the unpleasant smell of sulphur belonging to it; to remedy this, one of the gas companies at Liverpool is in the habit of using salt, in the ratio of 14 lbs. to every charge of coal; this is said to lessen considerably the sulphureous exhalation from the coke. From various and somewhat conflicting reports of experiments made, it would appear that the relative profitableness of coke and coal as fuel depends greatly on locality; the ratio between the prices of the two being by no means uniform. If, on the one hand, manufacturers are trying to substitute coke for coal in many fixed furnaces, railway companies, on the other, are seeking to substitute coal for coke in locomotives. The experiments require to be carried to a much greater extent, before these problems can be effectually solved. Many patents have been obtained for peculiar methods of preparing coke; but they do not require any lengthened notice. One is for a mode of applying muriatic acid to small coal, to dissolve the carbonates of lime and magnesia, and other impurities, after which the roasting is effected. Muriatic acid being rather a costly liquid when thus employed, it is suggested to employ the refuse acid from alkali works. Another is for a mode of obtaining ammoniacal salts. The products of combustion are to be drawn off by a blower into a flue, in which is placed a refrigerator; they then pass into a condensing chamber, where they come in contact with surfaces over which a stream of dilute sulphuric acid is trickling; the ammonia is taken up, and the noncondensible gases allowed to pass off.

COLCHICINE, the active principle of the meadow saffron (Colchicum autumnale). It was at one time regarded as identical with veratrine. It is soluble in water, alcohol, and ether. It forms salts with the acids, which are bitter, acrid, and poisonous. In small doses it causes purging. COLCHICUM, Medical uses of. In a small dose, colchicum causes an increased flow of urine, and more frequent evacuations from the intestinal canal, and occasionally augmented secretion from the skin; in larger doses, frequent evacuations from the intestines, accompanied with pain and tenesmus, and desire repeatedly to empty the bladder. Still larger doses cause increase of all these actions, with vomiting and sense of burning in the throat, insensibility and stiffness of the tongue, escape of blood into the intestinal canal, vomiting of blood, and a flow of bloody urine. Great disturbance of the nervous system is likewise observed, as in other cases of poisoning with acrid substances. The same appearances are found in the intestinal canal, if the poison be injected into the veins. Even the milk of cattle which have eaten the meadow-saffron becomes capable of causing death. (Vogt.)

In a moderate dose, colchicum seems to increase the quantity and improve the quality of all the secretions of the intestinal canal and the collatitious viscera, especially the liver; but it likewise exerts a sedative action on the heart. Chelius says that in twelve days it doubles the quantity of uric acid found in the urine, a circumstance which explains its utility in gout and rheumatism. The diseases in which colchicum is most useful are, dropsy, when a small dose is prescribed; gout, in which larger are used; and rheumatism, in which its beneficial influence is first felt on the liver (which is almost always disordered in these diseases), and afterwards on the kidneys, from which a larger portion of uric acid is excreted, and the formation of gout-stones (urate of soda) in some degree prevented. As acid in the stomach renders the action of colchicum more violent, magnesia is usually given along with it. The acetate and acetous extract are the best forms of administration.

COLCOTHAR. [IRON, Sesquioxide of.]
COLD. [CATARRH; HEAT.]

COLE, COLZA, a cultivated state of the Brassica napus, which does not form a close head, like cabbage, but has sessile heart-shaped leaves. It is cultivated for its seeds, from which an oil is expressed, which is much used for burning in lamps, and in the manufacture of leather and soap.

There are two varieties of cole, one with white flowers and another with yellow; the latter is the hardiest, and consequently most generally cultivated.

It requires a good loamy soil, well manured, to produce a good crop of cole seed. In rich land lately broken up from pasture, or fenny land newly drained, it grows luxuriantly and gives a great return. It is thought to be a great exhauster of the soil. Half a gallon of seed is drilled in rows 14 or 16 inches apart about the end of July, and left thinned out until the following year, when it is cut in June and July, yielding 20 to 30 bushels of seed, which is sold at from 88. to 108. a bushel. An oil is expressed from it, and the refuse, a rape cake, is made as food for sheep or cattle; being worth for that purpose more than its comparatively low price, 61. per ton, when oil cake is 10l. to 12. a ton, would indicate. In a rotation, cole is considered as a good crop to precede wheat. Like rape, which is another variety, it is sometimes sown to be fed off by cattle and sheep on land which is not so well adapted to the growth of turnips. [RAPE.]

COLIC (from @λov, colon), dolor colicus, called by Sydenham and the old English writers the dry belly-ache; a disease attended with severe pain of the bowels, remitting and recurring at intervals, with constipation, and without fever. The seat of this malady is conceived to be chiefly, if not entirely, in that portion of the large intestines called the colou, and hence its name. It arises from a great variety of causes,

and assumes a corresponding variety of forms, many of which have received distinct names; but pain and constipation of the bowels, with the absence of fever, are common to them all; and this concurrence of symptoms is essential to the medical notion of colic. The pain in colic often most distinctly follows the course of the colon, while the morbid distension and contraction of the bowel (for these two morbid states alternate with each other, and attack successively different portions of the intestines) often become visible to the eye. The colon receives all that portion of the food which is not converted into chyle, together with all those portions of the pancreatic, biliary, and intestinal secretions, which do not form component parts of the chyle. Consequently it has a considerable mass of matter to carry downwards and convey out of the system. It is provided with muscular fibres, very much larger than those which belong to the small intestines. These fibres form three large bands, which are placed in a longitudinal direction along the intestine, and which produce the effect of dividing the inner surface of the colon into folds, so disposed as to form little distinct apartments called cells. In these cells the feculent matter, which should be slowly but progressively carried downwards, is sometimes collected and closely impacted, so that when at length rejected it has the form of those cells constituting hard rounded balls, termed scybala. The natural stimulus to the muscular fibres of the colon is the resinous portion of the bile [BILE, NAT. HIST. Div.], together with the non-nutrient portion of the aliment. It is easy then to conceive how a loss or diminution of the contractile power of these fibres may occasion the constipation incident to colic, attended with the retention of the feculent matter in the cells of the colon; how a suppression or an altered condition of the bile may contribute to the same effect; and how an acrid quality of the bile and of the non-nutrient portion of the aliment may produce the irritation and pain incident to colic. The colon then, both from its structure and function, it is obvious must be peculiarly predisposed to such an affection as that to which, from the frequency with which it is the subject of the malady, it has given a name. It is perhaps desirable that the term colic should be restricted to the designation of a disease of a definite character, seated in the colon; and some medical writers do so limit the use of the term, though others give it a more extended signification, and with less propriety include under it diseases which do not arise primarily in the colon, but in some neighbouring organ, the colon being only secondarily and sympathetically affected.

Colic, properly so called, is attended with severe griping pains in the bowels, which often follow very accurately the course of the colon; sometimes having their seat in one portion of it and sometimes in another. These pains remit for a time, affording intervals of ease; but they soon return with increased violence. They are often relieved by pressure, a character by which they are distinguished from pain occasioned by inflammation, the latter being always increased by pressure. The pain is usually attended with a greater or less degree of flatulence. The flatus sometimes collects to such an extent as to occasion a prodigious dilation of the bowels, greatly increasing the pain. When the digestive process is perfectly natural, it is always attended with the evolution of some portion of gas; in disordered states of digestion, the quantity of gas is often very much increased. While one portion of the intestine is thus preternaturally distended, another portion is in a state of preternatural contraction, from the irregular spasmodic action of the muscular fibres of the colon, excited by the irritating cause-whatever it may be-which produces the disease. These irregular spasmodic contractions of the colon are always present when this disease is severe, and are intensely painful. The constipation, which is so constant as to be a diagnostic character of the malady, is often long continued and obstinate, and the consequent accumulation of feculent matter is very great. To the preceding train of symptoms is very frequently superadded vomiting, which is often urgent and most distressing; and in cases of the greatest severity, the action of the whole intestinal tube above the seat of the disease is inverted, and the fæces are mixed with the matter vomited. Occasionally there is hiccough, and very often the griping pains are attended with loud rumbling noises in the interior of the intestines.

It is unnecessary in this place to enter into the details of the varieties of this malady to which physicians have assigned distinct names, since these varieties are merely modifications of the same disease produced by different causes. The preceding account will be sufficient to give to the general reader a distinct conception of the nature of the malady, and of the causes which produce it; and it is only necessary to observe respecting the treatment, that the two great principles on which the cure depends are the complete evacuation of the intestines, and the strict regulation of the diet. It is indispensable that the evacuation of the intestine of its accumulated and irritating contents should be complete, and this is best effected by an alternation of mild and unirritating aperients, with opiates. After the intestine has been fully relieved of its load, it is necessary to persist in a course of mild aperients for a considerable time; because the bowel long remains in an irritable state, and very slight causes are apt to occasion a relapse. For the same reason only the most bland and unirritating substances should be taken as food; all acid and acrid matters in the solid and all stimulating matters in the fluid aliment should be most carefully avoided.

The accidental introduction of lead into the system often produces symptoms resembling those of ordinary colic. [PAINTER'S COLIC.] COLISEUM, OR COLOSSEUM. [AMPHITHEATRE.] COLLATERALS. [CONSANGUINITY.] COLLATIO, or MOSAICARUM ET ROMANARUM LEGUM COLLATIO, or LEX DEI, is a compilation, probably made in the 6th century of our era. It consists of a comparison between the Law of Moses and the Roman Law, in sixteen titles. Each title has certain legal rules at the head from the Law of Moses, headed thus," Moses dicit;" to which are subjoined, by way of comparison, rules of Roman law taken from the five Roman jurists-Papinian, Paulus, Gaius, Ulpian, and Modestinus-and from the three compilations which preceded that of Justinian-the Gregorianus Codex, Hermogenianus Codex, and Theodosianus Codex. The value of the Collatio consists solely in the extracts which it contains from the source above mentioned. The last and best edition of the Collatio is by Blume, in the Bonn edition of the Corpus Juris Ante-Justinianei,' and in the separate edition of 1833, 8vo. The first edition is by P. Pithou, Paris, 1573, 4to. It is also printed in Schulting's 'Jurisprudentia Vetus ante-Justinianea,' Leyden, 1717.

COLLATION. [BENEFICE.]

COLLEGIUM, or CONLEGIUM, from the word colligo, "to collect or bring together," literally signifies any association or body of men ; but a technical meaning was attached to it, namely, that of a number of persons joined in some office or employment, or living by common rules. The word Corpus was also used in the same sense (D. 50, 6, 5), and those who were members of a collegium or corpus were hence called corporati. The word Universitas was sometimes used as equivalent to Collegium or Corpus, but it had also the more general signification of "community," or " collective body of citizens." In the Roman polity collegium signified any association of persons such as the law allowed, requiring confirmation by special enactment or by a senatus consultum, or an imperial constitution, in which case it was called Collegium Legitimum. A collegium necessarily consisted of three persons at least. (Dig. 50, tit. 16, 1. 85.)

In general, any association or collegium, unless it had the sanction of a senatus consultum, or of the emperor, or were established by a lex, was illegal (illicitum); and on proof of such illegality, might be dissolved by imperial letters (mandatis), constitutions, and senatus consulta; and when dissolved, the members were allowed to divide the property of the association according to their respective shares. (D. 47, 22, 3 pr.) The members of a collegium were called sodales; the terms and object of their union or association might be any that were not illegal.

A great variety of collegia (many of them like our companies) existed at Rome and in the empire, as we see by ancient writings and inscriptions, such as the Collegia Fabrorum, Pistorum, Pontificum, Fratrum Arvalium, Virorum Epulonum, Augurum, &c. Some of these, such as the colleges of Pontifices and Augurs, were of a religious character. These collegia possessed property as a corporate body; and in the time of the Emperor Hadrian, if they were collegia legitima, they could take a legacy or bequest (C. 6, 24, 8) in their corporate capacity. Collegia were allowed, as a matter of course, to have a common chest, and an actor, syndicus or attorney, to look after their rights and interests, and appear on their behalf. Plutarch ascribes the origin of colleges, as a political institution, to Numa Pompilius; and Dionysius mentions an ancient law, passed by Tarquin the Proud, for the purpose of putting down the societies and colleges which were then in existence at Rome. That the institution was often perverted to improper ends, we have proof not only in the writings of the Roman authors (see, among others, Cicero, Pro Sextio,' c. 15), but in the repeated enactments that were aimed at the colleges from time to time. (See Suetonius, Julius Cæs., c. 42; and Augustus,' c. 32.) (D. 3, 4, 1, 1.) The maxims-that what was due to a university was not due to the individual members; and that the debts of universities were not the debts of the individual members; and that even though all the members were changed, the university still existed-comprehend the essential notion of a corporation as understood by the law of England.

In England, a COLLEGE is an eleemosynary lay corporation, of the same kind as an hospital, existing as a corporate body either by prescription or by the grant of the king. But as regards Christ's Church, Oxford, that has been held to be a spiritual body, as being, not a college, but a dean and chapter. (Fisher's case, Bunbury, 209; and in Pitt v. James, Hobart, 122.) Trinity College, Cambridge, was expressly held to be a spiritual corporation, under the Stat. 1 & 2 Phil. & Mary. A college is not necessarily a place of learning. An hospital, also, is not necessarily a mere charitable endowment, but is sometimes a place of learning, as Christ's Hospital, London. Its particular form and constitution depend on the terms of the foundation. (Phillips v. Bury, 1 Lord Raymond 5; and Skinner, 447.) A college consists of a head, called by the various names of provost (præpositus), master, rector, principal or warden, and a body of fellows (socii), and of scholars also, besides various officers or servants, according to the peculiar nature of the foundation. A college is wholly subject to the laws, statutes, and ordinances which the founder makes, and to the visitor whom he appoints, and to no others. All elections, and the general management of a college, must be in conformity with such statutes or rules. If a

college does not exceed its jurisdiction, the king's courts have no cognisance, and expulsion of a member is entirely within its jurisdiction, and therefore, in general, a mandamus cannot be had to restore a fellow to his fellowship (Comyn's Digest, Visitor,' s. 15); nay, more, where a college, as visitor, had removed an individual from a mastership in a school, not only has a mandamus been refused (Craford's case, Styles, 457), but the Court of Chancery refused to interfere by injunc tion (Whiston v. Dean and Chapter of Rochester, 18 Law Journal, Chancery, 478). If there is no special visitor appointed by the founder, the right of visitation, in default of the heirs of the founder, devolves upon the king, who exercises it by the great seal; and in such case it is to be exercised by the crown cyprés (or as near as possible) to the manner in which it was exercised by the founder and his heirs. (R. v. St. Catherine Coll., 4 Term Rep. 243.) When the king is founder, his successors are the visitors.

The general power of a visitor is to judge according to the statutes of a college, to expel and deprive for just reason, and to hear appeals. His precise powers are determined by the founder's statutes, and if there are any exceptions to his power, the jurisdiction in such excepted cases devolves on the king. Certain times are generally named in the statutes for visitation, but the visitor may visit whenever he is called in, it being incident to his office to hear complaints. So long as a visitor keeps within his jurisdiction his acts cannot be controlled, and there is no appeal from him, as was decided in the above-mentioned case of Phillips v. Bury. The visitors are not bound to any particular forms of proceeding, and, in general, want of jurisdiction is the only ground on which they are liable to prohibition. If a visitor's power is not limited or defined, he must use his best discretion. If a power to interpret the statutes is given to any person, as to the bishop of the diocese, this will constitute him and his successors visitors. The heirs of a founder cannot alter the statutes, unless such a power is expressly reserved; and it appears, that where the king is founder, his successors cannot alter statutes without the consent of the college, unless such a power is reserved. But as to the power to alter statutes, it must be observed, that in the case of the crown at least, it has not unfrequently been done, though such a power might now possibly be disputed, unless expressly reserved to the founder and his heirs by his original statutes. In Attorney-General v. Archbp. of York (2 Russell & Mylne, 468), Lord Brougham said, "No man can doubt what the powers of a visitor are. In practice they are perfectly uncontrolled, of removal, new appointment, variation, and alteration. They are, in truth, of a most extensive and arbitrary nature." But Lord Mansfield has expressed strong doubts whether a visitor can repeal or alter statutes without an express power given by the founder. (1 Burrows, 201.) Whenever a visitor is appointed, the Court of Chancery never interferes with the internal management of a college; how far it exercises jurisdiction in matters pertaining to the management of the funds, on the ground that as to the funds of a college, those who possess the legal estate are in the situation of trustees, is a doubtful point. Certainly, in the case of charitable foundations, where the governors or visitors are trustees for the charity, and are found to be making a fraudulent use of their powers, the Court of Chancery can and will interfere on information (see 15 Ves. 314); and even where the founder has left directions in his will vesting the sole government and management of the charity in the visitors, the Court of Chancery will exercise control, where such visitors are also trustees of the charity estates. It is said, however, that such interference of Chancery with visitors, is only where both the legal estate and the receipt of the rents are vested in the visitors. (Att.-Gen. v. Middleton, 2 Ves. sen. 328; see Green v. Rutherforth, 1 Ves. sen., 473 & 475.) In colleges, when a new foundation is engrafted on an old one, it becomes part of the old one, and subject to the same visitorial authority, unless in the indenture of annexation by which the college takes the additional foundation a difference in the matter of visitation is expressly declared (R. v. Bishop of Ely, 1 W. Blackstone, 70); unless new statutes are given with the new foundation, in which case the college accepting the foundation will be bound in all respects by the new statutes, for they take the benefit cum onere. (See the cases collected in Grant on Corporations, 542, u.)

The validity of all elections in colleges must be determined by the words of the founder's statutes or rules. In the disputes that have arisen on elections, the point has generally been, whether the master's concurrence is necessary, or whether a bare majority of the electors, of which electors the master is one, is sufficient. (See, as to this, Grant on Corporations, 532, 538, 539.) In Catharine Hall, Cambridge, fellows must be elected "communi omnium consensu aut saltem ex consensu magistri et majoris partis communitatis;" and it was held by Lord Eldon, upon these words and another clause which follows, that no election was valid in which the master did not concur.

The statutes of Clare Hall, Cambridge, require "that the election of a fellow shall be by the master and the major part of the fellows present;" and here it was held, on reference to the chancellor, the Duke of Grafton (A.D. 1788), that a valid election might be made without the concurrence of the master. But this interpretation is obviously wrong, and is referred to with disapprobation in the case of Queen's College, Cambridge (5 Russell, 97), in which case the lordchancellor, Lord Lyndhurst, in declaring his opinion with reference to

the college then before him to be that the concurrent voice of the president was necessary in all elections of its fellowships, expressly rested his decision on the judgment of Lora Eldon in R. v. Catharine Hall, 4 T. R. With reference to the subject of election to and tenure of fellowships, two modern cases are deserving of notice as bearing upon the construction which the Court of Chancery puts upon college statutes: these are In re St. Catharine's Hall (1 McNaght. & Gord. 467), and exparte Edleston (1 De Gex, McN. & Gord. 742). The latter case is important as maintaining the principle that new statutes embodying old ones do, in the absence of any express intention to the contrary, get rid of dispensing (or remedial) statutes. Before dismissing this topic, it should be noticed, that the whole matter is now (1859) in a transition state, the statutes of the different colleges being under the revision of a committee appointed by the government for that (among other) purposes. Colleges (13 Eliz. c. 10) could not grant leases of their land beyond twenty-one years, or three lives; and in such leases the accustomed yearly rent, or more, must be reserved, payable yearly during the term. By 18 Eliz. c. 6, in all leases made by colleges in the universities, and by the colleges of Winchester and Eton, one-third of the whole rent must be reserved in corn. By a very recent statute (21 & 22 Vict. c. 44), the subject of college leases and powers to sell and exchange has been materially affected. The Act enables the three universities of Oxford, Cambridge, and Durham, and their colleges, and the colleges of Winchester and Eton (a), to sell, enfranchise, and exchange lands, (b) to grant leases for agricultural, building, and mining purposes, and (c) to deal with the interests of lessees. Under the first head they are empowered to sell, enfranchise, and exchange through the medium and with the consent of the copyhold commissioners; under the second to grant agricultural leases for a term not exceeding 21 years at a rackrent, building and repairing leases for a term not exceeding 99 years, and mining leases for a term not exceeding 60 years; and under the third, to purchase the interests of lessees, either by payment of a gross sum of money or by an annual charge upon the lands: at the same time power is given them to raise the necessary sum or sums by mortgage, with the consent of the copyhold commissioners. Power is also given them to raise money for other purposes, such as the erection and improvement of university and college buildings, and of the buildings on their estates (§ 27); and the Act is expressly declared to extend to lands held by them in trust or for special endowments. The Mortmain Act of 9 Geo. II. c. 36, which has put considerable obstacles in the way of gifts of land or money to be laid out in land in England for charitable purposes, does not extend to the two universities of Oxford and Cambridge, or to colleges in the two universities, nor to gifts in favour of the scholars of Eton, Winchester, and Westminster. This statute contained a restriction as to the number of advowsons which a college in either of the universities was allowed to hold; but this restriction was removed by 45 Geo. III. c. 101, having been found, as the preamble to this statute sets forth, injurious to learning. These colleges can therefore now purchase and hold as many advowsons as they please.

A collegiate church is a church that has a college or chapter of canons, but no bishop, and yet is under the authority of a bishop. (See Ayliffe's Parergon,' p. 167.) These collegiate churches are sometimes simply called colleges. In the case of Manchester College, a mandamus was directed to the Bishop of Chester, as warden of Manchester College, to admit a chaplain. The bishop happened also to be visitor of the college. It was held by the King's Bench, that in the case of a spiritual corporation the jurisdiction was in that court, unless there was an express visitor appointed; and the court interposed in the present case because there was no separate visitorial power then existing, owing to the union of the wardenship and visitorship in the same person. (Strange, 797.) This case was afterwards provided for by an express Act, 2 Geo. II. c. 29.

As to the relation between the English universities and the colleges within their limits, and the nature of a college in the English universities, considered simply in itself, see UNIVERSITY in this DIVISION; and CAMBRIDGE and OXFORD, in the GEOGRAPHICAL DIVISION.

The statutes of all the old colleges in England are in Latin; and, indeed, with the exception of some comparatively modern endowments, probably all college statutes are in Latin. Those of Eton College, of Trinity College, Cambridge, and of St. John's College, Cambridge, which may serve as specimens of the statutes of such foundations, are printed in the Education Reports of the House of Commons, 1818; and now the old statutes of the colleges of Oxford and Cambridge have been printed by the commissioners for enquiring into the two universities, the former in 1853, the latter in 1852. For the early history and privileges of the universities, see, among others, Wood's Historia Antiq. Oxon,' Ayliffe's State of Oxford University,' and Dyer's 'Privileges of the University of Cambridge.'

Meiners (Geschichte der Enstehung und Entwickelung der Hohen Schullen,' &c., Göttingen, 1802, vol. i.) has given an interesting chapter on the origin of colleges in universities. The colleges in the University of Paris were the first institutions of the kind in Europe, though it is a mistake to suppose them older than the university itself.

The terms college and university have been often confounded in modern times, and indeed are now sometimes used indiscriminately.

ARTS AND SCI. DIV. VOL. III.

Some of the incorporated places of learning in the United States, which confer degrees, are called universities, and some are called colleges, though there is in fact no distinction between the two. Some of these institutions called colleges contain the schools or departments of arts, law, medicine, and theology; and some that are called universities contain only those of arts, law, and medicine. Some of these colleges are more limited as to the objects of instruction, but still confer degrees. If we look to the origin of colleges, and their connection with universities, it will be evident that the indiscriminate use of these terms is incorrect, and tends to lead to confusion. When an incorporated college, such as the College of Surgeons in London, is empowered to confer a degree or title after examination of candidates in a single department, some other name would be more appropriate. The word Academia, which is the most modern of all the terms applied to places of higher instruction, has been most usually applied to endowed corporate bodies which have for their object the improvement of some particular science or some particular branch of knowledge, in some cases with the power to confer degrees in such particular science, &c., and sometimes without this power. Yet the terms academia and university have also often been used, and now are used indiscriminately. (Meiners, vol. iv., 'On the Different Names of High Schools;' Huber and Newman, The English Universities,' vol. i.; and Savigny's 'Geschichte des Römischen Rechts im Mittelälter,' vol. iii., ch. 21. The history of the Scotch universities shows that the terms college and university were, both at the time of the foundation of these institutions and subsequently also, used with little discrimination; and this carelessness in the application of the terms had led to anomalies in their constitution, and no little difficulty in comprehending the history and actual constitution of these bodies. (See the Report of the Royal Commission of Inquiry into the State of the Scotch Universities,' printed 1831; and Malden's Origin of Universities,' London, 1835.) In France, the term college signifies a school, though the constitution of a French college is very different from that of our grammar-schools. It comes nearest, perhaps, to a German gymnasium. Of these colleges there are about 320, every large town having one of them. They are maintained by the towns, their heads and professors being paid out of the revenues of the communes. They are all under the superintendence of the University of France. There are also about 40 imperial colleges, in which the directors (administrateurs) and professors are paid by the state. The College Impériale of France, founded by Francis I., has above twenty professors, who lecture on the various sciences and the Oriental languages. (See Journal of Education,' No. III., ' On the State of Education in France.')

On the subject of colleges, from a legal point of view, the reader is strongly recommended to peruse an admirable argument on the rights of the fellows of Harvard University by the late Mr. Justice Story (Miscell. Writings,' p. 294).

COLLIDINE (CH,,N). An organic base found in bone oil. It is isomeric with xylidine.

COLLIMATION, ERROR OF. In most instruments the line of sight is supposed to have a certain relation to other parts. Thus in a transit telescope it ought to be perpendicular to the horizontal axis, in a circle or quadrant it should be in a horizontal or vertical direction when the reading of the limb is 0° or 90°. When this is not the case, the difference between the existing and required positions is called the error of collimation, which must be carefully ascertained, and be corrected or allowed for, or eliminated in the mode of conducting the observations. This will be particularly explained as each instrument comes under our notice. Many readers will have a general notion of the error of collimation from the mode in which a workman tries the truth of his square, or of the mason's level, which in principle is nearly allied to the methods of astronomers. When the telescope was originally applied to astronomical instruments, the mystery of ascertaining the true direction of a line which could not be mechanically examined, presented considerable difficulties to some observers. Hevelius of Danzig never could be induced to apply telescopic sights to his sextants or quadrants, and in consequence of this prejudice much of the labour of his long and active life was completely wasted. COLLIMATION, LINE OF, the line of sight in any astronomical or geodesical instrument. [CIRCLE.] Where a telescope is used, this name is given to the line joining the centre of the object-glass and the intersection of the fine wires or spiderwebs in its focus, this being the direction of any object which is there seen bisected by the observer.

COLLIMATOR, the name given by Captain Kater to his contrivance for determining the error of collimation in any principal instrument, without the reversal of the instrument itself. This reversal, troublesome in all large instruments, and in mural circles and quadrants, is forbidden by their construction. We shall give a sketch of Captain Kater's collimators and those antecedent to his invention, and a drawing and description of a level collimator, which on the whole we think best suited for common use. Where the adjustments, &c., mentioned are not described, the reader will find them in the article CIRCLE.

On referring to the description of each instrument, it will be seen that the determination of the error of collimation requires-1. A welldefined object, of which the direction remains unchanged; 2. A re

equally evident, that if, after the above correction is made, the object end o appears too high by n', that the true angle with the vertical is 90+n", or that the reading of the circle should show n" of depres sion. The different cases which may occur present no difficulty. If the collars are truly cylindrical and the level a delicate one, such a collimator should show the true horizontal point within 1". The telescope should not be very small, not less than 12 inches.

It would scarcely be just not to notice under this head an instrument by Roëmer, which has as much merit, as an invention, as any of these which we have described. It consists of two equal lenses fixed in a tube at a distance somewhat exceeding their focal length, with a system of wires in the focus of each, between the glasses. By applying the proper eye-piece at each end, the near wires, and consequently objects through the most distant object-glass, are made visible. The two object-glasses and the crosses of the wires being all adjusted in the same straight line, it is evident that, on looking in at each end of the tube, objects 180° apart will be seen on the crosses. Roemer called this tube an amphioptron, or reciprocal telescope, and used it for the transit adjustment in collimation of his rota meridiana. (Horrebow, 'Basis Astronomiæ,' p. 97.)

For further details, see Pearson's 'Practical Astronomy,' vol. ii. p. 446, plate xxi. COLLISION, IMPACT, or PERCUSSION OF BODIES, is that part of Dynamics in which are contemplated the effects arising from the striking against each other of two bodies, one or both of which are in motion, and answers to the choc des corps of French treatises.

It is usual to treat the first principles of this subject by supposing the bodies in question to be spherical; and for the following reason: When a body receives a blow, if it be free to turn as well as to move forward, a rotatory motion is, generally speaking, produced, as well as a motion of translation. But if the direction of the blow be in a line which passes through the centre of gravity, no rotatory motion is produced. Now if two equal spheres move upon a plane, it is obvious that when either strikes the other, the direction of the blow passes through the centre of gravity. Making use then of equal spherical balls, of the same or different weights, moving upon a level plane, let it be remembered that all conclusions apply equally to bodies of any form, having no rotatory motion, and striking each other in such a way that the line joining their centres of gravity passes through the point of contact at the moment when they strike.

The simple mathematical theory of impact proceeds, like other mechanical theories, upon suppositions which can only be approximately obtained in practice. For instance, if in the preceding supposition the level plane and the balls exercise any friction on each other, the consequence will be that the balls will begin to roll on the table, even though the blows which set them in motion pass through their centres. To the existence of this friction are due many phenomena which a game of billiards will present, and which will not result from the common theory. Let the table, then, be supposed to exert no friction on the balls, so that one of the latter, struck by a blow the direction of which passes through the centre, will move along the table without rolling.

Let us now suppose the ball A to be impelled directly towards an immovable obstacle, such as an upright ledge at the end of the table. On striking this ledge, the ball will, generally speaking, recoil more or less. Some substances will hardly give any recoil, while others will send the ball back with nearly the same velocity as that of its approach. This spring or elasticity is more easily measured than explained; it arises in the following manner: At the moment of impact, the ball compresses the part of the obstacle against which it strikes, which pressure continues until the reaction of the obstacle has destroyed all the velocity of the ball. At the same time the parts of the ball close to the point of impact have been compressed in a similar manner. If then there were no effort in the parts of the obstacle nor in those of the ball to recover their former position, the ball would remain at rest, close to the obstacle. If the recoil were complete, that is, if the parts of both bodies endeavoured to recover their position with a force equal to that which disturbed them, the recoil would rapidly but gradually create in the ball a velocity equal to that with which it approached. These two cases are the theoretical extremes which it is most probable no material bodies attain: in the first case they are said to be wholly inelastic, and in the second the elasticity is said to be perfect. But if only a fraction e of the velocity of approach be restored, then e is said to be the measure of the elasticity of the bodies.

If the striking bodies have spherical forms so that the contact may take place, at the first instant, in a point, their surfaces about that point will have their figures changed; and if the bodies have different degrees of hardness, an indentation may take place in that which is the least hard, the other penetrating to a certain distance in it. When the bodies are soft, like balls of wet clay, the change of figure produced by collision is manifest; but when two balls possess an elasticity which is nearly perfect, they so far recover their original figure after impact, that the change is not perceptible: it may be rendered evident, however, by covering one of the spheres with ink and suffering it to impinge on the other, the latter then receives a stain which, instead of being a point, is a circle of sensible magnitude; and this proves that the surfaces must have been flattened at the point of impact.

Impact has been termed a "pressure of short duration;" but practically there is a great difference between the effects of pressure and impact: thus, a very large weight will be required to press a nail into a block of wood, which may be readily driven into it by a small hammer; and the reason is, that a longitudinal compression of the nail towards the head takes place, which is followed by restitution, and these actions follow each other successively, and the nail enters by a kind of vermicular action, like that of a worm progressing through the earth.

Also, when impact is employed to communicate motion to one body relatively to another, the effect produced depends greatly on the immobility of the latter; thus, many more blows will be required to drive a nail into a loose board, than would suffice if the latter were fixed; although, in certain cases, as in the breaking of minerals, &c., the effect of impact is diminished by a firm support. Here, probably, the effect of momentum on the successive particles is interfered with by a contrary momentum generated by restitution.

In order to account for the effect of percussion in impelling a body, a wedge for example, being much greater than that of mere pressure,it may be observed that both effects depend on the product of the mass of the impelling body and its velocity: but, when a body moves in consequence of pressure, the velocity is extremely small; therefore, in order that the effect of simple pressure may be equal to that of percussion, the mass imposed must be very great. It is evident, however, from what has been said, that the two forces are of the same nature. It should be added, here, that the shock produced in a material, when divided by a wedge, or penetrated by a nail, either of these being driven with a force produced by a sudden blow of a hammer may, by displacing the particles of the material, diminish their cohesive power; and this may be, in part, the reason that the effect of percussion often exceeds that of a weight many hundred times greater than that of the hammer.

The force of elasticity is very different in different bodies: spheres of glass are those in which the force of restitution (after impact) approaches nearest to the force of compression; and, in such spheres, the ratio between the forces is as 15 to 16: in spheres of ivory the ratio is as 8 to 9; and in spheres of steel, as 5 to 9.

The bodies upon which experiments on collision are usually made are generally of a spherical form; in order that when they impinge upon one another directly it may be indifferent at what part of the surfaces of the bodies the contact takes place: the bodies are usually suspended by a string or rod from fixed points; and they are made to impinge upon one another while describing circular arcs, in a vertical plane, about the point of suspension. The absolute momentum, or quantity of motion in a body, is represented by the product of its mass and the velocity with which it is moving: but the effects of the collision of two bodies depend on their relative velocity, or that with which they approach to, or move from, one another; this is consequently the sum of the absolute velocities when the bodies, in approaching each other, move in opposite directions, and the difference when they move in the same direction.

The principles upon which are determined the velocities after impact of different balls which strike one another are as follow:—

1. If two perfectly inelastic balls move towards each other in opposite directions, and with velocities inversely proportional to their weights or masses, they will destroy each other's velocities and remain at rest. Thus if A were twice as heavy as B, but if в moved twice as

MOTION, LAWS OF.] Let a be the velocity of A, and b of B; then A and B being expressed in the same units of weight, and a and b in the same units of length and time, the preceding condition is fulfilled when AaBb.

2. If the same velocities be added to or taken from both balls, so that their rate of approach is not altered, the forces exerted in the shock will not be altered, nor will the rate of recess after the shock. Thus a cannon-ball rebounding from a wall, both having the motion of the earth, strikes with the same force and rebounds in the same manner

the earth were at rest.