by hand, or letting it run out whole of the plant. Each surface of a of itself. It is not for letting out any leaf has a great number of pores and running rope except the sheet.

glands, which absorb or emit elastic VEGETABLE. See BOTANY, PLANT,

fluids. &c. A vegetable is composed of a root,

Flowers are composed of different parts. stem, leaves, flowers, fruits, and seeds; The calyx or cup is formed by the extenand when all these different parts are ful sion of the epidermis; the corolla is a con. ly developed, the vegetable is said to be tinuation of the bark, and the stamina perfect. When any are deficient, or at

and pistilla, the internal parts of fructificaleast less obvious, the vegetable is said to tion, are composed of the woody fibres be imperfect. The root is that part of and pith of the plant. Fruits are usually the plant which is concealed in the earth, composed of a pulpy parenchymatous and which serves to convey nourishment substance, containing a great number of to the whole plant. The stem, which vesicles, and traversed by numerous ves. commences at the termination of the root, sels. Seeds are constituted of the same supports all the other parts of the plant. utricular texture, in the vesicles of which When the stern is large and solid, as in is deposited a pulverulent or mucous sub. trees, it is denominated the trunk, which

stance. These cells have a communicais divided into the wood and the bark. tion with the plants by means of vessels, The bark constitutes the outermost part and by these is conveyed the necessary of the tree, and covers the whole of the

nourishment during germination. plant from the extremity of the roots to

Plants contain different orders of ves: the termination of the branches. The sels, which are distinguished from each bark is composed of three parts, namely, other by their course, situation, and uses. the epidermis, the parenchyma, and cor Lymphatic vessels serve for the circulation tical layers. The epidermis, which is a of the sap. They are chiefly situated in thin transparent membrane, forming the the woody part of the plant. The pecu. external covering of the bark, is compos. liar vessels which generally contain thick ed of fibres crossing each other. When or coloured fluids are placed immediatethe epidermis is removed, it is reproduc- ly under the bark; they are smaller in ed. The parenchyma, which is immedi- number than the sap vessels, and have ately below the epidermis, is of a dark- thin interstices filled up with utriculi or green colour, composed of fibres crossing cells with which they form a communi.


« ForrigeFortsett »