Werner remarks, " I could not here enter into an adoption of the seven colours into which the solar ray is divided.by the prism, as principal colours, nor into the distinction of the colours accordingly as they are either simple or compound ; nor could I omit white and black, the former being considered as a combination of all colours, and the latter as the mere privation of light or colour; for these are distinctions that pertain to the theory of colours among natural philosophers, and can not be well applied in common life, in which black is ranked among the colours as well as white and yellow ; and green, which is mixed, considered as a principal colour, as well as red, which is simple.
" In the adoption of the principal colours enumerated above, I am countenanced by Dr. Schceffer, who has ex hibited them, with the exception of the grey, in his sketch of a general association of colour, Regensburg, 1769. I am, however, justified in adding the grey co lour, by observing, that it occurs very frequently in the mineral kingdom ; that the attempt to bring it under any one of the other colours would be attended with many difficulties, and that, if we have respect to denominations, it is considered in common life as actually differing from the others." Werner's External Characters, p 38, 39.
Each of the principal colours contains one which is considered pure or unmixed with any other, and which is called the characteristic colour: thus, snow-white is the enaracteristic colour of white ; ash•grey, of grey ; vel vet-black, of black ; Berlin-blue, of blue; emerald green, of green ; lemon-yellow, of yellow ; carminc-red, of red; and chesnut-brown, of brown.
Werner having thus established eight characteristic colours, lie next defined and arranged the most striking subordinate varieties.
The definitions were obtained principally by occular examination, which enables us speedily to detect the different colours of which the varieties are composed. In detailing the results of this kind of ocular analysis, if we may use the expression, the predominant compo nent parts are mentioned first, and the others in the order of their quantity. Thus apple-green is found to be a compound colour, and we discover, by comparing it with emerald-green, that it is principally composed of that colour and another, which is greyish-white : we therefore define apple-green to be a colour composed of emerald-green and a small portion of greyish.white. The method he followed in arranging the varieties is simple and elegant. He placed together all those va
rieties which contained the same principal colours in a preponderating quantity, and he arranged them in such a manner, that the transition of the one variety into the other, and of the principal colour into the neigh bouring ones, was preserved. To illustrate this by an example: Suppose we have a variety of colour which we wish to teler to its characteristic colour, and also to the variety under which it should be arranged. We first compare it with the principal colours, to discover to which of them it belongs, which in this instance we find to be green. The next step is to discover to which of the varieties of green in the system it can be referred. If, on comparing it with emerald-green, it appears to the eye to be mixed with another colour, we must, by com parison, endeavour to discover what this colour is; if it prove to be greyish-white, we immediately refer the vari ety to apple-green ; if, in place of greyish-white, it is intermixed with lemon-yellow, we must consider it grass-green ; but if it contains neither greyish-white nor lemon-yellow, but a considerable portion of black, it forms blackish-green. Thus, by mere ocular inspection, any person accustomed to discriminate colours correctly, can ascertain and analyse the different varieties of colour that occur in the mineral kingdom.
The transition of the principal colours and their varie ties into each other, he represents by placing the charac teristic colours in the middle of a series of which all the members are connected together by transition, and whose extreme links connect them with the preceding and fol lowing principal colours. Thus, emerald green is placed in the middle of a series, the members of which pass, on the one hand, by increase of the proportion of blue into the next colour-suite, the blue; on the other hand, by the increase of yellow into yellow, siskin-green forming the connecting link with yellow, and verdigris green with blue.
Names of the Colours.
The names of the colours arc derived, 1st, From certain bodies in which they most commonly occur, as milk-white, siskin-green, lit er-bruwn ; 2d, From me tallic substances, as silver-white, iron-black, and gold yellow ; 3d, Frum names used by painters, as indigo blue, teriugrts green, and azure-blue ; 4;11 From that colour in the composition which is next in quantity to the principal colour, as bluish-grey, yellowish-brown, &c.; and, 5th, From the names of persons, as Isabella yellow, now called cream-yellow.