Colours vary in hue, in purity, and in luminosity. The hue, determines the name of the colour-e.g. vermilion, scarlet; the purity or absence of admixture with white light determines its richness-vermilion reflects 80 per cent. of red light mixed with 20 of white; the luminosity or brightness determines the shade or tone of colour. Interfere with any of these and the impression produced upon the eye is modified. Take for example a definite red light, saturated or unadulterated with white light, such a red as may be found in the spectrum; progressively lower its purity by mixing it with white light-it becomes brighter, but passes through light red and pink to pinkish-white tints; lower its luminosity by mixing with black-it passes through terra-cotta tones to brown, which is a dull red; interfere with both purity and luminosity by mixing with various greys-it goes through russets and maroons, the so-called tertiary colours. Any colour in nature can be matched either by a spectral colour or by a purple, treated in this way; and for each such modification of the original colour there will be a different complementary.

The colour of transparent objects is due to Selective Absorption. Look at a red object through a suitable piece of greenish-blue glass, and it appears black; the greenish-blue glass is opaque to the light proceeding from the red object. Hold the same piece of glass up to the sky, and the red lights, which are components of the white light of day, are cut off; what passes through produces a sensation of greenish-blue. The red, which is cut off by absorption, and the greenishblue, which passes through, are complementary to one another-both being really complex, not monochromatic. The colour of a transparent body will also apparently depend upon the thickness of the layer examined: a thin layer of iodine-vapour absorbs all the constituents of visible white fight except blue and red; it therefore appears in daylight to be purple; a thicker layer effects the complete absorption of the red but not that of the blue, and a thicker layer of iodine-vapour therefore appears blue. If looked at in red light, a thin layer of iodine-vapour appears red, while a thick layer will present the blackness of opacity.

Before a non-luminous object can be seen otherwise than by transmitted light it must reflect light; if it reflect none it will appear black; a dustless pool in a mountain-hollow, a liquid in a deep black vessel, may reflect no light to the eye of the observer, and will appear black. (Black is the negation of colour, because it implies that there is no sensation of light; gray, produced by mixing white and black, is white deficient in luminosity). Let the pool become turbid, and there will be some light reflected towards the observer. A coloured liquid in a deep black vessel will have its colour revealed by sprinkling a white powder into it. White light (daylight) enters the liquid; it is reflected in all directions by the white powder; but it is in part absorbed by the liquid, which accordingly appears coloured. Of precisely the same kind is the reflection of light by a solid object. Bodies allow light to traverse them to a very small depth, and then the light is, by internal reflection, turned back in all directions; absorption, meanwhile, comes into play, and the result is that the object appears to have a definite colour, the purity of which is marred by surface-reflection. The white light reflected from the surface of a metal masks its true colour, which is brought out by repeated reflection. Gold is deep orange; copper, scarlet; silver, yellowish-bronze; brass, a rich golden red.

If the light supplied to an object do not contain those kinds of light which it can reflect, the object will appear black or colourless; a bunch of flowers

COLOUR-BLINDNESS

looked at by the yellow light of burning sodium or of a spirit-lamp with common salt in the wick, will all appear black or colourless except those which are yellow. Surface-reflection modifies the result.

There is one class of cases in which colour is not due to absorption. A haze is blue if its particles be fine enough: if it be composed of coarse particles it at once reflects white light in all directions; but fine particles cause repeated reflection, and at each reflection the reflected light becomes bluer; because those rays which would have been most refracted (the blue and violet) are in fact most largely reflected. The colour of the sky is that of a haze, reflecting light downwards; if there were no dust-haze or water-haze above us, the sky would be black. The light which is not reflected from such a haze is either transmitted through it, yellower or redder in colour, or else it is entirely absorbed. The sun thus appears yellower than it would do if our atmosphere did not intervene. See also DICHROISM, INTERFERENCE, IRIDESCENCE, LIGHT, OPTICS, PHOSPHORESCENCE, PLEIOCHROISM, RAINBOW, SPECTRUM, DYEING, and the articles on the several colours; and for further information, consult Colour by A. H. Church (Lond. 1887), and Colour by C. T. Whitmell (Cardiff: 1888). For Heraldic Colours, see HERALDRY; for the Ecclesiastical Colours, VESTMENTS; and for Colour in Animals, PIGMENT.

Colour-blindness, a term introduced by Sir David Brewster to denominate a defect of vision owing to which some persons are unable to distinguish certain colours correctly. It is also called Achromatopsia (Gr.) and Daltonism, from Dalton the chemist, who suffered from the defect, and who gave the first detailed description of it (1794). Of this defect there are several degrees, classified as follows (by Holmgren of Upsala): (1) Total colourblindness, where there is no perception of colours as such, but only of gradations of light and shade; (2) Complete partial colour-blindness, where some bright colours, different in different cases, are confused with each other, though other colours are correctly perceived; (3) Incomplete partial colourblindness, where bright colours are recognised, but more delicate shades are confused. The first form is rare, and generally, perhaps always, associated with other defects in the eyes; the third is probably common, though not of great importance; to the second attention will mainly be directed here.

With regard to the classification of the cases of complete partial colour-blindness authorities are not agreed; the important practical point is that in the vast majority red and green are the colours confused. Some confuse a bright red with a green that appears to a normal eye a much lighter colour; some with a green that appears darker. But if suitable tests be applied it will be found that they do not distinguish red and green as such. Experience, however, and observation of the different apparent brightness of ordinary reds and greens, enables them to distinguish between them in most cases with wonderful accuracy, so that they may remain unconscious of their defect till some striking mistake, or the application of a systematic test, reveals it. Cases of colour-blindness for yellow and blue, if they occur at all, are extremely rare. Experience proves that this defect is generally hereditary, and is quite incurable. The eyes respect; no difference has been detected in their may be, and usually are, perfect in every other structure, either during life or after death; so the cause of their defective perception remains absolutely unknown.

Numerous careful and extensive researches both in various countries of Europe and in the United States have shown that this defect is present

served in the army 1829-34, and became a supreme authority on sport in Scotland. The famous record of his experiences, The Moor and Loch, published in 1840, was much extended and improved in the 4th (1878) and 5th (1884) editions. Rocks and Rivers appeared in 1849; Salmon Casts and Stray Shots, 1858; and Sporting Days, 1866. He died at Edinburgh, 27th May 1885.

Colquhoun, PATRICK, born at Dumbarton, 14th March 1745, became provost of Glasgow in 1782, went to London in 1789, and in 1792 became a police-magistrate there. He was indefatigable in forwarding administrative legislation, educational and commercial reforms, wrote innumerable pamphlets, and published two important worksWealth, Power, and Resources of the British Empire Police of the Metropolis (1795); and Population, (1814). He died 25th April 1820.

Colston, EDWARD. See BRISTOL.

Colt, SAMUEL, inventor, born in Hartford, Connecticut, in 1814, ran away to sea in 1827, and about 1832 travelled over a large part of America, delivering lectures on chemistry by which he obtained the funds required to prosecute his invention. In 1835 he took out his first patent for a revolving pistol, which after the Mexican war was adopted as a regular weapon for the United States army, and since then has been adopted universally. Colt expended over $2,500,000 on an immense armoury in Hartford, where he died 10th January 1862, and where his widow erected a handsome Episcopal church to his memory. See REVOLVER.

Colt's-foot. See TUSSILAGO.

Coluber, a genus of non-venomous snakes, of almost world-wide distribution. It forms a type of the family Colubrida, in which the common Ringed English Snake (Tropidonotus natrix) is also included. The Esculapian Snake (Coluber aesculapii), so familiar from ancient times as a symbol of medicine, is the best known species. It is very common in Italy, is the species of the Schlangenbad, and is widely distributed in Europe. It is of a predominantly brown colour, attains a length of 4 or 5 feet, and is readily tamed. All the members of the family are very typical, exhibiting few deviations from the general snake structure. See SNAKE.

Columba, ST-called also ST COLUM-CILLE (Columba of the Churches,') and ST COLM-was born (it is believed at Garton, County Donegal) in the north of Ireland, on 7th December 521. He was of high descent, his father Fedhlimidh, of the powerful tribe of the Cinel Conaill, being a kinsman of several of the princes then reigning in Ireland and in the west of Scotland; and his mother, Eithne, was also of royal blood. After studying under St Finnian at Moville on Strangford Lough, and under another St Finnian at Clonard (where he had as companions St Comgall, St Ciaran, and St Cainnech), he spent some time near Dublin; but in 546, when no more than twenty-five, he returned to the north and founded Derry, and, six or seven years afterwards, Durrow, the greatest of all his Irish monasteries. The belief that he had caused the bloody battle of Culdremhne in 561 led to his excommunication by an Irish ecclesiastical synod, and practically to exile from his native land.

Setting out in 563, when in his forty-second year, and accompanied by twelve disciples, he found a resting-place in the little island of Hy or Ioua, now better known as Iona (q.v.), or I Colum-cille, and having planted a monastery there, he set himself to the great work of his life, the conversion of the Pictish tribes beyond the Grampians. His missionary efforts were highly successful, but unfortu

COLUMBA

nately very little is known of the way in which he effected his purpose. Bede speaks simply of his preaching and example.' Adamnan, extolling his gift of miracles, tells how the gates of the Pictish king's fort near Inverness burst open at his approach, and how, as he chanted the 45th Psalm, his voice was preternaturally strengthened so as to be heard like a thunder-peal above the din and clamour by which the Pictish magicians tried to silence his evening prayer under the walls of the Pictish palace. We get another glimpse of his missionary footsteps from the Book of Deer (q.v.), which records how Colum-cille and Drostan, the son of Cosreg, his disciple, came from Hy, as God had shown them, to Aberdour,' freedom for evermore;' how they came after that in Buchan; how 'Bede, a Pict, was then highsteward of Buchan, and gave them that town in to another town, and it was pleasing to Colum-cille, for that it was full of God's grace; and he asked of the high-steward Bede that he would give it to him, but he gave it not; and, behold, a son of his took an illness, and he was all but dead, and the highsteward went to entreat the clerics that they would make prayer for his son that health might come to him; and he gave in offering to them from Clochin-Tiprat to Cloch-Pette-mic-Garnait; and they made the prayer, and health came to him.' In some such way as this St Columba and his disciples seem to have traversed the Pictish mainland, the Western Islands, and the Orkneys, establishing humble monasteries whose inmates ministered to the religious wants of the people. The parent house of Iona exercised supremacy not only over all those monasteries, but over all the monasteries that St Columba had built in Ireland, and the northern provinces of England. Thirty-four over those that were founded by his disciples in years appear to have been spent by St Columba in raising up and perfecting his ecclesiastical system in Scotland. But the labour did not so wholly engross him but that he found time for repeated voyages to Ireland, and for a visit to Glasgow, where St Kentigern or Mungo was restoring Christianity among the Welsh or British tribes of Cumbria and Strathclyde. The health of St Columba seems to have begun to fail in 593, but his life was prolonged till he reached his 76th year, when he breathed his last as he knelt before the altar of his church in Iona a little after midnight, between the 8th and 9th June 597. He was buried within the precinct of his monastery, and his bones -which were afterwards enshrined-the stone pillow on which he slept, his books, his pastoral staff, and other things which he had loved or used, were long held in great veneration.

Whether any original composition of St Columba's still survives is doubtful, though an Altus published by Dr Todd in the Liber Hymnorum, and republished by the Marquis of Bute in 1882, has been ascribed to him by unbroken tradition. Be this as it may, he was certainly eminent as a transcriber. Adamnan tells us that on the night before his death he was engaged on a transcript of the Psalter, and in the Annals of Clonmacnois it is stated that he (Columba) wrote three hundred books with his own hand. which books have a strange property, which is that if they or any of them had sunk to the bottom of the deepest waters they would not lose one letter, or sign, or character of them, which I have seen tried, partly by myself on that book of them which is at Dorowe.' The two existing specimens of St Columba's work, both preserved at Dublin, are the Book of Durrow just mentioned, and the Psalter known as the Cathac or Battler. This name it has received from the custom of bearing the relics of the ancient Celtic saints into battle as sacred

COLUMBAN

victory-bringing ensigns. was also used in this way.

St Columba's crosier

St Columba's character was very complex, but marked in all things by enthusiasm and earnestness. Warlike and aggressive by temper and descent, as well as from the spirit of the times, he was naturally more inclined to action than to melancholy, and yet he had a tendency to expatiate amid visions; and though his disposition was prevailingly austere, he had frequent gleams of tenderness and kindness. 'Angelic in appearance,' says Adamnan, graceful in speech, holy in work, with talents of the highest order and consummate prudence, he lived during thirty-four years an island soldier. He never could spend the space even of one hour without study, or prayer, or writing, or some other holy occupation. So incessantly was he engaged night and day in the unwearied exercises of fasting and watching, that the burden of each of these austerities would seem beyond the power of all human endurance. And still in all these he was beloved by all; for a holy joy ever beaming on his face revealed the joy and gladness with which the Holy Spirit filled his inmost soul.'

In the ecclesiastical system of St Columba as in that of Ireland, the church was essentially monastic with neither a territorial episcopacy nor anything like presbyterian parity, but the same anomalous position of the episcopal order. The bishops were under the monastic rule, and as such were in respect of jurisdiction subject to the abbot, even though a presbyter, as the head of the monastery;' but while the power usually reserved to the episcopate was thus transferred to the abbatial office, the episcopal orders were fully recognised as constituting a grade superior to that of the presbyters,' and as carrying with them the functions of ordination and celebration of the eucharist according to the episcopal rite. St Columba himself, as well as his followers generally till the year 716, kept Easter on a different day, and shaved their heads after another fashion than obtained in other parts of Western Christendom. But with these exceptions, their creed and rites appear to have been substantially the same.

The chief authority for the life of St Columba is the account written by St Adamnan (q. v.), who was abbot of Iona from 679 to 704, and who incorporated in his work an earlier life by Cuimine (abbot, 657-669). Of this Dr Reeves published an edition in 1857 for the Bannatyne Club, and it has since been re-issued in the Scottish Historian' series (1874). See also Smith's Life of St Columba (Edin. 1798); Lanigan's Ecclesiastical History of Ireland (1822); Father Innes's History of Scotland (Spalding Club, 1853); Montalembert's Monks of the West, vol. iii.; Forbes's Kalendars of Scottish Saints (Edin. 1872); and Skene's Celtic Scotland, vol. ii. (Edin. 1877).

Columban, or COLUMBANUS, ST, one of the most learned, eloquent, and devoted of the many missionaries whom Ireland sent forth to the Continent during the Dark Ages, was born in Leinster in the year 543. Having studied under St Comgall, in the great monastery of Bangor, on the coast of Down, he passed over to France, in his fortieth year, accompanied by twelve companions, and founded successively the monasteries of Anegray, Luxeuil, and Fontaine, in the Vosges country. His adherence to the Irish rule for calculating Easter involved him in controversy with the French bishops in 602; and a few years later, the courage with which he rebuked the vices of the Burgundian court, led to his expulsion, largely at the instigation of the notorious Brunhilda, the king's grandmother. After various travels and adventures, and having for a year or two settled at Bregenz,

near the Lake of Constance, he passed into Lombardy, and in 612 founded the famous monastery of Bobbio, in the Apennines, where he died on the 21st November 615. His life, written within a century after his death, by Jonas, one of his successors in the abbacy of Bobbio, has been repeatedly printed. The writings of St Columban, which are wholly in Latin, consist of a rule for the government of his monastery, six poems on the vanity of life, several letters on ecclesiastical affairs, seventeen short sermons, and a commentary on the Psalms (first published at Rome in 1878). The most complete edition of his works is in Patrick Fleming's Collectanea Sacra (Augsburg, 1621; Louvain, 1667), followed by the Bibliotheca Patrum, and Migne's Patrologia Cursus (1844). The town of San Colombano, in the province of Milan, takes its name from the Irish monk, as the town and canton of St Gall (q.v.), in Switzerland, perpetuate the name of the most favoured of his disciples. See the Vita by his successor Jonas of Bobbio, Montalembert's Monks of the West, and Wright's Biographia Literaria.

Columba'rium (Lat.), a dovecot or pigeonhouse, which probably differed little in form from those in modern use, but was sometimes built on a much larger scale, as we read in Varro of as many as five thousand birds being kept in the same house. The same name was applied to the niches or pigeon-holes in a particular kind of sepulchral chamber in which the urns (olle) containing the ashes of dead bodies burned were deposited. Each niche usually contained two urns, and the four walls of the sepulchre sometimes contained as many as one hundred niches or more. The names of the persons were inscribed underneath. Tombs of this description were chiefly used by great families for depositing the ashes of their slaves and dependants.

Columbia, the name of nearly thirty places in the United States, of which the most important are: (1) The capital of South Carolina, at the head of navigation on the Congaree River, 130 miles NNW. of Charleston by rail. The town is regularly built, with several handsome streets, and contains a fine granite state-house ($3,000,000) and other official buildings. It is the seat of a Presbyterian theological seminary, and of the university of South Carolina (1806). Pop. (1890) 15,353. (2) A borough of Lancaster county, Pennsylvania, on the Susquehanna, which is here crossed by a railway bridge, 80 miles W. of Philadelphia, with several iron-furnaces and rolling-mills, and manufactures of machinery, flour, &c. Pop. (1890) 10,597.-(3) The capital of Maury county, Tennessee, on the Duck River, 45 miles SSW. of Nashville by rail, with manufactures of ploughs, furniture, and flour. Pop. (1890), with suburbs, about 7000.-(4) The capital of Boone county, Missouri, 24 miles E. of Boonville, with manufactures of flour, tobacco, and woollens. It is the seat of the state university (1840), which is open to both sexes, and has some five hundred students and fifteen professors. Pop. (1890) 3985.

Columbia, or OREGON, after the Yukon the largest river on the west side of America, rises in British Columbia, on the west slope of the Rocky Mountains, near Mounts Brown and Hooker, in about 50° N. lat., has a very irregular course, generally south-west, through Washington, forms the northern boundary of Oregon for about 350 miles, and enters the Pacific by an estuary 35 miles long and from 3 to 7 wide. Its estimated length is 1400 miles. The area drained by this stream and its affluents, of which the largest are Clarke's Fork and the Snake River (with very remarkable cañons), has been computed at

298,000 sq. m. The river is broken by falls and rapids into many separate portions, and the ingress and egress are embarrassed by a surfbeaten bar. Still, it is open to steamboat navigation from its mouth to the Cascades (160 miles), and goods are carried past the obstruction, for 6 miles, by railway; the next reach, of 50 miles, extends to Dalles, where another railway, of 14 miles, has been constructed past the Great Dalles channel; and immediately above this are two sections, of 185 and 250 miles respectively, navigable for small steamboats. The extraordinarily abundant salmon-fisheries of the Columbia have been largely developed. There are a number of canneries, mostly near the mouth of the river, and in the fifteen years ending 1881 the annual export of canned salmon rose from 4000 to 530,000

cases.

Columbia, BRITISH, is a province of the Dominion of Canada, bounded in the N. by the 60th parallel of latitude; on the S. by the United States; on the W. by the Pacific Ocean and part of Alaska; and on the E. by the provisional districts of Alberta and Athabasca (Northwest Territories). The area of the province is recorded as 383,300 sq. m., including Vancouver Island (14,000 sq. m.) and Queen Charlotte Islands (5100 sq. m.). The last named consist of a group of about 150 islands, their united length being 156 miles, lying about 200 miles north-west of Vancouver Island. British Columbia was practically under the control of the Hudson Bay Company until 1858, when owing to the discovery of gold, and the consequent immigration of miners, it was made a crown colony. Vancouver Island was made a crown colony in 1849, and leased to the Hudson Bay Company for ten years. The two colonies were united in 1866, and the province joined the Canadian Confederation on 20th July

1871.

Be

The scenery is rugged and picturesque, being diversified with mountain, lake, and river. tween the western slopes of the Rocky Mountains (highest peaks, Mount Brown, 16,000 feet, and Mount Hooker, 15,700 feet) and the sea the whole of the space is occupied to a considerable extent by spurs and outlying groups belonging to that chain. In the immediate vicinity of the coast these form a nearly continuous line of mountains of moderate elevation, known as the Cascade Range. The territory is well watered by rivers which have their origin in the highlands, and find their way into the Pacific Ocean. Of the rivers the most important is the Fraser, 800 miles long, and 600 yards wide at its principal outlet in the Gulf of Georgia, the arm of the sea which separates Vancouver Island from the mainland. Other rivers in British Columbia are the Columbia (which has only its upper portion within the province), the Stickeen, the Skeena, and the Finlay. Many varieties of climate are found in this province. That of Vancouver Island and the coast of the mainland is very similar to that of the south of England. The interior of the mainland is divided as to climate into three zones-the south, the middle, and the north. The south lies, for the most part, between the 49th and 51st parallels N. lat., and the fall of rain and snow in this district is slight. It contains a good deal of grass or pasturage lands, but for arable purposes the land requires irrigation. Between 51° and 53° N. lat. is the middle zone; it includes the high mountains west of the Columbia, contains dense forests, and the rainfall is considerable. The north zone lies between 53° and 60° N. lat.

Population.-In 1891 the population according to the census returns was 92,767 (including some 30,000 Indians), it having increased from 33,586 in

1871 and 49,459 in 1881. The principal towns on Vancouver Island are Victoria, the capital (pop. 1881, 5925; 1891, 16,841), and Nanaimo (5000). On the mainland there are New Westminster (1891, 6641), formerly the capital of British Columbia, and Vancouver (1891, 13,685), the terminus of the Canadian Pacific Railway. The Indians of British Columbia are as a rule law-abiding and industrious. The coast Indians live largely by hunting and fishing, and are also employed in connection with the lumber industry and the salmon-canneries. The province is represented in the Dominion Senate by three members, and in the House of Commons by six. The provincial government is administered by a lieutenant-governor, appointed and paid by the Dominion, and a Legislative Assembly of 27 members, elected by the inhabitants. Education is compulsory and free between the ages of seven and twelve.

The province is not likely to become an agricultural country, but there is a considerable area of land available for arable and pastoral farming both on Vancouver Island and on the mainland in the river-valleys. On the west of the island but little arable land is to be found. The principal settlements are upon the east and south coasts, but good land is still to be found on the east coast, and also on the north. The rich valley of the lower Fraser, or New Westminster district, is the largest compact agricultural area on the mainland. There are large tracts of alluvial soil farther up the Fraser and along some of its most Of the total area (say important tributaries. 250,000,000 acres) only about 500,000 acres are as yet occupied. The fruit-growing industry is expected to become important, but it is still in its infancy. The principal industries of the province are connected with the mines, the fisheries, and the forests. The minerals form one of its chief resources. Gold, coal, silver, iron, copper, galena, mercury, platinum, antimony, bismuth, molybdenum, plumbago, mica, and other minerals have been discovered in different parts, copper being very widely distributed. Gold was produced in 1887 to the value of $693,709, and the value of the output from 1858 to 1887 was $50,983,226. The quartz-mines have hardly been touched; all the metal hitherto secured has come from the alluvial deposits. Coal and lignite are known to exist in many parts of the mainland. At Nanaimo, on Vancouver Island, there is a large coal-field, and the mines are the most important on the Pacific coast. Over 413,000 tons were raised in 1887, and 334,839 tons were exported, largely to the United States. Nanaimo is connected by rail with Esquimalt, the headquarters of the Pacific squadron, and the site of a large graving-dock. Iron is found in many localities. The fisheries of the province are most extensive, but excepting the salmon-fishery have not yet been developed. The seas, bays, gulfs, rivers, and lakes of the province swarm with food-fishes. There are numerous salmon-canneries in operation. The fursealing industry in the Pacific is also a valuable one. But little timber has yet been cut, notwithstanding the immense forests of magnificent trees that abound in British Columbia. The important commercial trees are the Douglas pine, Menzies fir, yellow cypress, and maple, and the shipments so far have been chiefly to Australia, South America, the Cape, and China.

The value of the imports in 1887 was $3,626,139, of which $793,434 came from Great Britain, and $2,059,035 from the United States. The exports were valued at $3,371,841. To Great Britain the exports were $810,977, and to the United States, $2,220,092.

Until the completion of the Canadian Pacific Railway in 1885, British Columbia was isolated