COLOURS. 



COLUMBARIUM. 



42 



(.1/a/ra sylvestrii) ; mallow being rendered in French by the word 

 mauve. 



The colouriny matters of jloicers are owing, according to Fremy and 

 Cloez, to two principles, cyanine and xanthine. The blue tints are 

 produced by cyanine ; the rose tints by cyanine in the presence of an 

 acid. Xanthine furnishes the yellow shades, becoming brown hi the 

 presence of alkalies from formation of xanthclne. [CYANINE, and 

 XANTHINE. 



The dark colourint/ matter of the eye is said to be due to a substance 

 called melaninc. [MELANINE.] 



Colouring matter of blood. [HjBJiATOsnj.] 



For the methods of fixing colours on fabrics, see DYEIXG and 

 CALICO-PRINTING. 



COLOURS. The word colour is used in many different ways. 

 Besides its original meaning, in relation to the tints of r.vys of light, it 

 has gradually come to be applied to the substances by which those 

 tints are imitated. 



Painter's colours, for house-painting and similar purposes, are mostly 

 prepared from mineral substances (white lead, red lead, umber, ochre, 

 Ac.) ground up with linseed oil and turpentine to the state of a thick 

 liquid. It would, perhaps, scarcely be supposed that ' Painters' 

 Colours ' appear in the Board of Trade tables, as an article of export, to 

 the value of 150.000/. to 200.000/. annually. 



The oil colours for artists are more carefully prepared than those 

 for house-painting. They used to be sold tied up in small bladders ; 

 but an ingenious and more convenient arrangement is now adopted. 

 Mr. Winsor's envelopes for colours, patented in 1840, consist of small 

 metal or glass tubes, open at both ends, and provided with elastic 

 pistons or plugs of cork or some similar material. The piston has a 

 worm or nut in its centre, which corresponds to a screw attached to a 

 handle rather larger than the tube. The open ends of the tube are 

 covered with small metallic plates having holes in their centres. 

 When the colour is placed in the tube, the arrangement of the appa- 

 ratus is such as to keep the air from acting on it ; and when any is 

 required to be used, the screw is turned round, the piston is pressed 

 down, and a little colour exudes from the lower end. These envelopes, 

 like those of bladders, have however been superseded by a very in- 

 genious contrivance, which hag been generally adopted by artists, Mr. 

 Rand's Collapsible Colour-tubes. These tubes were made the subject of 

 a patent in 1842 ; the objects of which were to introduce a mode of 

 punching out by dies the thin pieces of tin of which the tubes arc 

 made ; and to make a screw cap at the mouth of the tube, to prevent 

 leakage. These little tubes, by a gentle squeeze, are made to yield the 

 colour at one end just in sufficient quantity for use. 



Water-colours for artists include both vegetable and animal as well 

 as mineral substances, and like the oil colours, are prepared with very 

 great care. [COLOURING MATTERS.] They are prepared dry in cakes ; 

 in a slightly moist state in small cups of porcelain, gutta-percha, or 

 tin; and in the collapsible tubes at first only used for oil-colours. 

 From the care required in their preparation, water-colours of good 

 quality were only obtainable at a comparatively high price, but the 

 London Society of Arts has been instrumental in inducing manufac- 

 turer to produce shilling boxes of water colours applicable to the 

 wants of students in schools of design, and other persons in humble 

 life, of a character equal to those previously obtainable at a much 

 higher rate. 



Mr. Smith of Blackford communicated to the Royal Scottish Society 

 of Arts, a paper showing that when chromate of lead is mixed with 

 muriate of ammonia, and subjected to the action of heat, a sub 

 stance is obtained of a different colour from either of the matters used 

 If the proportions of the substances be varied, and different degrees o 

 heat applied, distinct colours and tints will be the result. Thus 

 when 5 parts of chromate of lead, and 1 part of muriate of ammonia 

 are heated to redness in a crucible, a red colour is obtained ; a blue 

 colour is formed by heating 10 parts of muriate of ammonia, and 1 par 

 of chromate of lead to ebullition ; and a green is produced when the 

 last mixture is heated nearly to redness. By employing various pro- 

 portions of the substances, and different degrees of heat, a great variety 

 of tints are formed scarlet, orange, brown, blue, purple, green, yellow 

 awl others. It is conceived by the discoverer that these properties 

 may lead to useful applications in the arts. 



The progress of chemistry naturally enlarges the list of substance 

 from which colours can be obtained ; and we find numerous patent 

 bearing on this subject. A few years ago it was hoped that pigments 

 for house-painters might be obtained from the residuum found in 

 galvanic latteries, after the decomposition of those metallic compounds 

 concerned in producing the galvanic action ; the pigments are cer 

 tainly produced, and batteries have been lined expressly to this end 

 but the electro-colours, as they are called, have scarcely become 

 marketable commodity. 



COLOURS ACCIDENTAL. [ACCIDENTAL COLOURS ; LIGHT.] 

 COLOURS COMPLEMENTARY. [ACCIDENTAL COLOURS; LIGHT. 

 COLOURS OF PLATES. [LiOHT.J 



COLTSFOOT, the name given, owing to th shape of the leaves, t< 

 the compound indigenous plant, called by botanists Tumilaijo Farfara 

 It* Latin name has reference to its reputed virtues as a means o 

 driving away coughs. If it be, as conjectured by Dr. Sibthorp an 

 others, the B^x'ov of the Greeks, its fame descends from a very remott 



eriod ; but its sensible properties do not seem to justify its character, 

 'he flowers and leaves are used in almost every way and means possible, 

 oth fresh and dry. The flowera are slightly odorous, and very slightly 

 itter, the leaves are more bitter ; the latter somewhat mucilaginous, 

 'hese when young, boiled, form a good spring vegetable, which might 

 e more frequently used, especially by the poor. 



No analysis (quantitative) of coltsfoot has been made, but the chief 

 onstituents are : mucilage, bitter extractive, tannic acid, colouring 



matter, salts, and woody fibre. 



The properties are feebly tonic, demulcent, and emollient ; on the 

 atter account the leaves are sometimes used as an external application 

 or poultices or fomentations. The vaunted properties of coltsfoot 

 nd no credence with the educated, and it only retains its reputation 



as a popular remedy. Hence it is chiefly sold as a nostrum, in the form 

 f lozenges, which, when harmless, have their virtues increased by 



adding extract of liquorice and other demulcents, but which are often 

 endered hurtful and even destructive by morphia and other powerful 



narcotics. Essence of coltsfoot is a stimulating compound of balsam 

 if tolu, compound tincture of benzoin, with a double quantity of recti- 

 led spirit of wine. Most improper at the beginning of colds, the root 

 leserves attention as an astringent of considerable power. 



COLUMBA NO'ACHI (constellation), the dove of Noah, a con- 

 tellation formed by Halley, close to the hinder feet of Canis Major. 

 ?he following are the principal stars in this constellation : 



Chiracter. 



I 

 a 

 I 

 1 



No. in Catalogue 



of British 



Association. 



1739 



1802 



1878 



1922 



Magnitude. 

 4 

 2 

 3 

 4 



COLUMBAHIUM, a place of sepulture used for the ashes of tlie 

 tomans after the custom of burning the dead had been introduced 

 among them. It is usually a square or oblong room, the walls of which 

 are pierced with small cells or niches for holding the urns which con- 

 Plan of Columbarium, discovered in the gardens of the Villa Doiia ramflli at 

 Rouie. 



Columbarium B .to 

 a larger cl. 



Section of Columbarium B. 



tained the ashes of bodies which had been subjected to burning. The 

 word columbarium signifies a dovecote; and its application to the 



