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the ground (c); and the anchor, if pulled in the direction of the shank, has a tendency to fix itself more firmly in the ground, by keeping the

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lower fluke almost perpendicular in the ground. Captain Denham, of the Marine Surveyor's Department at Fleetwood, gave a report of some experiments which he had tried in 1840 on the new swivel anchor, and states the following as the results to which he had arrived:-"It is almost impossible to foul it; it bites quickly into the most stubborn ground; it holds on to the shortest stay-peak; it cannot lodge on its stock end; it presents no upper fluke to injure the vessel herself, or others, in shoal water; it cannot injure vessels' bows when hanging acock-bill, as merchant-vessels find a convenient practice; it is not so likely to break off an arm, or part in the shank, as anchors with fixed flukes do, because the construction of these arms can be of continuous rod-iron, and the fulcrum of leverage is so much nearer the ring, owing to the pea of the upper fluke closing upon the shank; it is a most convenient anchor for stowing inboard on a voyage, as the flukes can be easily separated and passed into the hold; it can as easily be transported by two boats when one would be distressed by the whole weight; it produces the desired effect of ground-tackle at onetwentieth less weight." (Unit. Serv. Journ.,' March 1840.)

Mr. Porter's anchor has been the basis on which improved forms have been introduced by Trotman, Honiball, and other inventors. Trotman's construction, patented in 1852, differs from Porter's chiefly in these points that the palms are fixed intermediately on the breadth of the arm, instead of in front; and that the horn is of greater width than the arm, for a different shape is also given by Trotman to the upper part of the palm, in order that, as the tension of the cable buries the palm deeper into the ground, the upper flap of the palm being turned over so as to form the spur or horn, admits of the clay or sand, or mud being easily delivered' like the soil from a ploughshare. Hence it is often seen at anchorages which dry at low water, that Trotman's anchor buries itself totally some feet below the surface (a valuable consideration when a ship is riding heavily on a lee-shore!) while its shape insures ready extrication when the cable is hove full 'stay a peak:' for its ploughing qualification is available in any direction. As regards originality, a notable legal decision was arrived at in 1855. Mr. Porter took out his patent in 1838; and an extension of the patent right was obtained in 1852; but this extension underwent a sudden check. During an action for infringement of patent, in 1855, it was proved that Porter's anchor was not a new one within the terms of the letters patent. Many years antecedent to 1838, Mr. James Logan had invented and made public the contrivance of a swivel anchor; he exhibited drawings and models; nay, he made such an anchor in 1826 for a steamer named the 'William Huskisson. These facts were not known to Mr. Porter in 1838; but they vitiated his patent. Accordingly, in 1855, Mr. Pemberton Leigh, on the part of the Judicial Committee of the Privy Council, pro

nounced Porter's patent to be null and void, and the invention therefore open to the free use of any one.

In July, 1852, a trial of anchors was made at Sheerness, by order of the Admiralty. Those selected were to be bower anchors of 25 cwt.; and they were to be tested with regard to the following qualities;"strength; holding, particularly when at a short stay, and being obliged to make sail; weight, and facility for stowing; quick holding; sweeping; tripping; fouling," &c. There were four modes of testing devised, in relation to the kind of ground chosen. The anchorsmiths of all nations were invited to compete, and several competitors appeared. The experiments occupied many days, and two or three of the anchors performed admirably. The most efficient appeared to be Porter's under the improved form introduced by Trotman.

Many patents for anchors have been obtained within the last few years such as Firmin's in 1854; Scott's in 1855, and Hunter's in 1856; but they related chiefly to slight modifications of constructions already in use.

The number of anchors carried at both the bows and stern of a ship have been finally reduced to four principal, and these all at the bows. The anchors supplied to men-of-war are the best and small 'bowers,' the 'sheet,' and the 'spare:' these are of the largest size; to which are added, the 'stream' and the 'kedge,' which are used for particular or for temporary purposes, and are usually carried 'in board.' Since there is but small difference in the form of anchors of different weights, the stream of a large vessel serves for the bower of a smaller. Various rules have been given for the dimensions of anchors. The rough rule in the navy is, 1 cwt. to a gun; thus, an 80-gun ship will have an anchor of 80 cwt.; and a merchantman of 200 tons having an anchor 10 cwt., 5 cwt. is added afterwards for every 100 tons: thus 300 tons would give 15 cwt., and so on. The principal dimensions of the anchors in the navy may be stated shortly thus: calling the shank 10, the arm is about 3, the breadth and depth of the palm about half this, the thickness or depth at the small, 42, at the throat 6, which are nearly the dimensions of the arms also, and the breadths about of these, the edges being rounded. The weight of an anchor of 10 feet in length is, according to Pering, about 114 cwt., and since, if the forms of all anchors were alike, the weights would be as the cubes of the lengths, the weight of any anchor might be found (nearly) by multiplying the cube of its length by 0114. The recent improvements in anchors are however likely to derange the old rules in respect both to the dimensions and weights of the several parts.

The largest anchors ever yet employed were those adopted by Mr. Brunel in the launching of the Great Eastern,' or 'Leviathan,' in the winter of 1857-8. They were required, for the enormous strain incident to that operation, to bear a breaking test of 110 cwt. each; and the chain cables for them, by Messrs. Brown and Lenox, were the largest ever made.

In the technical employment of anchors on board ship, an anchor is said to be 'foul' when the cable is any way entangled with it; to 'come home,' when the ship drags it; to be a-wash,' when the stock is hove up to the surface of the water; to be 'acock-bill' when hanging vertically; and to be 'stay a peak' when just ready to lift from the ground.

A'NCHORET, sometimes written, and more correctly, Anachoret, a Greek word (avaxwpnrns), signifying a person who has retired from the world. Under Christianity they sprung up about the middle of the 3rd century in Egypt and Syria, where many believers went to hide themselves in caves and solitary wilds, from the fury of the persecution which arose under the Emperor Decius. Paul, commonly called the hermit, has the credit of having been the first regular anchoret. A distinction, however, came afterwards to be drawn between anchorets and hermits: the former name being given only to those who rigidly confined themselves to their caves or cells; and the latter to those who, although they had broken off all commerce with the world, still wandered about at large in the wilds to which they had retired. Both descriptions of recluse were entirely distinguished from the Cœnobites, or those living in communities. Many of the anchorets were laymen; and there were also female as well as male anchorets. From nearly the commencement of the 7th century, the Church assumed a jurisdiction over anchorets; and persons were not allowed to enter upon the mode of life in question, except by permission of their ecclesiastical superiors, and after an appointed ceremony had been performed, at which the bishop presided. Churches and religious houses in the middle ages would sometimes keep an anchoret shut up in a cell, which was usually attached to the choir of the church. attraction brought great crowds of the devout and the curious to the holy place, which benefited much by their offerings. It was eventually found necessary, in our own as well as in other countries, to lay down certain regulations with a view of discouraging the adoption of this solitary life. The most singular species of anchorets recorded in the history of the Church, is that which arose in Syria in the 5th century, and of which Simeon Stylites was the founder. This zealot and his followers, instead of resorting, according to the customary fashion, to caves, elevated themselves into the air, on lofty pillars of stone, on the tops of which they passed their lives. They have hence received the names of pillar saints, holy birds, and aërial martyrs.

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ANCHUSIC ACID (C,,H2O,?).-(Anchusin.)-A resinoid colouring matter obtained from Alkanet root (Anchusa Tinctoa). It is inso

oil.

luble in water, but soluble in alcohol, ether, and oils, to which it
imparts a fine carmaine red colour. It is hence used for colouring hair-
Its alcoholic solution is bleached by exposure to light.
ANCHUSIN. [ANCHUSIC ACID].
ANCHYLO'SIS, a Greek word (dykúλwois), signifying a bending. If
the Greek orthography were strictly followed, the word would be written
ankylosis.

no little confusion. The Eastern Roman empire, for instance, survived
the Western by many centuries; nor can any good reason be given
why the subjects of Justinian and his predecessors should be classed
among the ancients, and those of his successors among the moderns.
If the question were asked, where should a Greek author in a late
period of the Eastern empire be placed, we could not call him either an
ancient or modern Greek writer without giving cause for considerable
misapprehension. The use of the term medieval may, however, to a
certain extent remove the difficulty-at least in many cases.
In the
case of the Oriental nations, the terms ancient and modern are still
applied, and often perhaps with no very distinct notion of their
import, even by those who employ them. We hear commonly of
ancient and modern Persia, ancient and modern India. Now, in the
case of the Persian empire, in seeking for a date, we might choose
between the conquests of Alexander the Great, the irruption of the
Parthians, the restoration, as it is called, of the old Persian dynasty,
and its subjugation by the Mohammedans. Any one of these events,
and especially the last, would furnish perhaps better ground for the
distinction of ancient and modern Persia, than anything which occurred
at the time of the overthrow of the Roman empire.

It might be expected that the convenience of having at hand such terms as ancient and modern would often lead to some abuse, and this is particularly observable in the vague reference so frequently made to "the ancients." There is no definition which excludes from their number any who lived from the time of Noah down to the last Roman emperor; and it is obvious, that there is not much which can be safely predicated of a class so large and comprehensive; yet we often hear of what "the ancients" said, and did, and thought. Allusion is made to the military tactics or the philosophy of the ancients: comparisons are are told of the sentiments on certain subjects entertained by the heathen ancients. The truth is that, by "the ancients," we must understand, on many of these occasions, Greeks or Romans at certain periods of their national history; and even thus limited, there are few assertions which will hold good of "the ancients" generally. For the most part, perhaps, the looseness of the expression is corrected and limited by the subject or the context; but it is also true, that real misapprehension has arisen from the practice of throwing together and confounding the most dissimilar things by the help of this comprehensive term.

An essential part of the apparatus of locomotion in animals consists of the structure termed a joint. [JOINT.] Joints are so constructed as to produce various kinds and degrees of motion, in the execution of which it is necessary that the different parts constituting the joint should be in close contact with each other. Organised living surfaces, in close contact with each other, have a tendency to grow together; but such a union would at once destroy the action of a joint, and a specific apparatus is provided for the express purpose of preventing this event. What are termed articular surfaces, that is, the surfaces of joints, are covered with a thin and delicate membrane which secretes a peculiar fluid of an unctuous or oily nature, termed synovia. This synovia, the oil of joints, is in general effectual in keeping separate and distinct the different parts of the joint, however closely and for however long a time they may be in contact with each other; nevertheless, it does occasionally happen that a firm and complete union takes place between the different articular surfaces: when this occurs, it constitutes what is technically termed anchylosis, or, in common language, a stiff joint. An anchylosis, or a stiff joint, consists then of the immoveable union of two bones naturally connected together in such a manner as to form a moveable joint. All the moveable bones forming joints may become consolidated together, or anchylosed; and cases are on record of a general anchylosis of all the bones of the human body. Whatever keeps a joint motionless for a long time together may give rise to anchy-instituted between the literature of the ancients and moderns; and we losis. Hence it is apt to occur after the fracture of a bone in the neighbourhood of a joint; because it is necessary to the cure of the fracture that the limb should be fixed in one position, while the inflammation occasioned by the violence that produces the fracture often spreads to the joint, and it is one of the ordinary effects of inflammation to agglutinate and consolidate the parts inflamed. Hence inflammation, sprains, dislocation, shocks occasioned by leaping or falling on the feet from great heights, ulcers, are the common causes of anchylosis. But anchylosis cannot always be considered in the light of a disease; at any rate, it is sometimes the happy termination of a formidable malady. The natural cure of many painful and dangerous diseases of the joints is the formation of an anchylosis. When an anchylosis is forming, and is clearly inevitable, and is indeed a thing to be desired, the position in which the limb is kept, or the position in which the bones are allowed to unite, is a matter of great importance to the future comfort of the individual. When, for example, from injury done to the hand, the joints of the fingers are undergoing the process of anchylosis, it is very important to keep the fingers bent, because, if they anchylose in that position, the hand will be more useful than it could be were the fingers permanently extended. On the contrary, when there is danger of anchylosis of the knee-joint, the limb should be kept as straight as possible, because, if the leg be extended, the limb will be more useful than if it were permanently bent. On the other hand, when anchylosis of the elbow-joint cannot be prevented, the limb should be kept bent. The term anchylosis is also employed to denote a natural union of bones. Thus, bones, or parts of bones, which are separate in the early stages of their growth, and afterwards become united, are said to be anchylosed. Also in the case of animals belonging to different divisions of the animal kingdom, bones which remain separate in one class through life, are found united in another class, and anchylosis is said to have taken place.

ANCIENT, ANCIENTS. The term ancient, which we derive from the French word ancien, has the primary meaning of "very old," as when we say 66 an ancient building," "an ancient family," implying only that many generations have passed since they first came into existence. But it is also used in a more limited sense, with reference to a certain period in the existence of the human race: as when we speak of ancient, as distinguished from modern, history; of the ancient classics, ancient literature, and generally, of the ancients. The boundary line between ancient and modern in this latter sense is not very accurately drawn; but according to the common acceptation of the terms, the period of the ancients seems to be closed by the final and complete overthrow of the Western Roman empire. With reference to the nations over which that empire extended, the distinction is not altogether arbitrary, or without an intelligible reason. The overthrow of the Roman empire marks the commencement of a new order of things, when we begin to discover the rudiments of those powerful independent nations, of those various languages and peculiar institutions, which so remarkably distinguish a large portion of what is called modern Europe, from Europe under Roman dominion. There is of course a short interval, which may be considered as doubtful ground, for the possession of which the terms ancient and modern will always be allowed to contend.

It is plain that the reason here given for the commonly received distinction is applicable only to the West and South of Europe; yet the same distinguishing terms are familiarly used, and in many cases the same date arbitrarily assumed with reference to the rest of the world. This practice is attended with many difficulties, and produces

This is not the place to enter on the consideration of ancient and modern history; but there is an evil in some measure connected with the use of these terms, which it may be worth while to notice. It is to be feared that the common division of the subject of history into two parts, ancient and modern, too often conveys the notion of an actual separation which does not exist. The young student pictures to himself a great gulf between them. When busy with the ancient part of the subject, he imagines himself to be conversing with beings of a different nature from himself. He believes the narrative, but is affected by it much as he would be by a work of fiction. When he has crossed the gulf, and passed from the obscure regions of ancient history into the stronger realities of modern times, he converses freely with beings of the same flesh and blood with himself. It is not requisite to enumerate all the bad effects which must arise from this impression. It is evil enough that the student must necessarily overlook the important fact, that the subjects of what are called ancient and modern history are so far one and indivisible, that a comprehensive view of the ancient part is necessary for the profitable study of the modern. ANCIENT DEMESNE. [MANOR; SOCAGE.] ANCIENT LIGHTS. [LIGHTS.]

ANDAN'TE, in music, is the third in order of the five classes into which musical movement is divided [ALLEGRO], and the medium between the extremes of slow and quick.

The music of Corelli, Handel, and their contemporaries, was generally much slower than that which prevails at present, and Andante was then used to denote a moderate degree of quickness: now it indicates a steady, calm movement, rather inclining to slowness than the reverse. It also enjoins a more than ordinary attention to the measure, to the equality of time given to each bar. This term is also used substantively: thus we say, 'an Andante of Haydn,' &c

ANDANTI'NO, in music, is the diminutive of 'andante.' It affords a curious example of the vagueness of musical terms, that musicians are not agreed whether this diminutive ought to mean 'less slow,' or less quick.' When the word andante is used, as by the old masters, to denote a degree of quickness, its diminutive abates its motion: when employed to indicate a movement rather slow than quick, as in the present day, the diminutive increases its motion. For want of adverting to this fact, much misapprehension and some disputes have arisen. It, however, seems to be agreed, that andantino now shall signify a movement quicker than andante-that it shall be the medium between the latter and allegretto.

ANDRO'MEDA, a constellation, so called by the Greeks from Andromeda, the mythological daughter of Cepheus and Cassiopeia, who was bound to a rock and thus exposed to a sea-monster, from whom she was delivered by Perseus. This constellation occupies a considerable region of the heavens below Cassiopeia, by which it may be thus found. A line drawn through the brightest star of the five in Cassiopeia, marked B, and the pole star, passes through a star of the

first magnitude in the head of Andromeda, marked a, and called Alpherat. A line drawn through e Ca siopeia, at the other corner, and the pole star, passes through Almach in the foot of Andromeda, marked y, while in the line between the two stars thus found, lies Mirach, marked 8, in the girdle of Andromeda.

The following is an enumeration of the principal stars in this constellation, classified according to their magnitudes:

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climates, a saturated brine which does not freeze should be substi tuted for the water; its specific gravity is 1.244, so that the force given by the table must be multiplied by this factor.

The following table, calculated by Dr. Hutton, and given in his 'Mathematical Dictionary,' is based upon some experiments made with Dr. Lind's anemometer, at Woolwich; it may be used with that instrument, and indicates what velocity of wind corresponds to various differences between the levels of the liquid, and the consequent force Number of Stars. of the wind. Thus, when the column of liquid is 9 inches, the velocity is 108 miles per hour, and the pressure on the square foot is 43.9 lbs., producing a most violent hurricane; so that in the greatest storms the difference between the atmospheric pressures on the windward and leeward sides of any object does not amount to th of the pressure on the leeward side, which, we know, is capable of supporting a column of water 32 feet, or of mercury 30 inches.

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45

Hence the total number of the stars in this constellation which are visible to the naked eye amounts to 63.

The following are the designations of the various stars in Andromeda, down to the 4th magnitude inclusive:

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ANEMO'METER (from reuos, the wind, and uerpéw, to measure), is an instrument for measuring the force of the wind, by finding what mechanical effect the wind to be measured will produce upon the apparatus. The first anemometer seems to have been invented by Dr. Croune, in 1667, but this did not answer its purpose well, and a better instrument was devised in the last century by Wolfius, which is described by him in his 'Elementa Matheseos,' vol. ii. p. 319 (Geneva edition, 1746). It consists of four sails, similar to those of a windmill, but smaller, turning on an axis. On the axis is a perpetual screw, which turns a vertical cog-wheel round a second axis, placed transversely to the former. To the second axis is attached a bar, on which a weight is fixed, so that the sails cannot turn without moving round the bar in a vertical circle. When the wind acts upon the sails the bar rises, and this continues until the increased leverage of the weight furnishes a counterpoise to the moving force of the wind. The number of degrees the bar moves through to produce this effect is measured on a dial, the hand of which turns on the axis of the cog-wheel.

Another form of anemometer was invented by Leslie, depending for its action upon the principle, that the cooling power of a current of air varies as its velocity. Another instrument depended on the evaporation of water, which, for any time, is proportional to the velocity of the wind. In all these forms, however, the force is measured either by the compression of a spring, or by the raising of some weight to a height varying with the force to be measured. The former method, though more convenient, is, owing to the diminution in elasticity by frequent compression, liable to give varying results. The principle of Dr. Lind's anemometer is as follows:-A, a curved tube of glass, as represented in figure 1, is Fig. 1. partially filled with water. The bore of the tube is diminished at the bottom, as a check on the oscillations to which, the water is subject from sudden variations in the force of the wind. The wind acts upon the open end A, and depresses the water to B, until the column of water b C, the difference between the levels B and C, is a counterpoise to the force of the wind on B. This difference can be ascertained by the graduated scale. Hence, when the area of the bore at B is known, and the height of b C observed, the found the weight of which is equivalent to the The velocity may thence be found by observing

B

C

b

column of water is force of the wind.

Fig. 2.

(AERODYNAMICS) that the velocities are nearly
as the square roots of the resistances, and that
the moving force of a wind of 20 feet per
second on a square foot is 12 ounces.

Lind's anemometer has been improved by Sir W. Snow Harris, who has reduced one of the limbs to the diameter of one-fourth of the tube which is open to the wind, and by making the first part of the scale horizontal the delicacy of the instrument has been much increased. He has also provided it with a plumb line, and with a light vane to facilitate the operation of observing. (See fig. 2.) Sir John Herschel, in the Manual of Scientific Inquiry,' recommends that in using this instrument in cold

In Regnier's anemometer, a bar, carrying a flat wooden surface at right angles to it, protrudes from a box, through a hole in the front of which it slides. This bar is met by a spring, which resists its further entry, until force is applied against the wooden surface. In the interior of the box, the under side of the bar carries rackwork, which plays on a cog wheel, the axis of which, passing through a side of the box, carries a hand round a dial-plate. The flat surface of wood is presented to the wind, which presses upon it and forces back the bar, carrying the cog wheel and hand through an angle, greater or less, according to the greater or less impulse of the wind.

Various other contrivances have been proposed, the most important

of which are by Dr. Whewell and Mr. Osler. In Whewell's anemometer (fig. 3) a windmill fly is, by the action of a vane, constantly presented to the wind, and the velocity of the revolutions of the fly

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ANEMO'METER.

over a fixed cylinder, producing thereon a trace of variable length,
according as the wind varies in velocity. The surface of the fixed
cylinder is divided into sixteen or thirty-two equal parts by means of
vertical lines, the spaces between which correspond with the points of
the compass, and between or upon these divisions the pencil is moved
about by means of the vane, and the trace that it leaves shows the
direction of the wind. The pencil, however, has two motions, one
from above, downwards (10,000 revolutions of the fly causing the pencil
to descend of an inch), and this motion increases as the wind blows
more strongly, and by the extent of its depression registers the whole
amount of wind that has been blowing. The other motion depends on
changes of the quarter from which the wind blows; the pencil and its
frame are carried round by the vane, so as to register the direction of
the wind. Thus, if the fly revolve in the simple proportion of the
velocity of the wind, the trace marked by the pencil describes a space
proportional to that which a particle of air would describe in a given
direction in a given time, taking into account the strength of the wind
and the time for which it blows. The constant wavering of the wind
causes the pencil to describe, not a single line, but an irregular broad
path, something like the shadings in the coast of a map. The middle
of this line will give the mean direction of the wind, while its length
will be in proportion to the product of the velocity of the wind and
the length of time during which it blows in each direction, which
product is called its integral force.

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fig. 5), and driving a cog-wheel, which rolling on a fixed cogged circle,
Fig. 5.
turns the rest of the apparatus round, so as to present the edges of the

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A great objection to the above form of anemometer is the amount of friction involved in the method of converting the rapid motion of the fly into a slow descending motion, and in the mode by which the pencil is made to move against the fixed cylinder. Osler's anemometer has some advantages over Whewell's. This instrument traces the direction of the wind and its pressure on a given area, together with the amount of rain, on a register sheet divided into twenty-four portions, corresponding with the twenty-four hours of the day. The action of this instrument will be understood by referring to fig. 4,

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under these circumstances, the pressure-plate is placed at right angles
sails to the current when it is no longer turned by it either way:
to the vanes, and is acted on with full effect by the wind. As the
vane or cap turns in the direction of the wind, a spiral worm on the
shaft near its lower end raises or lowers the fixed nut I, from which
springs the arm which carries the pencil в; this pencil traces a mark
on one of the long lines of the register when the wind is blowing from
one of the cardinal points, or between those lines, if it be blowing from
intermediate points. The pressure-plate E is made to face the wind by
It is suspended by means of four springs,
means of the vane or cap.
which yield to gentle winds, while a stronger spring receives the more
violent pressure of a high wind. The motion of the plate is trans-
mitted to the register-paper by means of a wire connected by the
bell-crank J with another wire, which descends through the hollow
upright shaft, and is kept stretched by a spiral spring. This wire
carries the upper pencil c, which of course descends lower in propor-
tion as the pressure-plate E is pushed back, and returns to the top of
In this way, the distance to
the paper when the pressure ceases.
which the pencil is depressed shows, by means of a number of
irregular parallel lines, the pressure of the wind in pounds on the area
of one square foot, or its velocity in miles per hour. For registering
the rain, the pencil A is attached to a lever AF, fig. 4, which is moved
by the following contrivance: A rain-receiver, D, is placed on the roof
of the house, and the water which pours into it is conducted into one
of the two divisions of a gauge, GH, balanced on an axis and supported
by a second balance: as the water accumulates in G (for example), the
second balance begins to descend, and thus raises the upright rod to
which the lever FA is attached, when the pencil, being raised with it,
makes a mark on the paper, which represents the quantity of water
collected in the gauge. When this quantity is equal to a certain
depth of rain or to a certain number of cubic inches on a square foot,
the gauge becomes upset by the weight of water, the water is thrown
out, and the other compartment, H, is brought under the pipe; the
effect of which motion is to send the pencil to the bottom of the paper,
and it only begins to rise again when more rain is collected. Of course,
the heavier the rain, the sharper will be the angles formed by the
trace of the paper; whereas, if the rain be gentle, the elevating or
diagonal lines will be drawn out to a considerable length; and lastly,
if there be no rain, the pencil will trace a horizontal line, such as is
represented in fig. 4, from vi. to VIII, and from x to I.

Thus it will be seen, that as the register-paper is being constantly moved forwards by the action of a clock, the three pencils mark the direction and pressure of the wind, together with the amount of rain. which represents the parts adjoining the register-paper. The central The register-paper may be ruled for twenty-four hours, or for a week, portion of this paper has a series of lines corresponding with the and it may be placed vertically, as at the Royal Exchange, London, or cardinal points of the compass, for indicating the direction of the wind. laid horizontally on a table, as at the Meteorological Observatory at The upper part of the paper has a series of lines corresponding with Greenwich, where the register, being on a larger scale, is changed the pressure in pounds on the square foot, while the lower part of the every day. Mr. Osler has further improved his anemometer in the paper has a series of lines corresponding with given quantities of rain. following manner: A sheet of plain paper, placed in the instrument There is also a series of twenty-four vertical lines, corresponding with under a registering pencil, is moved forward by rotating hemispherical the twenty-four hours of the day, so that a new register-paper, being fans, at the rate of one inch for every two miles of air that passes; properly placed on a board, is carried along upon friction-rollers, by this same pencil, having a lateral motion given to it by a vane, records means of a clock, behind the three pencils A, B, C, which may be the point of the compass from which the wind blows; and a clockregarded as the indexes of the machine. The pencil B, which marks hammer descending every hour, strikes its mark on the margin of the the direction, is operated on by means of a set of vanes (fig. 5), turn-paper to express the time. Thus in a single line are given, 1st, the ing vertically in a plane at right angles to that of the pressure-plate (E, length of the current; 2nd, the direction of the current; 3rd, the

time occupied in passing a given station marked hourly, or at any shorter interval that may be desired.

The Rev. W. Foster, of Sturbington, near Portsmouth, has contrived an ingenious anemometer, which is fully described in Sir W. Snow Harris's Report on the Working of Whewell's and Osler's Anemometers at Plymouth during the years 1841,-42,-43,' presented to the British Association for the Advancement of Science in 1844, to which we are indebted for some of the preceding details. Foster's anemometer consists of a cross horizontal fly three feet in diameter, with four vanes each six inches square, and so contrived as to revolve in one direction only. The revolution of this fly imparts motion to a vertical shaft, at the lower end of which is an endless screw, which is connected with a train of wheels to a disc, twenty-two inches in diameter, which is caused to revolve slowly in a horizontal plane, and this disc thus registers the revolutions of the fly, which may be in any convenient proportion to those of the disc.

By means of a second vane and a vane-rod a second disc, nine inches in diameter, is made to revolve. There is also a rain-receiver on the roof, and a pipe by which the rain descends into a balanced gauge, the reciprocating motion of which causes an axis to work in a toothed wheel under the disc, through a space proportional to the quantity of rain delivered at each tip of the gauge. There is also a rod set on friction-rollers, and furnished with a rack adapted to the tooth of a horizontal rod projecting from the centre of a clock. There are twenty-four teeth in the rack, so that the rod is moved hourly one division, by which motion three pencils are hourly moved upon the respective discs, so that traces are obtained of the direction and velocity of the wind, and of the rain for every hour.

We give the following table as a specimen of the interesting results of the operation of this instrument. It shows the total and mean hourly velocity of each wind in miles.

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Professor John Phillips had, in the Great Exhibition of 1851, an anemometer for collieries, hospitals, &c., for ascertaining the velocity of the current in the ventilation of such places. The pressure is received on a semicircular disc of cardboard, suspended by the diameter and measured on a graduated arc. By tables calculated from the equation, sin. 0 vel. = the velocity is obtained in terms of the angle. Cos. 20' M. de Hannault also exhibited a small travelling anemometer, consisting of a series of fans which, by a simple contrivance, could be stopped or set in motion almost momentarily. Its chief object was to determine the horizontal velocity of the air in a given time.

M

In the anemometer erected at Kew Observatory Dr. Robinson's method is adopted, namely, that of measuring the velocity of the wind by the rotation of a system of hemispherical cups, the direction being indicated by a double-wheel fan, like the directing vane at the back of a windmill. A stout tubular support carries the whole of the external part of the instrument, including the measurer of velocity, the direction vane, and a rain gauge. All the rotatory parts of the anemometer run upon friction-balls. The shaft of the apparatus for measuring the movement of the wind by means of a diminishing train of wheels, is made to turn a cylinder upon which is wrapped a sheet of paper of the kind used for metallic memorandum-books, which paper receives a trace from a brass style. The sheet of paper is divided into two sections, upon one of which is recorded the motion of the wind, and upon the other the direction. As the cylinder is being turned by the action of the wind, a clock carries a pencil along the cylinder at the uniform rate of twelve inches in twenty-four hours. To the lower end of the direction-shaft is attached a spiral of such a figure that equal angles correspond to equal increments of radius; the edge of this spiral consists of a thin slip of brass, which touches the paper and records the direction of the wind on a rectilinear scale. When the sheet of paper is taken off the cylinder after the lapse of twenty-four hours, the motion of the wind and the direction are both found projected in rectangular co-ordinates. This self-registering apparatus was designed and constructed by Mr. R. Beckley, assistant in the observatory.

In a letter to the writer of this article Mr. Beckley remarks:-"The principal improvement I think, consists in the method of mounting, by the application of the hollow shaft to the direction vanes; as in all cases where the cups have been used the velocity and direction of the wind have been two distinct erections, whereas all that is necessary in my case is a base to bolt the column upon. I also economise space within the building. The method of registration consists in using metallic paper, upon which brass becomes a pencil; the form of which is a very thin-threaded screw, whose pitch, in the case of the velocity-pencil, is equal to a scale of fifty miles upon the paper. By this means I get a very open scale in a small space. The pitch of the direction-screw is equal to any openness of scale that is desirable. By using this form of pencil I ovecrome the difficulty attending the old method, namely, the pencil shifting off the scale, to obviate which, it was usual to have three sets of scales upon the paper; but even then, should the wind go twice round in the same direction, it ceased to indicate, whereas in my arrangement it must at all times register."

With respect to anemometric observations at sea, Mr. Welsh, Director of the Kew Observatory, gives the following method of making allowance for the effect of the ship's motion upon the observed velocity and direction of the wind:-"By means of a portable Robinson's anemometer, provided with a means of observing the total number of turns made by the rotating part in any given time, observe the apparent velocity of the wind, and record it in knots per hour. By an anemoscope of any kind register the apparent direction of the wind. From the log-book take the rate and direction of the ship's motion. On a slate or other similar surface scratch a permanent compass circle: set off from the centre of the circle, on the radius of the direction of the ship's head, by any convenient scale, the number of knots per hour the ship is going; from this point draw a pencil line parallel to the direction of the wind as observed by the anemoscope (that is, the apparent direction to which the wind is going); set off on this line the number of knots per hour as shown by the anemometer; draw a line from the centre of the circle to this last point. The length of this line by the scale adopted, gives the true velocity of the wind, and its direction (carried backwards) shows the point from which the wind is coming. A parallel ruler divided on the edge is all that is required besides the slate. It would be easy enough to contrive some mechanism to save the trouble of drawing lines, but it would not, I believe, be any real simplification, and would increase the expense. The train of indicating wheels might be so arranged that they at once indicate knots per hour, without reference to tables, and can be readily set to zero for a fresh observation." ( British Association Report,' 1856.) Professor C. Piazzi Smyth, from a series of observations communicated to him by Captain H. Toynbee, concluded that the only unexceptionable station for anemometrical observations at sea was the mast-head. He had therefore contrived an apparatus for measuring the direction and the velocity of the wind, arranged with a view to such a position, and also with a view to observe accurately the mean effects, and this by a summation of every individual gust, even the lightest. For the most accurate plan of securing data, he had arranged a method of electric registration, which was carried on in the cabins below, while the anemometers were measuring the wind aloft. ('British Association Report,' 1855.)

anemometers, see AERO-DYNAMICS. For the method of discussing the results obtained by means of

ANEMONIC ACID. A name given to two distinct acids derived from the Anemone Pulsatilla, A. Pratensis, and A. Nemorosa. One of these acids has the formula CHO... The formula of the other is doubtful. Neither acid possesses any especial interest.

ANEMONIN (C30H12012?). A white crystalline body found in the water distilled from the Anemone Pulsatilla, A. Pratensis, and A. Nemorosa. It is poisonous, and slightly irritating to the skin. Alkalies transform it into anemonic acid.

ANE'MOSCOPE, an instrument for determining the direction of the wind; usually constructed by connecting with the spindle of a weathercock the hand of a dial on which the points of the compass are marked. [ANEMOMETER.]

ANEROID BAROMETER. [BAROMETER.]

ANE THUM GRAVEOLENS (DILL)-Medical Properties of. This is an umbelliferous plant, native of the south of Europe, Astrakhan, Egypt, and the Cape of Good Hope: it has either migrated or been introduced into Egypt and the Cape. It is also cultivated in England. It was in high repute among the ancients, both as a medicinal and a savoury herb, being mentioned by Hippocrates and Dioscorides (ǎvnov of the latter); also in the Bible (Matt. xxiii. 23), where, however, it is translated anise. The fruit is the part which is officinal. This consists of a diachenium formed of two flattened mericarps, on the back of which is one, and on the commissure two vittæ, containing the volatile oil, on the presence and quantity of which the peculiar odour and virtues of the fruit depend. The quantity of oil varies much according to the degree of ripeness, the age, and, above all, the place of growth of the fruit. Fruits too ripe, or very long kept, yield less than those gathered before perfect maturity, or very fresh ones. Those raised in England are inferior to those from the south of Europe; the clearer and drier atmosphere of the latter favouring the elaboration of volatile oils. To obtain it, the bruised fruit is submitted to distillation with water: 2 cwt. of good fruits yield 8lbs. 5 oz. of oil. (Pereira.) The

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