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It occurs at Berezof, in Siberia, along with chromate of lead; and is also said to exist in Brazil.

VAUX, Nicholas, first lord Vaux, was the son of sir William Vaux, and received the honor of knighthood for his gallantry at the battle of Stoke, in 1487. He ranked high in the favor of Henry VIII, who carried him with him into France, where he was present at the celebrated meeting between that king and the French monarch in the "field of cloth of gold," and was afterwards ennobled. His death took place in 1530.-His son, Thomas lord Vaux, who inherited the talents and valor of his father, and succeeded him in the esteem of his prince, was born in 1510. He attended Henry on his second French expedition, and was made governor of Jersey, with the collar of the order of the Bath. Like many of the young nobility of the age, he joined the cultivation of poetry to the study of martial exercises; and several of his poetic effusions are yet to be found in the Paradyse of daintie Devyces, of which his Aged Lover's Renunciation of Love, and the Assault of Cupid, have been much admired. His death took place soon after the accession of Mary to the throne.

VAUXHALL GARDENS. This elegant place of summer resort is situated near the Thames, in the parish of Lambeth, about a mile and a half from Westminster bridge, and is denominated from the manor of Vauxhall. There is no certain account of the time when these premises were first opened for the entertainment of the public; but the Spring gardens at Vauxhall are mentioned in the Spectator as a place of great resort. It was formerly little more than a tea-garden, enlivened with instrumental music, but so much frequented, that the proprietor was encouraged to augment the attraction by the introduction of vocal music. These gardens are beautiful and extensive, and contain a variety of walks: when open for public amusement, they are illuminated with variegated lamps, and embellished with transparent devices. The different boxes and apartments are adorned with paintings, many of which are executed by Hogarth and Hayman. The latter has chosen his subjects from Shakspeare. In bad weather, the musical performance

is in the rotunda, seventy feet in diameter. The roof is so contrived, that sounds never vibrate under it; and thus music is heard to great advantage.

VECTOR, OF RADIUS VECTOR, in astronomy, is a line supposed to be drawn from any planet moving round a centre, or the focus of an ellipse, to that centre, or focus. It is so called, because it is that line by which the planet seems to be carried round its centre, and with which it describes areas proportional to the times.

VEDAS. (See Indian Literature, vol. vi, page 563.)

VEDETTE; a sentinel on horseback. The word is derived from the Italian vedetta (from vedere, to see), and signifies, originally, a watch-tower. It is also used, sometimes, for sentinels on foot, forming the extreme point in the line of outposts. They are often placed in pairs, in such a way that the field of vision of one intersects that of the other.

VEERING. (See Ship.)

VEGA (Spanish for valley); the name of numerous places in countries where the Spanish language is spoken.

VEGA. Don Lope Felix de Vega Carpio, generally called Lope de Vega, is described under Lope de Vega. (See also Garcilaso.)

VEGA, George, baron de, an Austrian officer of artillery, born at Sagoritz, in Carniola, in 1754. He studied at the college of Laybach, where he made a rapid progress in mathematics. Being appointed an engineer in Carniola, and afterwards in Hungary, he became known as a man of talent in his profession, and was patronised by the emperor Joseph II. He served in several campaigns against the French, and, having distinguished himself on many occasions, especially in 1796, was made a major, and afterwards a lieutenant-colonel, knight of the order of Maria Theresa, and a baron of the empire. His death took place in September, 1802. He was a member of the academies of Göttingen, Erfurt, Berlin, and several others, and was considered as a distinguished mathematician. He published a Course of Mathematics for the Use of the Artillery of the Imperial Army (Vienna, 1786–1800, 4 vols., 4to. ; 3d edit., 1802, folio); a Logarithmo-trigonometrical Manual (Leipsic, 1793, 4to.); a Complete Collection of grand Logarithmotrigonometrical Tables (1794, folio); an Introduction to Chronology (Vienna, 1801, 8vo.); and a Natural System of Measures, Weights and Coins (1803, 4to.).

VEGETABLE CHEMISTRY. The principles of which vegetables are composed, if we pursue their analysis as far as our means have hitherto allowed, are chiefly carbon, hydrogen and oxygen. Nitrogen is a constituent principle of several, but it is only present in small quantity. Potash, soda, lime, magnesia, silex, alumine, sulphur, phosphorus, iron, manganese and muriatic acid occur occasionally in plants, though in small and very variable proportions. Every distinct compound which exists already formed in plants, and which is capable of separation without suffering decomposition, is called a proximate, or immediate principle, of vegetables. Thus sugar, starch and gum are proximate principles. Opium, though obtained from a plant, is not a proximate principle, but consists of several proximate principles, mixed more or less intimately together. The proximate principles of vegetables are sometimes distributed over the whole plant, while in others they are confined to a particular part. The methods by which they are procured are very variable. Thus gum exudes spontaneously, and the saccharine juice of the mapletree is obtained by incisions made in the bark. In some cases, a particular principle is mixed with such a variety of others, that a distinct process is required for its separation. Of such processes consists the proximate analysis of vegetables. Sometimes a substance is separated by mechanical means, as in the preparation of starch. On other occasions, advantage is taken of the volatility of a compound, or of its solubility in some particular menstruum. Whatever method is employed, it should be of such a nature as to occasion no change in the composition of the body to be prepared. The reduction of the proximate principles into their simplest parts constitutes their ultimate analysis. By this means the quantity of oxygen, carbon and bydrogen present in any compound is ascertained. The method by which this is accomplished is, to convert the whole of the carbon into carbonic acid, and the hydrogen into water, by means of some compound which contains oxygen in so loose a state of combination as to give it up to those elements at a red heat. The substance employed is the peroxide of copper, which, if alone, may be heated to whiteness without parting with oxygen; whereas it yields oxygen readily to any combustible matter with which it is ignited. It is easy, therefore, by weighing it before and after analysis, to discover

the precise quantity of oxygen which has entered into union with the carbon and hydrogen of the substance submitted to examination. The constitution of vegetable substances is not yet sufficiently known to admit of their being classified in a purely scientific order. The chief data hitherto furbished towards forming a systematic arrangement, are derived from a remarkable agreement between the composition and general properties of several vegetable compounds. From the ultimate analysis of a considerable variety of proximate principles the three following conclusions are drawn: 1. a vegetable substance is always acid when it contains more than a sufficient quantity of oxygen for converting all its hydrogen into water; 2. it is always resinous, oily or alcoholic, &c., when it contains less than a sufficient quantity of oxygen for combining with the hydrogen; and 3. it is neither acid nor resinous, but in a state analogous to sugar, gum, starch, or the woody fibre, when the oxygen and hydrogen which it contains are in the exact proportion for forming water. These laws, indeed, are not rigidly exact, nor do they include the vegetable products containing nitrogen. M. Thenard has divided the proximate principles into five classes. The first includes the vegetable acids; the second, vegetable alkalies; the third, those substances which contain an excess of hydrogen; the fourth, those the oxygen and hydrogen of which are in proportion for forming water; and the fifth, those bodies which, so far as is known, do not belong to either of the other divisions.-1. The vegetable acids are decomposed by a red heat. They are, in general, less liable to spontaneous decomposition than other vegetable substances. They are nearly all decomposed by concentrated hot nitric acid, by which they are converted into carbonic acid and water. They are at least twenty-five in number, the most important of which are the following: acetic acid, or vinegar (q. v.), oxalic (q. v.), tartaric (q. v.), citric (q. v.), malic, benzoic (q. v.), gallic (q. v.) boletic, moroxylic (q. v.), meconie and pectic acids.-2. Under the title of vegetable alkalies are comprehended those proximate principles which are possessed of alkaline properties. They all consist of carbon, hydrogen, oxygen and nitrogen. They are decomposed with facility by nitric acid and by heat; and ammonia is always one of the products of the destructive distillation. They never exist in an insulated state in the plants which contain

them, but are, apparently, in every case, combined with an acid, with which they form a salt more or less soluble in water. These alkalies are, for the most part, very insoluble in water, and of sparing solubility in cold alcohol; but they are all readily dissolved by that fluid at a boiling temperature, being deposited from the solution, commonly in the form of crystals, on cooling. Most of the salts are far more soluble in water than the alkalies themselves, and several of them are remarkable for their solubility. As the vegetable alkalies agree in several of their leading chemical properties, the mode of preparing one of them admits of being applied, with slight variation, to all. The general method is as follows: The substance containing the alkaline principle is digested, or, more commonly, macerated, in a large quantity of water, which dissolves the salt, the base of which is the vegetable alkali. On adding some more powerful salifiable base, such as potassa or ammonia, or boiling the solution for a few moments with lime or pure magnesia, the vegetable alkali is separated from its acid; and being, in that state, insoluble in water, may be collected on a filter, and washed. To purify it from certain oleaginous, resinous substances and coloring matters, it is mixed with a little animal charcoal and dissolved in boiling alcohol. This solution is filtered while hot, and evaporated to dryness, which affords the alkali in a state of perfect purity. Upwards of twenty of these bodies have already been investigated. The following are the names of those which are the most important: morphia, cinchonia, quinia, strychnia, brucia, veratria and sanguinaria. (q. v.)-3. Oils are characterized by a peculiar unctuous feel, by inflammability, and by insolubility in water. They are divided into fixed and volatile oils, the former of which are comparatively fixed in the fire, and therefore impart a permanent stain to paper; while the latter, owing to their volatility, produce a stain which disappears by gentle heat. (See Oils, and Essential Oils.)— 4. Resins are the inspissated juices of plants, and commonly occur either pure or in combination with an essential oil. They are solid at common temperatures, brittle, inodorous and insipid. They are non-conductors of electricity, and, when rubbed, become negatively electric. They are generally of a yellow color and semitransparent. They are melted by the application of heat, and, by a still higher temperature, are decomposed. In close

vessels, they yield empyreumatic oil, and a large quantity of carbureted hydrogen. In the open air, they burn with a yellow flame and much smoke, being resolved into carbonic acid and water. Resins are dissolved by alcohol, ether and the essential oils; and the alcoholic and ethereal solutions are precipitated by water, a fluid in which they are quite insoluble. Their best solvent is pure potash and soda; and they are soluble in the alkaline carbonates by the aid of heat. The product is, in each case, a soapy compound, which is decomposed by an acid. The most important are described under their respective names, in this work. Alcohol (q. v.) is the intoxicating ingredient of all spirituous and vinous liquors. It does not exist ready formed in plants, but is a product of the vinous fermentation. (See Fermentation.) Ether (q. v.) is a general term applied to several compounds produced from the action of acids on alcohol.-4. Those substances in which the oxygen and hydrogen are in the exact proportion for forming water, are sugar, starch, gum and lignin, all of which have been described, except the last. Lignin forms the fibrous structure of vegetable substances, and is the most abundant principle in plants. The different kinds of wood contain about 96 per cent. of lignin. It is prepared by digesting the sawings of any kind of wood successively in alcohol, water and dilute muriatic acid, until all the substances soluble in these menstrua are removed. It has neither taste nor odor, undergoes no change by keeping, and is insoluble in alcohol, water and the dilute acids. When the woody fibre is heated in close vessels, it yields a large quantity of impure acetic acid and charcoal. It consists of carbon 51.43, oxygen 42.73, and hydrogen 5.82.-5. Substances not belonging to either of the preceding sections. The most important of these are coloring matter, tannin, vegetable albumen, gluten, yeast, asparagin, caffein, cathartin, piperin, bitter principle, and extractive matter.

The Chemical Phenomena of Germination and Vegetation. Germination is the process by which a new plant originates from seed. A seed consists essentially of two parts-the germ of the future plant, endowed with a principle of vitality, and the cotyledons, or seed-lobes, both of which are enveloped in a common covering of cuticle. In the germ, two parts

the radicle and the plumule-may be distinguished, the former of which is destined to descend into the earth and con

extraneous

sources.

VEGETABLE CHEMISTRY.

stitute the root, the latter to rise into the
air and form the stem of the plant. The
office of the seed-lobes is to afford nour-
ishment to the young plant, until its
organization is so far advanced, that it
may draw materials for its growth from
For this reason,
seeds are composed of highly nutritious
ingredients. The chief constituent of
most of them is starch, in addition to
which they frequently contain gluten,
gum, vegetable albumen or curd, and
sugar. The conditions necessary to ger-
mination are three-fold, viz. moisture, a
certain temperature, and the presence of
oxygen gas. The necessity of moisture
to this process has been proved by ex-
tensive observation. A certain degree of
warmth is not less essential. Germina-
tion cannot take place at 32° Fahr.; and
a strong heat, such as that of boiling
water, prevents it altogether, by depriving
the germ of the vital principle. The most
favorable temperature ranges from 60°
to 80°, the precise degree varying with
the nature of the plant-a circumstance
that accounts for the difference in the
season of the year at which different
seeds begin to germinate. The presence
of air is indispensable for the germination
of seeds; but the influence of light,
which is so favorable to all the subsequent
stages of vegetation, is injurious to the
process of germination. The operation
of malting barley, in which the grain is
made to germinate by exposure to warmth,
air and humidity, affords the best means
of studying the phenomena of germina-
tion. In preparing malt, the grain passes
through four stages, called steeping, couch-
ing, flooring and kiln-drying. In the first,
it is steeped in water for about two days,
when it absorbs moisture, softens, and
swells considerably. It is then removed
to the couch frame, where it is laid in
heaps, thirty inches in depth, from twen-
ty-six to thirty hours. In this situation,
the grain becomes warm, and acquires a
disposition to germinate; but as the tem-
perature, in such large heaps, would rise
very unequally, and germination conse-
quently be rapid in some portions and
slow in others, the process of flooring is
employed. This consists in laying the
grain in strata a few inches thick, on
large, airy, but shaded floors, where it re-
mains for about twelve or fourteen days,
until germination has advanced to the
extent desired by the maltster. During
this interval, the grain is frequently turned,
in order that the temperature of the
whole mass may be uniform. As soon

as saccharine matter is freely developed,
germination must be arrested; since,
otherwise, being taken up as nutriment
for the young plant, it would speedily
disappear. Accordingly, the grain is
removed to the kiln, where it is exposed
to a temperature gradually rising from
100° to 160°, or rather higher; the object
being first to dry the grain completely,
and then to provide against any recurrence
of germination, by destroying the vitality
of the plant. The difference between
malted and unmalted barley is readily
perceived by the taste; but it will be
more correctly appreciated by inspecting
the result of a comparative analysis of

the two.

Resin,
Gum,

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Sugar,

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Gluten,

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Starch,

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Hordein,

12

It hence appears, that, during germina-
tion, the hordein is converted into starch,
gum and sugar; so that, from an insol-
uble material, which could not, in that
state, be applied to the uses of the young
plant, two soluble and highly nutritious
principles result, which, by being dissolv-
ed in water, are readily absorbed by the
radicle. In the growth of plants, a strik-
ing analogy to that of animals is noticea-
ble. The root serves the purpose of a
stomach, by imbibing nutritious juices
from the soil, and thus supplying the plant
with materials for its growth. The sap,
or circulating fluid, composed of water,
holding in solution saline, extractive, muci-
laginous, saccharine, and other substances,
rises upwards through the wood in a
distinct system of tubes, called the com-
mon vessels, which correspond in their
office to the lacteals and pulmonary arte-
ries of animals, and are distributed in
minute ramifications over the surface of
the leaves. In its passage through this
organ, which may be termed the lungs of
plants, the sap is fully exposed to the
agency of light and air, experiences a
change, by which it is more fully adapted
to the wants of the vegetable economy,
and then descends through the inner layer
of the bark in another system of tubes,
called the proper vessels, yielding, in its
course, all the juices and principles pecu-
liar to the plant. Plants absorb carbonic
acid from the air, under certain circum-
stances, and emit oxygen in return.
When a healthy plant, the roots of which

are supplied with proper nourishment, is exposed to the direct solar beams in a given quantity of atmospheric air, the carbonic acid, after a certain interval, is removed, and an equal volume of oxygen is substituted for it. If a fresh portion of carbonic acid is supplied, the same result will ensue. But this change only takes place in the sunshine: in the dark, an opposite effect takes place; oxygen disappears, and carbonic acid is evolved. In the dark, therefore, vegetables deteriorate rather than purify the air, producing the same effect as the respiration of animals. Plants appear to derive a large proportion of their carbon from the carbonic acid of the atmosphere. Light is necessary to the color of plants. The green color of the leaves is not developed, except when they are in a situation to absorb carbonic acid, and give out oxygen. With respect to the food of plants, the chief source from which plants derive the materials for their growth, is the soil. However various the composition of the soil, it consists, essentially, of two parts, so far as its solid constituents are concerned. One is a certain quantity of earthy matters, such as siliceous earth, clay, lime, and sometimes magnesia; and the other is formed from the remains of animal and vegetable substances, which, when mixed with the former, constitute common mould. A mixture of this kind, moistened by rain, affords the proper nourishment of plants. The water, percolating through the mould, dissolves the soluble salts with which it comes in contact, together with the gaseous, extractive, and other matters, which are formed during the decomposition of the animal and vegetable remains. In this state it is readily absorbed by the roots, and conveyed as sap to the leaves, where it undergoes a process of assimilation. But, though this is the natural process by which plants obtain the greater part of their nourishment, and without which they do not arrive at perfect maturity, they may live, grow, and even increase in weight, when wholly deprived of nutrition from this source. Thus it is well known, that many plants grow when merely suspended in the air. Without water, plants speedily wither and die. It gives the soft parts that degree of succulence necessary for the performance of their functions; it affords two elements, oxygen and hydrogen, which, either as water, or under some other form, are contained in all vegetable products; and lastly, the roots absorb from the soil those substances only

which are dissolved or suspended in water. So carefully, indeed, has nature provided against the chance of deficient moisture, that the leaves are endowed with a property both of absorbing aqueous vapor directly from the atmosphere, and of lowering their temperature during the night by radiation, so as to cause a deposition of dew upon their surface, in consequence of which, during the driest seasons, and in the warmest climates, they frequently continue to convey this fluid to the plant, when it can no longer be obtained in sufficient quantity from the soil. But, necessary as is this fluid to vegetable life, it cannot yield to plants a principle which it does not possess. The carbonaceous matter which accumulates in plants, under the circumstances above alluded to, may with certainty be attributed to the atmosphere, since we know that carbonic acid exists there, and that growing vegetables have the property of taking carbon from that gas. When plants are incinerated, their ashes are found to contain saline and earthy matters, the elements of which, if not the compounds themselves, are supposed to be derived from the soil. Such, at least, is the view deducible from accurate researches and from chemical principles. Some later experiments, however, would seem to lead to a different conclusion. Several kinds of grain, such as barley, wheat, rye and oats, in pure flowers of sulphur, were supplied with nothing but air, light, and distilled water; on incinerating the plants thus treated, they yielded a greater quantity of saline and earthy matters than were originally present in the seeds. These results may be accounted for in two ways. It may be supposed, in the first place, that the foreign matters were introduced accidentally from extraneous sources, as by fine particles of dust floating in the atmosphere; or, secondly, it may be conceived, that they were derived from the sulphur, air and water, with which the plants were supplied. If the latter opinion be adopted, we must infer either that the vital principle, which certainly controls chemical affinity in a surprising manner, and directs this power in the production of new compounds from elementary bodies, may likewise convert one element into another; or that some of the substances supposed by chemists to be simple, such as oxygen and hydrogen. are compounds, not of two, but of a variety, of different principles. But as these conjectures are at variance with the facts and principles of

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