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WAVE

its origin from a different point at some distance from the first, the two sets will cross each other without the slightest interruption. Where a wave of the first series meets one of the second, and the two elevations correspond, the resulting elevation will be equal to the sum of the two; and the same is the case with the depressions. Where the elevation in the one series corresponds with a depression in the other, the surface will maintain its original level, at least if the waves of the two series have the same height. Thus, although different series of waves do not interfere with each other's propagation, they may nevertheless increase or neutralise each other's effects. The one series is, in fact, superposed on the other.

A series of waves meeting a vertical obstacle, as a wall or bank, is reflected; and the reflected waves are propagated in the same manner as those arising from the original impulse, but in an opposite direction. Waves proceeding in concentric circles are reflected in concentric circles, in such a manner as to diverge apparently from a centre as far behind the obstacle as the original centre is in front of it; they appear, in short, to be subjected to all those laws which are usually noticed to belong to reflected light.

If the obstacle against which the waves strike have an opening in it of small horizontal breadth relatively to the breadth of the wave, the oscillating columns which reach it will act as an impulse originally exerted at that point, and a series of waves will diverge from the aperture as from a new centre; but when the aperture is considerably wider than the wave, the wave confines its motion in a great measure to its original direction, though with some small divergence, or the oscillation is continued principally in the direction of a sector, whose centre is at the point from which the original wave proceeded.

Waves which have been raised by the wind in the open sea proceed in parallel and nearly straight lines; and the original impulse being increased by the continual action of the wind, they will increase in height until the weight of the elevated column, together with the friction, becomes equal to the inciting cause. It has been inferred that the greatest height to which a single series of waves raised by the wind blowing constantly in one direction will attain does not exceed six feet. But several series of waves moving with different velocities may co-exist upon the ocean, and thus the crests of two or even three waves may be superimposed upon each other, producing the tremendous seas, three of which are usually succeeded by comparatively smooth water, because the hollows of the one series are then filled up by the crests of the other. The force of the wind also tends to give a progressive motion to the mass of water raised above the general level, and likewise to alter the shape of the wave by diminishing the acclivity of the side against which it strikes. In a strong gale this effect may be increased VOL. III.

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WAX

so far as to cause the top of the wave to project over the base, in which case it breaks and rolls over on the preceding wave. Hence, as sailors well know, a very strong wind will blow the sea down.

If the wind, after having given rise to a series of waves, suddenly veers about so as to strike waves on the opposite side, it will produce a greater effect from its more direct impact; and hence the greatest waves are produced by sudden changes of wind, or by the wind blowing in an opposite direction to that in which the waves are propagated. In this manner the elevation of the waves may be greatly increased above the height to which they would be raised by winds of equal force blowing constantly in the same direction. Hence the ocean is comparatively smooth in regions where the winds are constant; and as it is by the friction of the wind on the water that the waves are raised and kept up, whatever diminishes the friction will tend to lessen the elevation. Hence the comparative tranquillity produced by pouring oil on agitated water.

Wave-offering. In the Old Testament (Ex. xxix., Lev., and Num.), an offering which when held aloft by the priest was waved, signifying symbolically that it might be eaten by the worshippers: whereas such as were heaved were appropriated to the priests.

Wavellite. A hydrated phosphate of alumina, found generally in small crystals forming hemispherical or globular concretions with a radiated structure. It is met with at St. Austell in Cornwall, on the clay-slate of Barnstaple in Devonshire, near Freiberg in Saxony, in Bohemia, &c. It is named after Dr. Wavell, the discoverer.

Wax (A.-Sax. væx, Ger. wachs). This is a common vegetable product, forming the varnish which coats the leaves of certain plants and trees. It is also found upon some berries, as of the Myrica cerifera; and it is an ingredient of the pollen of flowers. It was long supposed that bees merely collected the wax thus ready formed in plants; but Huber found that though excluded from all food except sugar, they still formed wax; and accordingly it has been found that the elementary composition of bees' wax and vegetable wax is slightly different. Bees' wax is prepared by draining and washing the honeycomb, which is then melted in boiling water, strained, and cast into cakes. English wax and foreign wax are found in the market; the latter being chiefly imported from the Baltic, the Levant, and the coast of Barbary. Fresh wax has a peculiar honey-like odour: its specific gravity is 96. At about 150° it fuses, and at a high temperature volatilises, and burns with a bright white flame. It is bleached by being exposed in thin slices or ribands to light, air, and moisture, or more rapidly by the action of chlorine; but in the latter case it does not answer for the manufacture of candles, which is one of its principal applications. Wax candles are made by suspending the wicks upon a hoop over the cauldron of melted wax, which 3 T

WAX OPAL

called ceroplastic art, i.e. modelling and castAnother kind of wax modelling is the soing in wax itself, not merely using the wax as a means of producing casts in other substances. To this class belong wax images; wax fruit and flowers, together with the wax ana tomical and pathological models, now much in vogue, and of which many extraordinary examples exist in Florence, Paris, and London. Nearly all these wax models are cast from moulds; the mould may be in plaster of Paris, or a composition of bees' wax, Burgundy pitch, and Venice turpentine, with a very little olive oil. This composition has the great advantage of being elastic, and when thin can be peeled off the cast.

is successively poured over them from a ladle | then be filled in with a core, and proceeded with WEALDEN FORMATION till they have acquired the proper size, so that as above. the candle consists of a series of layers of wax; the upper end is then shaped, and the lower cut off. Bleached or white wax is generally adulterated with more or less spermaceti, and sold at different prices accordingly; in this case it has not the peculiar lustre of pure wax, and is softer and more fusible. It is also largely adulterated with stearin or stearic acid, which is detected by the odour of fat or tallow which it evolves when highly heated, and by its crumbly texture; it may also be separated to a certain extent by ether or alcohol. Wax is insoluble in water, and scarcely acted upon by the acids, so that it forms a good lute or cement: boiling alcohol and ether partially dissolve it, and deposit the portion which they had dissolved on cooling. According to Brodie (Phil. Trans. 1847-49), bees' stances separable by boiling alcohol, viz. myriwax contains three subcin (C92H9204), which is insoluble; cerin (C54H4O4), which is deposited in crystals as the solution cools; and cerolein, which is retained in solution. Their relative proportions vary, but in ordinary bees' wax there appears to be about 73 per cent. of myricin, 22 of cerin, and 5 of cerolein. [APIS; HIVES, BEE.]

Wax Opal. An inferior kind of Common Opal.

Wax-modelling. formerly much used by sculptors in forming Wax is a substance their models, and still greatly used by silversmiths. The founder's wax was commonly mixed with a little tallow, turpentine, and pitch, the quantity of wax being about ten to one of each of the other ingredients. Wax was especially used for hollow casting: when the safemould from the model was completed, it was filled in to a certain thickness with wax, and fixed, properly supported, in its place; the remaining cavity was then filled from the top with a fire-proof composition of plaster and brick-dust, to form a core. The mould was now removed, and a complete wax model showed itself; this the sculptor carefully revised, and again covered with a fire-proof mould of plaster, brick-dust, cowhair, and horsedung, put on with a brush in various layers; when it had reached a sufficient thickness, and was properly supported, a coal fire was kindled round it, and vents being prepared, every particle of wax was burnt out of it-a very anxious and tedious process. The whole was then bricked up and the pit filled with sand; the molten metal then took the place of the wax, and the cast was accomplished. Clay and sand modelling has now generally superseded this old wax method. taking a wax cast is, to invert the mould in A very simple mode of cold water, thus giving it a cold damp surface which instantly chills the molten wax poured into it at the points of contact, while the main bulk, remaining in a liquid state, will run out again as soon as the mould is turned over, giving the desired wax shell. This shell must 1010

pulp and size, paint this mask in strong local
a cheap method is to mould the face in paper
Wax images also are made by casting, but
colours, and then cover with two or three coats
of fine wax: the colours will show through the
wax, and the mask will require only the eyes
and hair to be added; local effects can be
modified by painting with wax and turpentine.
(Wornum On Wax-modelling' in the Supple-
ment to the Penny Cyclopædia.)

progress. A ship in progress is said to have
Way (A.-Sax. wæg). The Sea term for
Steering power is proportionate to way.
way upon her; when stationary, to have no way.

of Commons goes into committee of the whole
Ways and Means.
house for the purpose of considering the
When the House
manner in which funds are to be raised for
the public expenditure, it is said to go into
committee of ways and means.

Viburnum Lantana.
Wayfaring-tree. A common name for

in Geology to certain deposits occurring in EngWealden Formation. The name given land in the Weald or Wolds (wooded portions) of Kent, and hence to other contemporaneous rocks elsewhere. The Wealden deposits occur between the oolitic and cretaceous series. They are in England almost entirely of fresh-water origin, and include clays, sandstones, and limestones. The following is the series:

with Cypris.
1. Weald Clay of Surrey, Kent, and Sussex,
Fresh water.

burton beds, separated by the Wadhurst clay
2. Hastings Sands. Tunbridge and Ash-
and Ashdown sands, containing cale grit. Not-
withstanding the name, the argillaceous element
preponderates over the sand in this division as
well as the other.

been traced for about 200 miles from east to
3. Purbeck beds. The Wealden beds have
west to south-east. They probably represent
west, and about the same distance from north-
a large delta, not, however, larger than many
existing river deltas.

treat this formation as distinct and interpolated.
Its representatives in time certainly connect
In English Geology it is always usual to
themselves either with the overlying or under-

WEALTH

lying marine formations of other countries, though it is not always possible to say with which.

The Wealden series in the typical Wealden district of England consists of the deposits called HASTINGS SANDS, which repose on the PURBECK STRATA. The uppermost member is the WEALD CLAY, a well-defined argillaceous band, loaded with minute cases of the bivalve crustaceans, and reaching round between the chalk and the Hastings sands. Between the sands and the clays, however, are sandstones and shelly limestones, the latter of which include a bed capable of taking a polish, and known as the Sussex marble. This bed is very characteristic. Among the limestones are valuable ironstones.

The Wealden series has always been regarded as the accumulations made at the mouth of a considerable river coming in from the west. The deposits extend, but are very poorly exhibited, across the Channel on the coast of France near Boulogne; and beds distinctly contemporaneous are found in Scotland, Westphalia, and Hanover. The latter are important from their magnitude and thickness. They consist of sandstones.

WEAR

that mechanical labour is part of public wealth. But it is difficult to see how manual labour can be called wealth, and mental labour be treated differently. Of course by labour is meant the concrete notion, i.e. the persons of those who proffer services. Money is wealth only in so far as it is the requisite machinery of commerce. Hence those communities which are best informed of the nature of money seek to diminish the amount of money which they employ to the least possible amount consistent with the convenience of exchange. The theory that money is wealth per se, was the enduring fallacy of past times. Nor again, when the aggregate of national wealth is estimated, must the rent of the natural powers of the soil and public debts be treated as wealth. They are both deductions from wealth, the former being consequent on the pressure of population, the latter being a mortgage on the future productiveness of the community. Some, however, who have attempted to reckon the amount of national wealth, have carelessly included these elements.

National wealth is not a quantity, but a ratio. In the middle ages, Genoa and Venice were esteemed wealthy, and were really so. But it is probable that even taking into account the different value of money, the imports and exports of either of these cities did not equal those of a

The denudation of the Weald, or the laying bare of the tract in which these river deposits are present, is a remarkable and interesting geo-third-rate British port at the present time. Again, logical phenomenon. [VALLEY OF ELEVATION.] The chalk has once covered the whole of the Wealden deposits, has been lifted up and fractured along a line apparently nearly parallel to that of the course of the ancient river, and then washed away for a space on each side of the fracture. It now forms two escarpments facing each other, with the Hastings sand occupying the intervening valley. The Hastings sand, much lower in geological position, is higher in some places than the general level of the top of the chalk hills on each side. The time occupied in the elevation was probably very great; and the work of carrying away the disturbed rock was likewise spread over a very long period, and was exceedingly gradual.

The Wealden beds are interesting as containing the remains of gigantic herbivorous land reptiles, and also of the flying reptiles of the oolite, lias, and chalk.

Wealth (from weal; A.-Sax. welga, rich). In Political Economy, this term denotes such objects and services as are in demand in any community, and which are the products of labour. Natural qualities, as unworked mines or unappropriated forces, are not wealth, except metaphorically. Nor is labour wealth, except it be called effectively into activity by demand. But all products which can be measured by some standard of value are wealth, whether they be material objects, or that kind of labour which either directly or indirectly contributes to the production of objects in demand. Most economists, while they readily acknowledge the claim of material objects to the name of wealth, ignore or deny the right of labour to the title, though they sometimes admit

the phenomena of wealth may dazzle the eyes of those who consider a social state superficially, while the reality is something quite different. For ages the estimate of the riches of Hindustan was exaggerated by the wealth of a few potentates. Later experience has shown that the country is really very poor, for although it contains so many millions of inhabitants as to be nearly ten times as populous as England, the possible revenue which may be extracted from the people is comparatively small; while the capital which may be engaged in industrial pursuits needs, even for the most manifest public advantages, the aid of British savings.

The

Nations do not become wealthy by isolation, nor is the prosperity of a neighbouring country any weakness to another. On the contrary, the growth of foreign wealth is an indirect aid to the developement of prosperity at home. delusion that one nation's gain is another's loss has been the fruitful cause of international jealousy and destructive wars. [POLITICAL ECONOMY.]

Again, the distribution of wealth is as important an object for economical consideration, as its production; for those nations only are permanently prosperous, in which facilities are given for the free developement of wealth among all members of the community. [CAPITAL; DISTRIBUTION; PROFIT.]

Wear or Weir (A.-Sax. wer). A dam in a river, sometimes formed by driving in rows of piles and weaving branches between them, filling up the interstices between the rows with stones.

WEAR. To put a ship on the other tack, by bringing her round with her stern to the wind. [VEER.]

WEATHER

WEATHERING OF ROCKS

Weather (A.-Sax. weder, Ger. wetter). | the developement of electricity; the disturbance The state or condition of the atmosphere, with of the atmosphere produced by the rise and fall respect to heat, cold, dryness, moisture, wind, of the tides; and there may then remain probably rain, snow, fogs, &c. which determine the state of the atmosphere, entirely unacquainted. This very imperfect The various causes many other circumstances with which we are and produce those changes which are in- enumeration may serve to give an idea of the cessantly taking place in its condition, and difficulties to be overcome in forming a theory which are popularly called the weather, form of the weather. [CLIMATE.] the subjects of METEOROLOGY and CLIMATE. [ATMOSPHERE; BAROMETER; CLOUD; DEW; HAIL; HYGROMETRY; RAIN; WIND, &c.]

In all ages of the world, mankind have attempted to explain and prognosticate the changes of the weather; but such is the complication of the subject, and so great the multitude of circumstances to be taken into account, that no theory can furnish rules for determining the order in which they succeed each other, or for predicting the state of the weather at a distant future time with any approach to certainty. Nevertheless, all the different modifications of the atmosphere are the necessary results of principles, not only fixed and unalterable in their nature, but (many of them at least) well known in their separate and individual operation. The difficulty of tracing the results of their combined influences arises chiefly from their complexity and endless concatenation.

The principal cause of all the variations which take place in the state of the atmosphere is the heating action of the sun's rays; but in order to appreciate correctly the effect of this action, we must know not only the extent of the atmosphere, but the properties of all the substances of which it is composed. Modern science has discovered that the atmosphere is composed of three different gaseous fluids, everywhere combined in the same proportions, and penetrated by an ever-varying quantity of elastic vapour. These two distinct envelopes of air and vapour mechanically mixed have different relations to heat; and therefore, in consequence of the unequal temperature of the surface of the earth with which they are in contact, they cannot both be in a state of equilibrium at the same time. Owing to the diurnal rotation, the different parts of the atmosphere are constantly receiving different quantities of heat, as the solar rays penetrate more or less obliquely. This inequality of temperature produces wind, which, if the surface of the earth were perfectly regular and homogeneous, would always blow in the same direction; but as the surface of the earth is composed of materials of various kinds, and irregularly disposed, the distribution of heat over it is extremely irregular. The winds, sweeping along the surface, acquire its temperature; and hence the atmosphere also becomes irregularly heated. This produces an accumulation of air at one place, and a deficiency at another; and hence a subsequent rush to restore the equilibrium. As the air is cooled, it becomes also incapable of holding the same quantity of aqueous vapour, a portion of which is therefore set free, and gives rise to clouds, mist, rain, dew, snow, &c. Besides all this, we have to consider

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the weather is influenced in some mysterious It has always been a favourite prejudice that posed to act on the earth only in one of three manner by the moon. ways; viz. by the solar rays which it reThe moon can be supflects; by its attraction; or by an emanation of some unknown kind. Now, the light of the moon does not amount to 10006 that of the sun; and the heat which it excites is so small as to be altogether inappreciable by the most delicate instruments, or the best devised experiments. With regard to the attraction of the moon, we see its influence on the tides of the ocean, and might therefore be disposed to allow it a similar influence on the atmosphere; but when we take into account the small specific gravity of atmospheric air in comparison with water, and the consequent smallness of the mass of matter to be acted influence also must be extremely feeble. In fact, it has been demonstrated by Laplace, that upon, it will readily be perceived that this the joint action of the solar and lunar attrac tion is incapable of producing more than an atmospheric tide flowing westward at the rate of about four miles a day, and this is scarcely, if at all, appreciable. As to the remaining supposition, that the moon may act on the atmosphere by some obscure emanation, it is sufficient to remark that no meteorological observations that have yet been made afford the slightest traces of any such connection between the earth and its satellite. ters which are now kept in various observatories and other places also prove, contrary to the popular belief, that the changes of weather The regisare in no way whatever dependent on the lunar phases. (Annuaire du Bureau des Longitudes for 1833; Kämptz, Lehrbuch der Meteorologie, and Walker's Translation; Schubler, Einfluss des Mondes auf die Veränderung unserer Atmosphare, Leipzig 1830; Greenwich Meteor. Obs.) which the wind blows. WEATHER. The Sea term for that side on to windward of an object. To weather is to pass

upright, the In Architecture,

feather-edged boarding nailed
Weather Boarding.
boards lapping over each other.
another is said to have the weather gage
Weather Gage. A ship to windward of
of her.

to the BAROMETER; but sometimes also applied
to other instruments for ascertaining the state
Weather Glass. A name commonly given
of the atmosphere, or measuring atmospheric
changes. It is thus applied to the various
forms of the HYGROMETER.

and change of form produced on rocks by the
Weathering of Rocks. The destruction

WEAVERS

action of the weather All rocks are subject to this, and in some countries the effects are much greater than in others. Limestones are thus rendered highly picturesque, for they are acted on by the water in two ways, mechanical and chemical, the water dissolving out the limestone and undermining it; so that falls are frequent. The direct action on many kinds of sandstone is very great, as here also the water penetrates crevices and undermines the rock. On clays the result is yet more considerable.

Cheesewring.

WEBSTERITE

the fabric of cloth is built or darned up, thread by thread, and it is wound up on one of the rollers as it is completed, while a corresponding length of threads is unwound from the other roller in readiness to be transformed into cloth in its turn. In modern looms, the parts are all accurately made of iron and wood, and are so constructed that the process of weaving may be carried on with great rapidity. Apparatus has also been introduced, in some cases of a very complicated character, to enable figures and colours of different kinds to be interwoven in the cloth. But the principle of all existing looms is substantially that of a darning machine.

It

Granite among the crystalline rocks shows remarkable instances of weathering in most countries. The tors of the west of England are some of them very good illustrations. One, called the Cheesewring, near Liskeard, consists In the Indian looms and in the old loom of five blocks, of which the upper are larger than used in this country, the shuttle was thrown the lower, the whole from one side of the web to the other. But, pile being about fifteen about 1740, the fly shuttle was introduced feet high. The stones by John Kay, of Bury. By this contrivance composing this and the shuttle was driven from side to side of the other similar piles suf- web by means of a handle wrought by the fer by the action of the weaver's right hand, while the left gave motion weather most rapidly to a swinging frame. The power loom is driven upon their edges and by steam. The chief peculiarity of the pneuangles, which gradu-matic loom is that the shuttle is shot from side ally become rounded, to side by a blast of compressed air. All reand the blocks then ciprocating looms, however, are defective, and begin to totter and ultimately to fall. This ten- the want now to be supplied is to construct a dency of square blocks to become spheroidal, circular or revolving loom, in which the shuttle, which has sometimes been mistaken for the instead of being driven backward and forward, effect of friction, shows that attrition and trans- should be impelled onward continously. portation by streams are not always essential appears probable that a new form of loom may to their rounded appearance. The celebrated be introduced, in which the operations of the Logging-stone well exhibits the tendency of this sewing machine will be imitated instead of that kind of granite to cuboidal separation. of simple darning; and the practical introduction of circular weaving may be thus promoted. In the stocking loom circular weaving has been already largely introduced. In the Jacquard loom, a chain of perforated cards is made to pass over a drum, and the strings by which the threads of the warp are raised pass over a pulley or edge with a leaden weight of small diameter hanging at the bottom of each. These weights at each stroke of the loom are presented to each successive card, and some of them are intercepted by the card, while others pass through holes in the card, so that by the holes in the card the particular threads of the warp which are raised for the weft to pass through are determined. In this way, the nature of the figure on the cards determines the nature of the figure on the fabic. The Jacquard loom is a modification of the old Damascus loom, in which the fabrics called damasks were first manufactured, with this difference only, that in the Damascus loom the pattern was produced by the skill of the workman, and perforated cards were not employed.

Weavers or Textoria. The name of a tribe of spiders including those which fabricate webs in order to entrap their prey.

Weaving (Ger. weberei ; the word appears in the Greek von, Sansc. vap, a web). An operation by which threads are formed into cloth by a process resembling darning. The loom by which weaving is accomplished is merely an instrument which enables the darning to be performed with a smaller expenditure of time and labour than would otherwise be required. The species of loom at present used by the natives of India is probably its most primitive form. Yet with this rude instrument the most delicate fabrics are produced, and it is mainly by increasing the rapidity of production rather than by improving the quality of the product, that the present generation of weavers has been enabled to excel the ancients in this department of industry. The Indian loom consists substantially of two horizontal rollers of bamboo between which the threads called the warp are stretched. Each alternate thread is raised by being attached by a loop to a vertical string which pulls it up, leaving a space between the layers through which a great wooden needle and thread, or shuttle as we call it, is projected, when the threads before raised are let down and the others raised, so that the same process of transmitting the shuttle may be again repeated. In this way,

Websterite. The native subsulphate of alumina; named in memory of Webster the geologist. It occurs in white or yellowishwhite reniform masses and botryoidal concre tions, in a layer of ochreous clay, in the cliffs at Newhaven on the coast of Sussex, and in potholes in the chalk near Hove in the same county.

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