AND OF THE PHYSICAL SCIENCES. 



47 



tact. The two great iron bars being made magnetical by position, the interposed bar 

 of steel will, therefore, when thrown into a state of vibration by percussion, receive a 

 portion of their magnetism. In like manner, a magnet, when struck in the air with a 

 piece of flint, or upon a body of inferior magnetic quality, will have its magnetism 

 diminished. ^ 



MISCELLANEOUS. 



LAWS OF HARMONIOUS COLOURING. 



According to the theory of Sir Isaac Newton, there are seven primary colours, 

 viz. violet, indigo, blue, green, yellow, orange, and red. Artists, however, have 

 long considered that there are only three, namely, red, yellow, and blue ; and this 

 opinion has recently been adopted by Sir David Brewster and other philosophers. 

 It is quite certain that, by a combination of these three colours, every other can be 

 made. 



" If we look steadily (says Mr Hay *) for a considerable time upon a spot of any given 

 colour, placed on a white or black ground, it will appear surrounded by a border of 

 another colour. And this colour will uniformly be found to be that which makes up 

 tlie triad; for if the spot be red, the border will be green, which is composed of blue 

 and yellow; if blue, the border will be orange, composed of yellow and red; and if 

 yellow, the border will be purple, being in all cases the complement of the three 

 colours called by artists homogeneous. 



" It is well known to all who have studied music, that there are three fundamental 

 notes, viz. C, E, and G, which compose the common chord, or harmonic triad, and 

 that they are the foundation of all harmony. So also there are three fundamental 

 colours, the lowest number capable of uniting in variety, harmony, or system. 



*'By the combination of any two of these primary colours, a secondary colour of a 

 distinct kind is produced; and as only one absolutely distinct denomination of colour 

 can arise from a combination of the three primaries, the full number of really distinct 

 colours is seven, corresponding to the seven notes in the complete scale of the 

 musician. Each of these colours is capable of forming an archeus, or key, for an 

 arrangement, to which all the other colours introduced must refer subordinately. This 

 reference and subordination to one particular colour, as is the case in regard to the 

 key-note in musical composition, gives a character to the whole. 



" This characteristic of an arrangement of colour is generally called its tone ; but it 

 appears that this term is more applicable to individual hues, as it is in music to voices 

 and instruments alone. Yet, to avoid obscurity, I shall continue to use it in the sense 

 in which it is generally applied to coloxiring. 



" From the three primary colours, as will be afterwards shown, arise an infinite 

 variety of hues, tints, and shades, so that the colourist, like the musician, notwith- 

 standing the extreme simplicity of the fundamental principles upon which his art is 

 built, has ample scope for the production of originality and beauty, in the various 

 combinations and arrangements of his materials. 



" The three homogeneous colours, yellow, red, and blue, have been proved by Field, 

 in the most satisfactory manner, to be in numerical proportional power as follows — 

 yellow three, red five, and blue eight. 



" When these three colours are reflected from any opaque body in these proportions, 

 white is produced. They are then in an active state, but each is neutralised by the 

 relative eflFect that the others have upon it. When they are absorbed in the same 

 proportions, they are in a passive state, and black is the result. 



" From the combination of the primary colours the secondary arise, and are Orange, 

 which is composed of yellow and red, in the proportion of three and five ; Purple, 

 which is composed of red and blue, in the proportion of five and eight ; and Green, 

 composed of yellow and blue, in the proportion of three and eight. These are called 

 the accidental or contrasting colours to the primaries, with which they produce har- 

 mony in opposition, in the same manner in which it is eflfected in music by accompani- 

 ment; the orange with the blue, the purple with the yellow, and the green with the 

 red. They are therefore concords in the musical relation of fourths, neutralising each 

 other at sixteen. 



** This neutralising or compensating power, as will be afterwards shown, is the founda- 

 tion of all agreement and harmony amongst colours, and upon it depends also the 

 brilliancy and force of every composition. 



*' From the combination of these secondaries arise the tertiaries, which are also three 

 in number, as follow : Olive from the mixture of the purple and green, Citron from 

 the mixture of the green and orange, and Russet from the mixture of the orange and 

 purple. These three colours, however, like the compounds produced by their admix- 

 ture, may be reckoned under the general denomination of neutral hues, as they are all 

 formed by a mixture of the same ingredients; the three primaries, which always, less 

 or more, neutralise each other. The most neutral of them all being grey, the mean 

 between black and white, as any of the secondaries are between two of the primaries, 

 it may appropriately be termed the seventh colour. These tertiaries, however, 

 stand in the same relation to the secondaries that the secondaries do to the 

 primaries — olive to orange, citron to purple, and russet to green ; and their propor- 

 tion will be found to be in the same accordance, and neutralising each other in- 

 tegrally as 32. 



" Out of the tertiaries arise a scries of other colours, such as brown, marone, slate, 

 &c. in an incalculable gradation, until they arrive at a perfect neutrality in black, as 

 shown in diagram 2. To all of these the same rules of contrast are equally applicable. 

 *' Besides this relation of contrast in opposition, colours have a relation in series, which 

 is their melody. This melody or harmony of succession is found in all the natural 

 phenomena of colour. Each colour on the prismatic spectrum, and In the rainbow, 

 is melodised by the two compounds which it forms with the other two primaries. For 

 instance, the yellow is melodised by the orange on the one side, and the green on 

 the other ; the blue by the green and purple, and the red by the purple and orange. 

 These coincidences can be shown by a diagram where the chromatic scale of the 



* The Laws of Harmonious Colouring, adapted to interior Decorations, Manufac- 

 tures, and other useful Purposes, by D. R. Hay, House-painter, Edinburgh, 3d edition. 

 This is a work of great "merit, and ought to be in the hands of all porsons of taste. 



colourist is accommodated to the diatonic series of the musician, showing that the 

 concords and discords are also singularly coincident. 



** The following diagram exhibits a general harmony of all the colours of any distinc- 

 tive character, simple and compound, except the neutral grey. It vrill be observed 

 that each limb of this diagram forms a series of hues proceeding from one of the pri- 

 maries, and producing a distinct melody or harmony, in succession, of that colour. 

 It will also be seen, that in each of these harmonies, although the primary colour or 

 key-note predominates, the other two primaries enter, in combination, into the ar- 

 rangement. This, however, is more plainly shown when these three melodies are 

 exhibited separately. There is also shown, upon this diagram, the progress from 

 light to darkness, or from white to black ; as also in its nine central divisions, the 

 harmony in succession, and contrast of the primary and secondary colours. The 

 arrangement of this diagram, I trust, will likewise show that all the colours, in their 

 greatest intensity, may be brought together without crudity or harshness : 



'* In all general arrangements of colours, which are not necessarily confined to any 

 particular leading colour or (to continue the analogy) key-note, it ought to be kept 

 in view, what Nature has pointed out in the most distinct manner in all her colourin"-, 

 namely, that those cool-toned and neutraUsed colours which are most agreeable to the 

 eye should predominate, and that vivid and intense colours should, upon all occasions, 

 be used with a sparing hand. 



*' White is produced by the reflection of all the colours simultaneously in their 

 relative neutraUsing proportions. Its contrasting colour is black, with which it is 

 co-relative, being the opposite extreme of neutrality. It lies nearest in series to 

 vellow, which may be reckoned its melodising colour. It, however, harmonises in 

 conjunction and opposition with all other colours. Every colour in its series of tints 

 becomes subdued in force proportionally as it approaches towards white. It is the 

 representative of light as black is of darkness ; its effect on the eye is therefore cheer- 

 ful and enlivening. 



" Yellow, of the three primary colours, partakes most of the nature of white, being 

 the lightest of all decided colours, and the brightest on the prismatic spectrum. Its 

 contrasting colour is purple, a compound of the other two primaries; its proportional 

 power to which is as three to thirteen, either in quaUty or intensity. It constitutes, in 

 combination with red, the secondary orange ; and, when compounded with blue, it pro- 

 duces the secondary green. These two colours are therefore its melodising hues. It 

 is the most powerful of the positive colours, and consequently the least agreeable to the 

 eye, when unaccompanied, or when predominating in a pure state. Being the lightest 

 of positive colours, it, next to white, forms the most powerful contrast to black. 

 Yellow, of coTirse, forms a component part of all tho tertiary or neutral hues, either 

 in predominance or subordination. 



" The tertiary, in which it is the ai'cheus or ruling colour, is that called citron, which, 

 being a compound of orange and green, the two secondaries into which yellow enters, 

 has a greater proportion of that colour than either of the other two tertiaries. Citron is 

 of itself a soft and pleasing colour to the eye, and is the lightest of all distinct hues aris- 

 ing out of the treble combination of the primaries. It is very useful as a contrasting 

 colour among low tones of purple and crimson. In tracing yellow still further down 



