architectural and sculptural enrichments generally; in the enrichment of modillions, of mouldings, and of vases, as well as of foliated capitals; and we gather from Virgil, that the acanthus was by the ancients also employed as an ornament in embroidery. In the first book of the Æneid,' verse 649, and again at 711, a veil or vest is said to be interwoven or embroidered with the crocus-coloured or saffron acanthus. Pliny the elder, in his 'Natural History,' describes the acanthus in such a manner that it can only be recognised in the brank-ursine; and his nephew, in speaking of the successful cultivation of the same plant as an ornament to his garden, leaves little doubt that the brank-ursine is identical with the common architectural and sculptural acanthus. It is stated, however, that the brank-ursine (Acanthus mollis) does not grow in Greece, and it has been suggested that the plant from which the Greek architectural ornament was taken was the Acanthus spinosa, which grows there, and is still called the ǎkavoα.

This ornament, in the ancient Greek and Roman models, is very characteristic of the styles of architectural enrichment of those nations; in the Roman it is full, and somewhat luxuriant, and in the Greek more restrained, but simple and graceful.

ACCELERATED MOTION, ACCELERATING FORCE, ACCELERATION. When the velocity of a moving body is continually increased, so that the lengths described in successive equal portions of time are greater and greater, the motion is said to be accelerated, which is the same thing as saying that the velocity continually increases. [VELOCITY.] We see instances of this in the fall of a stone to the earth, in the motion of a comet or planet as it approaches the sun, and also in the ebb of the tide. As it is certain that matter, if left to itself, would neither accelerate nor retard any motion impressed upon it, we must look for the cause of acceleration in something external to matter. This cause is called the accelerating force. [See INERTIA; FORCE; CAUSE to the remarks in the last of which articles we particularly refer the reader, both now and whenever the word cause is mentioned.] At present, the only accelerating force which we shall consider is the action of the earth, producing what is called weight, when not allowed to produce motion.

It is observed, that when a body falls to the ground from a height above it, the motion is uniformly accelerated; that is, whatever velocity it moves with at the end of the first second, it has half as much again at the end of a second and a half; twice as much at the end of two seconds; and so on. At least this is so nearly true, that any small departure from it may be attributed entirely to the resistance of the air, which we know from experience must produce some such effect. And this is the same with every body, whatever may be the substance of which it is composed, as is proved by the well-known experiment of the guinea and the feather, which fall to the bottom of an exhausted receiver in the same time. The velocity thus acquired in one second is called the measure of the accelerating force. On the earth it is about 32 feet 2 inches per second. If we could take the same body to the surface of another planet, and if we found that it there acquired 40 feet of velocity in the first second, we should say that the accelerating force of the earth was to that of the planet in the proportion of 32 to 40. By saying that the velocity is 324 feet at the end of the first second, we do not mean that the body falls through 32 feet in that second, but only that if the cause of acceleration were suddenly to cease at the end of one second, the body would continue moving at that rate. In truth, it falls through only half that length, or 167, in the first second. It may be proved mathematically, that if a body, setting out from a state of rest, have its velocity uniformly accelerated, it will, at the end of any time, have gone only half the length which it would have gone through had it moved, from the beginning of the time, with the velocity which it has acquired at the end of it. Thus, if a body have been falling from a state of rest during ten seconds (the resistance of the air having been removed), it will then have a velocity of 32 x 10 or 321 feet per second. Had it moved through the whole ten seconds with this velocity, it would have passed over 321 x 10 or 3216 feet. It really has described only the half, or 1608 feet. We may give an idea of the way in which this proposition is established, as follows:-The area of a rectangle [RECTANGLE]-that is, the number of square feet it contains, is found by multiplying together the numbers of linear feet in the sides. Thus, if A B be 4 feet, and a c 5 feet, the number of square feet in the area is 4 x 5, or 20. Again, the number of feet described by a body moving with a uniform velocity, for a certain

number of seconds, is found by multiplying the number of seconds by the number of feet per second or the velocity. If, then, A B contain as many feet as there are seconds, and a C as many feet as the body moves through per second; so many feet as the body describes in its motion, so many square feet will there be in ABDC. That is, if we let A B represent the time of motion, and A c the velocity, the area A BDC will represent the length described in the time AB, with the velocity a C.

Not that ABDC is the length described, or AB the time of describing it; but AB contains a foot for every second of the time, and A B D C contains a square foot for every foot of length described. Similarly, if at the end of the time just considered, the body suddenly receive an accession of velocity D F, making its whole velocity BF per second; and if with this increased velocity it move for a time which contains as many seconds as B E contains feet, the length described in this second portion of time will contain as many feet as BEG F contains square feet; and the whole length described in both portions of time will be represented by the sum of the areas A B D C and BEGF. And similarly for another accession of velocity G I, and an additional time represented by EH. Now, let a body move for the time represented by A M; at the beginning of this time let it be at rest; and by the end let it have acquired the velocity MN: so that had it moved from the beginning with this velocity, it would have described the length represented by AMN P. Instead of supposing the velocity to be perpetually increasing, let us divide the time AM into a number of equal parts-say four, AB, BE, EH, H-and let one-fourth of the velocity be communicated at

the beginning of each of these times, so that the body sets off from A, with the velocity a c, which continues through the time represented by A B, and causes it to describe the length represented by A B DC. We know from geometry that B D, EG, and H K, are respectively one-fourth, one-half, and three-quarters of M N, which is also evident to the eye, and may be further proved by drawing the figure correctly, which we recommend to such of our readers as do not understand geometry. Hence, G E or BF is the velocity with which the body starts at the end of the time AB; EI at the end of A E; and HQ at the end of a H. Consequently, the whole length described is a foot for every square foot contained in A B DC, EBFG, EIKH, and HQN M, put together. But this is not a uniformly accelerated velocity, for the body first moves through the time A B, with the velocity Ac, and then suddenly receives the accession of velocity D F. But if, instead of dividing A M into four parts, we had divided it into four thousand parts, and supposed the body to receive one four-thousandth part of the velocity M N at the beginning of each of the parts of time, we should be so much nearer the idea of a uniformly accelerated velocity as this, that instead of moving through one-fourth of its time without acquiring more velocity, the body would only have moved one four-thousandth part of the time unaccelerated. And the figure is the same with the exception of there being more rectangles on A M, and of less width. Still nearer should we be to the idea of a perfectly uniform acceleration if we divided a M into four million of parts, and so on. Here we observe1, that the triangle A N M is the half of A P NM; 2, that the sum of the little rectangles ACDB, BFGE, &c., is always greater than the triangle ANM, by the sum of the little triangles A CD, DFG, &c.; 3, that the sum of the last-named little triangles is only the half of the last rectangle HQN M, as is evident from the inspection of the dotted part of the figure. But by dividing A M into a sufficient number of parts, we can make the last rectangle HQ N M as small as we please, consequently we can make the sum of the little triangles as small as we please; that is, we can make the sum of the rectangles A CD B, &c., as near as we please to the triangle A N M. But the more parts we divide A M into, the more nearly is the motion of the body uniformly accelerated; that is, the more nearly the motion is uniformly accelerated, the more nearly is ANM the representation of the space described. Hence we must infer (and there are in mathematics accurate methods of demonstrating it), that if the acceleration were really uniform, ANM would really have a square foot for every foot of length described by the body; that is,

since A N M is half of A PNM, and the latter contains a square foot for every foot of length which would have been described if M N had been the velocity from the beginning, we must infer that the length described by a uniformly accelerated motion from a state of rest, is half that which would have been described, if the body had had its last velocity from the beginning. If the body begin with some velocity, instead of being at rest, the space which it would have described from that velocity must be added to that which, by the last rule, it describes by the acceleration. Suppose that it sets out with a velocity of 10 feet per second, and moves for 3 seconds uniformly accelerated in such a manner as to gain 6 feet of velocity per second. Hence it will gain 18 feet of velocity, which, had it had at the beginning, would have moved it through 18 x 3 or 54 feet of length, and the half of this is 27 feet. This is what it would have described had it had no velocity at the beginning; but it has 10 feet of velocity per second, which, in 3 seconds, would move it through 30 feet. Hence 30 feet and 27 feet, or 57 feet, is the length really moved through in the 3 seconds.

Similarly we can calculate the effects of a uniform retardation of velocity. This we can imagine to take place in the following way. While the body moves uniformly from left to right of the paper, let the paper itself move with a uniformly accelerated velocity from right to left of the table. Let the body at the beginning of the motion be at the left edge of the paper, and let that edge of the paper be placed on the middle line of the table. Let the body begin to move on the

B

paper uniformly 10 inches per second, and let the paper, which at the beginning is at rest, be uniformly accelerated towards the left, so as to acquire 2 inches of velocity in every second. At the end of 3 seconds, the body will be at B, 30 inches from A, but the paper itself will then have acquired the velocity of 6 inches per second, and will have moved through the half of 18 inches or 9 inches; that is, a o will be 9 inches. Hence the distance of the body from the middle line will be c B, or 21 inches. Relatively to the paper, the velocity of the body is uniform, but relatively to the table, it has a uniformly retarded velocity. At the end of the fourth second, it will have advanced 40 inches on the paper, and the paper itself will have receded 16 inches, giving 24 inches for C B. At the end of the fifth second, A B will be 50 inches, a c 25 inches, and C B 25 inches. At the end of the sixth second, A B will be 60 inches, a c 36 inches, and B C 24 inches, so that the body, with respect to the table, stops in the sixth second, and then begins to move back again. We can easily find when this takes place, for, since the velocity on the paper is 10 inches per second, and that of the paper gains 2 inches in every second, at the end of the fifth second the body will cease to move forward on the table. At the end of 10 seconds it will have returned to the middle line again, and afterwards will begin to move away from the middle line towards the left. At the end of the twelfth second, it will have advanced 120 inches on the paper, and the paper will have receded 144 inches, so that the body will be 24 inches on the left of the middle line.

The general algebraical formulæ which represent these results are as follow. Let a be the velocity with which the body begins to move, the number of seconds elapsed from the beginning of the motion, g the velocity acquired or lost during each second. Then the space described in a uniformly accelerated motion from rest is gt; when the initial velocity is a, the space described in an accelerated motion is at + gt2, and in a retarded motion the body will have moved through at-g2 in the direction of its initial velocity if a t be greater than gt2, or will have come back and passed its first position on the other side by gt2-at, if at be less than gt2. In the last case it continues to move in the direction of its initial velocity for a seconds and proceeds in that direction through the space

For further explanation as to velocities which are accelerated or retarded, but not uniformly, see VELOCITY. ACCELERATION AND RETARDATION OF TIDES are certain deviations of the times of consecutive high-water at any place from those which would be observed if the tides occurred after the lapse of a mean interval. The interval between the culmination of the moon, or the occurrence of her principal phases, and the nearest time of highwater, is also called the retardation of the tide.

The tides are caused by the attractions exercised by both the sun and moon on the waters of the earth; but the effect produced by the moon exceeds that which is produced by the sun, and the difference is such, that the phenomena of the tides depend principally on the former. The mean interval between two consecutive returns of the moon, above and below the pole, to the meridian of any place, is 24h.

50m. 28-32s.; and since, neglecting all causes of irregularity, two lunar high-tides occur in that time, the mean interval between two consecutive lunar tides should be 12h. 25m. 14-16s.; while the mean interval between two consecutive solar tides should be 12h. Hence, if at the time of a conjunction or opposition of the sun and moon, the high tides which are produced by the actions of the luminaries separately were coincident, the next lunar tide would be retarded with respect to the next solar tide, by 25m. 14·16s., that is, by the excess of half a lunar day above half a solar day. These retardations continuing daily, the lunar high-water would coincide, at the time of quadrature, with the solar low-water, and thus produce the neap or diminished tides; after which, the like retardation continuing, the solar and lunar high-waters would again become coincident at the times of syzygy, and so on. The observed daily retardation of the lunar high-tides varies however according to the position of the moon with respect to the sun, to the moon's declination, and to the distance of that luminary from the earth. At Brest, when the sun and moon are in conjunction or in opposition, at the summer or winter solstice, the retardation is equal to 40m. 51.69s., and at the time of the equinoxes 37m. 38:15s. Again when the sun and moon are in quadrature at either solstice, the retardation is 1h. 7m. 27·498., and at the time of the equinoxes 1h. 23m. 16:34s.

If the earth were a solid of revolution, and were covered by the sea, the high tides produced by the sun and moon separately would, at any place, occur at the instants when those celestial bodies are on the meridian of the place; but such is not the fact in the actual condition of the earth; and local circumstances produce, at different ports, great differences in the intervals between the culmination of the sun or moon at the time of high-water, even on the days when the luminaries are in conjunction or opposition. The interval between the instant that the sun passes the meridian of a place and the occurrence of the solar hightide, is found to be greater than the interval between the transit of the moon and the occurrence of the lunar high-tide; and this acceleration, as it is called, of the lunar tide, is with much probability ascribed by Dr. Young to a difference in the resistances experienced by the waters on account of the different velocities which are communicated to them by the separate actions of the sun and moon.

It should be observed however that at Ipswich the time of highwater is nearly coincident with the time at which the moon passes the meridian of that port; and both at Glasgow and Greenock, the hightide generally precedes the transit (Mr. Mackie's Report,' at the seventh meeting of the British Association); but such phenomena are of rare occurrence, and at almost every place the high-tide occurs some time after the moon has culminated.

From a series of observations continued during sixteen years, at Brest, La Place, taking the excesses of the height of the evening tide above that of the morning for the day of syzygy, for the day preceding it, and for four days following it, has ascertained that at the syzygies which occur about the vernal and autumnal equinox the highest tides at that port take place 1-48013 days after the instant of the conjunction or opposition; and at the syzygies which occur about the summer and winter solstices they take place 1-54684 days after conjunction or opposition. Again, taking the excesses of the height of the morning tide above that of the evening for six days, as above, he ascertained that at the quadratures which occur about the equinoxes the highest tides take place 1.50964 days after the instant of quadrature, and at the solsticial quadratures 1.51269 days after such instant.

Mr. Airy (Tides and Waves,' Encycl. Metrop.) observes that these retardations cannot be accounted for by delays in the transmission of the tide-waves, since no cause for such delay can be imagined to exist in the Southern Ocean, where the waves are formed; and it is known that the time of high-water at Brest is only fifteen hours later than at the Cape of Good Hope: he conceives, therefore, that the retardation must be ascribed to friction. By taking the means of the daily retar dations of the morning and evening tides at Brest, La Place found that at the equinoctial syzygies such mean retardation was equal to 37m. 38s.; at the solsticial syzygies, 40m. 528; at the equinoctial quadratures, 83m. 16s.; and at the solsticial quadratures, 67m. 27s.

From a series of observed heights of the tides, Sir John Lubbock has determined that the highest tides occur at London 2013 days after the conjunction or opposition of the sun and moon; and at Liverpool, 1.68 days. ('Phil. Trans.' 1831, 1835.) Also, from the observed heights, Dr. Whewell has found that the highest tides occur at Bristol 1.667 days after the syzygies; and at Dundee 1639 days. (Phil. Trans.' 1838, 1839.) On the supposition that the mean retardation of the tide at London at the times of syzygy is 2:459 days, Mr. Airy has computed the moon's true hour-angle west of the meridian, at the time of high-water, for every half hour's difference in the time of her transit; and from the table it appears, that when the moon passes the meridian of London at noon (that is, at the time of conjunction), that angle, in time, is 1h. 57m. 17s.; when it passes at 3 P.M., the angle is 1h. 10m. 45s.; at 6 P.M., or at quadrature, Oh. 41m. 17s.; and at 9 P.M., 1h. 55m. 29s. The hour angle is the greatest at 104 P.M., when it is equal to 2h. 9m. 55s.; and at 114 P.M., or nearly at the time of opposition, it is 2h. 3m. 9s. : all these times are found to agree very nearly with the results of observation. From such results it is ascertained that, on the days following the times of syzygy and quadrature, the intervals between the time of the moon's

transit and the instant of high-water are nearly equal; but from conjunction to the first quarter, and from opposition to the third quarter, the intervals are less than on the days of syzygy and quadrature, or the time of high-water is accelerated; while from the time of the first quarter to that of full moon, and from the third quarter to the new moon, the interval is greater, or the time of high-water is retarded. The time first mentioned (1h. 57m. 17s.) is that which is called the Establishment, at London; but Dr. Whewell recommends that the mean of the times (1h. 25m. 35s.),which he calls the mean, or correct, establishment, should be used in preference, because it differs less, on any day, from the vulgar establishment.

From Dr. Whewell's paper in the Philosophical Transactions' for 1836, we find that at Liverpool, when the moon passes the meridian at 30m. P.M., her hour-angle at the time of high-water is 11h. 18m. 16s.; when the hour of transit is 6 P.M., the hour-angle is 10h. 40m. 52s.; and when it is 114 P.M., the angle is 11h. 33m. 36s. The mean, or correct establishment, at that port, is 11h. 6m.

The acceleration and retardation of the times of high-water must evidently depend on the distance of the moon from the earth, and they are presumed to be proportional to the difference between the actual and the mean horizontal parallax of the luminary: this is called the parallax inequality of the tides; and La Place has determined, for the lunar tides, that the ratio of the daily variations, when the moon is in apogee and in perigee, is nearly as 2227 to 2899. He estimates the variation at 9m. 26 4s. for a change equal to one minute in the moon's apparent semidiameter at the times of conjunction and opposition, and at one-third of that quantity at the times of quadrature. Corresponding variations, but less in amount, take place with respect to the solar tides. ACCENT (in Mathematics). To avoid the confusion arising from the use of many letters in an algebraical problem, and on other accounts, it is customary to signify different magnitudes of the same kind, or magnitudes similarly connected with the question, by the same letter, distinguishing these magnitudes from one another by accents. It is, therefore, to be understood that the same letter with two different accents may stand for magnitudes as different in value as those represented by different letters. The convenience of the accent may be illustrated as follows:-If a men can do b things in c days, and e men can do ƒ things in g days, we have the following equation:

afc=ebg.

Now, instead of using e, f, and g, in the second part of the question, let us use the letters which stood for the corresponding quantities in the first part, with accents; that is, let a' men do b' things in c' days. The equation then becomes

a b c = a' b c'.

In this new form of the equation some things are evident to the eye, to ascertain which, had the first equation been used, we must have had recourse to the question itself. For instance, that if a", b", c" express men, things, and days, as above, ab" ca" b c", only placing two accents now where there was one before. In many investigations, the judicious use of accents gives a symmetry to the processes and expressions which could scarcely be otherwise obtained.

For the unmathematical reader, we may illustrate the use of accents in the following way :-Let us suppose a bookcase to consist of four rows of shelves, each divided into six compartments. If we call the six compartments in the lowest range A, B, C, D, E, and F, respectively, we might let the compartment directly over A be called a, and so on; but it would be much simpler and more easy of recollection to call this compartment a', the one over it in the third row A", and so on. Thus each letter would indicate a certain vertical line of compartments, while the accent would point out in which horizontal line the one designated is to be found. This is precisely the mathematical use of the accent. All quantities of the same kind, or which the problem places in similar positions, are designated, with regard to this question, by the same letter. The accented letter a' s read a accented, or a dashed; a" is read a twice accented, or a twice dashed, or, more conveniently, though without much attention to idiom, a two dash, &c. When accents become too many to be used with convenience, the Roman figures are substituted for them. Thus air would be used for a""" at Cambridge, of late years, the i and v are an accent, and two accents joined at the base, which is very expressive. The Roman figures prevent air from being taken for a', or a multiplied three times by itself. The young algebraist should be cautious in his use of accents, until experience has taught him to do so with propriety.

ACCENT (in Music), signifies, in a general sense, emphasis, and is either grammatical or oratorical.

Grammatical accent is the emphasis, always slight, given to notes which are in the accented parts of a bar. If the first, fifth, and ninth notes of the following series are accented, the whole will be divided into bars of common or equal time:

If an emphasis be given to the first, fourth, and seventh notes, the series will divide into bars of triple time-thus:

Again, an entirely different effect will be produced by throwing the accent on the second, sixth, and tenth notes of the same series:

е

So important is this accentuation, that the above examples give really different tunes, although the notes are the same. Oratorical accent is expression-is the accent dictated by feeling— and not confined to any particular part of the bar. It is often required, though the composer may not have marked it by any sign, but left it to the knowledge and taste of the performer to discover and enforce. Commonly, however, the terms rinforzato (strengthened), and sforzato (violently forced), are used for the purpose, though these participles are too often thought synonymous. An acute angle (→) is also employed to indicate such emphasis.

The accented parts of a bar are such as naturally require some emphasis. In common time, the bar of which is divided into four parts, the first and third are accented, the second and fourth unaccented. In triple time of three crotchets, the accent is on the first; the second and third are usually unaccented; but a slight accent is sometimes given to the third or last note. In three-quaver time the accent is on the first quaver only. In six-quaver time, it is on the first and fourth quavers. Nine-quaver and twelve-quaver times, which are only multiples of the two former, and are seldom used, follow the same rule as those. The extremes, however, of slowness and quickness in times, though not altering their names, change the number of accented parts. [CLEF; TIME.]

ACCENT. When a child begins to read, he is apt to pronounce all the syllables of a word in the same key, with the same loudness and clearness, dwelling the same time upon each, and pausing the same time between each pair. He soon, however, learns that, in nearly every word there is one syllable at least which must be distinguished from the rest by a more impressive utterance, as in the examples respect, respectful, respectable. If the word is a long one, it requires a second accent, as respectability, mánufactory, immortalise. On the other hand, when short words come together, one or two are often devoid of accent, as in the phrase on the top of a hill. When it is stated that the accented syllable is pronounced more impressively than the rest, it is not meant that all accented syllables are to be equally impressive. In the examples given above, the first accent in manufactory seems to be weaker than that on the third syllable; so the last accent in immortalise, and that attached to the prepositon on, among the six monosyllables, on the top of a hill, are comparatively very faint. The consideration of accent often determines whether or not we pronounce the initial [See A or AN]; and, consequently, whether the article an or a is to be used before such a word. Upon accent depends the melody of verse, at least in modern languages. Of the ancient, particularly the Greek accent, it is better to abstain from speaking, because the opinions of people on the subject of Greek accent are both unsettled and contradictory. We may remark, however, that it is the practice of the modern Greeks, in a very great number of instances, to put the chief stress on that syllable which, in our printed Greek books, has the accentual mark (') on it; but, in doing this, they frequently and unavoidably neglect the stress on those syllables which we are accustomed to pronounce most emphatically. It is said that the principle of Greek versification is quantity, or, as it is defined, the mere duration of a sound. Possibly, on a closer examination of the question, it would be found, that what the ancients meant by quantity, was not very different from what we mean by accent. A writer in the Transactions of the Philological Society for 1855' (pp. 119-145), has put forward arguments to show, that to accentuate the writings of Homer, Aschylus, Thucydides, as is the present practice, is simply an anachronism, inasmuch as the accentual marks were introduced at a much later period for the very purpose of denoting the changes of pronunciation, when the distinctive vowels w and y were no longer trustworthy guides. It does not accord with the nature of the present work to enter into details; but we may be permitted to say, that the challenge to scholars contained in the paper has not yet been accepted. To return to the safer ground of our own language, the reader of our older writers, Shakspere and Milton, for instance, should know that the accents of words from time to time are changed, and even variable at the same time. Thus, the verb which we call triumph, was with Milton generally triumph; the noun and the verb being commonly distinguished by him in the same way as produce the noun and produce the verb are at the present day. What we call spirit, was with him more commonly spirite, or almost sprite; and aspect, process, were aspect, procéss. Even in our time, advertisement has become advertisement. In these changes, the usual tendency in our language is, and has been, to throw the accent farther back from the end of the word. Such a tendency is, perhaps, inherent in all languages, and seems to arise solely from an endeavour to save labour by rapidity of utterance,

The symbols employed to denote accents are three, the acute ('), the grave ('), and the circumflex (). We have hitherto spoken only of the first. The second in the ancient languages is said to denote the opposite to the acute, or, perhaps, the absence of it; while the circumflex, we are told, marks a compound of the two, first a rising and then a falling of the voice in the articulation of the same syllable.

These three little marks, as employed the orthography of the French language, have a signification altogether different. As the French, like all other languages, is deficient in the number of characters used to mark the vowel sounds, it has been found convenient to employ the three symbols given above. Thus, the sounds of e, é, è, e, in the mouth of a Frenchman, differ not so much in point of accent as in the real articulation. Emphasis differs from accent, and is properly used with reference to rome one word, or part of a sentence, to which a speaker wishes to draw attention by giving it a more marked pronunciation. [EMPHASIS.] ACCEPTANCE. [BILL OF EXCHANGE.]

ACCESSARY (from the low Latin accessorius or accessorium), is, in law, one who is guilty of an offence which is a felony, not as chief actor, but as a participator without being present at the time of the actual committing of the offence, as by command, advice, instigation, procurement, or concealment, &c.

A man may be accessary either before the fact, or after it.

An Accessary before the Fact is defined by Lord Hale to be one who, "being absent at the time of the crime committed, doth yet procure, counsel, or command another to commit a crime." The offender's absence is necessary to constitute him an accessary, as otherwise he would be a principal; and he must have procured the commission of the crime, either by direct communication with the actual perpetrator, or by conveying his advice or command through some indirect channel. But the mere concealment of a felony intended to be committed, without actual instigation, will not make a man an accessary; as that is only a misprision of felony. It is an established rule, that where a man commands another to commit an unlawful act, he is accessary not merely to the act commanded, but to all the consequences that may ensue upon it, except such as could not in any reasonable probability be anticipated or feared: as, for instance, if he commands another violently to beat a third person and he beats him so that he dies, the person giving the command is guilty as accessary to the murder consequent upon the act, notwithstanding that it may never have been his intention that a crime of so deep a dye should be committed. a man will not be guilty as accessary before the fact if he command another to kill A, and he kills B, because the particular crime he contemplated has never been completed. It is otherwise where the directions have been substantially pursued, although the crime may not have been committed precisely in the manner in which it was commanded to be done, as where a murder is effected by means of stabbing instead of poisoning.

But

An Accessary after the Fact is one who, knowing a man to have committed a felony, receives, harbours, or assists him. In general, any assistance given to a felon to hinder his being apprehended, tried, or suffering punishment, as by affording him the means to escape the pursuit of justice, will constitute the assister an accessary after the fact; but it is not so if the assistance given have no such tendency, as when clothes or necessaries are supplied to a felon in gaol. Although any act done to enable the criminal to escape the vengeance of the law will make a man guilty as accessary after the fact, a mere omission to apprehend him, without giving positive assistance, will not have that effect. Also, if the crime be not completed, at the time of the relief or assistance afforded, the reliever or assister is not judged an accessary to it; as where a mortal wound has been given, but the murder is not then consummated by the death of the party yet, the crime once complete, not even the nearest ties of blood can be pleaded in 'justification of concealment or relief, except alone in the case of a wife, whom the law supposes to be so much under the coercion of her husband, that she ought not to be considered as accessary to his crime by receiving him after it has been committed.

By 7 Geo. IV. c. 64, and 11 & 12 Vict. c. 46, the trial and punishment of accessaries before the fact is assimilated to that of the principal felon. Accessaries after the fact are, by the latter statute, made punishable as for a substantive felony, with imprisonment proportioned to the heinousness of the original crime, but the imprisonment is not to exceed two years. The receiver of stolen goods, whose offence is of the nature of that committed by an accessary after the fact, is, by 7 & 8 Geo. IV. c. 29, made liable to fourteen years' transportation: or now to a similar period of penal servitude; 16 & 17 Vict. c. 99; 20 & 21 Vict. c. 3. Formerly no accessary could be tried until after the conviction of the principal, the crime of the former being regarded as, in a manner, dependant on that of the latter; but the law is now altered in this respect, by 11 & 12 Vict. c. 46; and 14 & 15 Vict. c. 100. It is now competent to try and convict him without waiting for the conviction of the principal.

The distinction between principals and accessaries holds only in cases of felony.

ACCIDENT. [PREDICABLES.]

ACCIDENTAL COLOURS. A term applied to the ocular spectrum which is usually seen when the eye has been steadily fixed for some time upon a coloured object. Thus, if we look at a red wafer upon a

sheet of white paper for about half a minute, and then turn the eye from the wafer to the white paper, we see an image, or spectrum, of the wafer of a bluish green colour; this is the accidental colour of the red, and if we repeat the experiment with other colours, they will in like manner furnish ocular spectra: thus an orange colour will furnish a blue spectrum, yellow will give indigo, and so on, and it will be found in each case, that the colour of the object, added to that of the spectrum, will make up all the colours of white light; hence accidental colours are also called complementary colours. [LIGHT.]

ACCLIMATION is a term applied to that change in the human system produced by residence in a place whose climate is different from that to which it has been accustomed, and which enables it to resist those causes of disease which readily act upon it before such change has taken place. A person is thus rendered similar in constitution to the natives of the country which he has adopted. This subject is one of great importance, and has not yet received the attention it demands. As far as present evidence goes, it appears that the white races attain their highest physical and intellectual development, the greatest amount of health, and reach the greatest age, above 40° in the western and 45° in the eastern hemispheres. Whenever they pass below these latitudes they begin to deteriorate and exhibit unmistakeable symptoms of decadence in both health and strength. The same law holds good with the dark races of the tropical parts of the earth. The negro who lives in the interior of Africa is killed by cold. The limits of his health and strength are found at 40° north or south. If he proceeds to higher latitudes, he deteriorates and becomes exterminated. In the northern states of America the mortality of the black population is double that of the white.

"The laws of climate show that each race of mankind has its prescribed salubrious limits. All of them seem to possess a certain degree of constitutional pliability by which they are able to bear, to a certain extent, great changes of temperature and latitude; and those races that are indigenous to temperate climates support best the extremes of other latitudes. The inhabitants of the arctic regions, as also of the tropics, have a certain pliancy of constitution; and while the inhabitants of the middle latitudes may emigrate 30° south or 30° north with comparative impunity, the Esquimaux in the one extreme, or the Negro, Hindoo, or Malay, in the other, have no power to withstand the vicissitudes of climate encountered in traversing the 70° of latitude between Greenland and the equator. The fair races of northern Europe below the arctic zone find Jamaica, Louisiana, and India, to be extreme climates; and they and their descendants are no longer to be recognised after a prolonged residence there. When an Englishman is placed in the most beautiful part of Bengal or Jamaica, where malaria does not exist, and although he may be subjected to no attack of acute diseases, but may live with a tolerable degree of health his threescore years and ten, he nevertheless ceases to be the same healthy individual he once was; and, moreover, his descendants degenerate. He complains bitterly of the heat, and becomes tanned; his plump plethoric frame becomes attenuated; his blood loses fibrine and red globules; both mind and body become sluggish; gray hairs and other marks show that age has come on prematurely-the man of forty looks fifty years old; the average duration of life is shortened (as shown in life insurance tables); and the race in time would be exterminated if cut off from fresh supplies of emigrants from the home country. Our army medical historians tell us that our troops do not become acclimatised in India. Length of residence in a distant land affords no immunity from the diseases of its climate, which act with redoubled energy on the stranger from the temperate zones. On the contrary, the mortality among officers and troops is greatest among those who remain longest in those climates." (Johnson, Martin, Tulloch, Macpherson, Boudin.) Dr. Macpherson also makes the significant remark, that the small mortality among officers compared with soldiers, in India, is due to the greater facilities they enjoy of obtaining change of climate when they fall sick. Although the constitution of the man may be so modified that comparative health may be retained, yet there is a morbid degradation of the physical and intellectual constitution. If, however, he or his descendants are taken back to their native climate, they may yet revert to the healthful standard of their original types. The good effects of limiting the period of service of our troops abroad to three years, has shown this in sustaining for a greater period the strength of the regiments; a protracted residence of the European regiments in India having been followed by the most disastrous results. European regiments in India have melted away like the spectres of a dream. A thousand strong men form this year a regiment: a year passes, and one hundred and twenty-five new recruits are required to fill up the broken column; and eight years having come and gone, not a man of the original thousand remains in the dissolving corps."

"With regard to the Bombay Fusilier European regiment, for instance, Dr. Arnot has shown that its losses average 104 per 1000 per annum; a loss equivalent to the entire absorption of the regiment in nine years and seven months. In Bengal also it is an ascertained fact, that a British regiment of 1000 men dissolves entirely away in 11 years, even in favourable times, and with all the improved conditions of the service. Dr. Arnot's statistics show that the Bengal army loses annually 9 per cent. of its numbers, giving a total loss in eight years of upwards of 14,005 men out of an army of 156,130 men.' (Aitken's Handbook of Medicine.')

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