The invention being now so far advanced as to be entitled to a place among the arts, it was thought that it should have its distinctive appellation, and by the advice of the same illustrious body, that of Metallochromy was adopted. Since that period I have made such improvements in my method that the first results, though they appeared satisfactory at the time, make but a sorry figure when compared with those now obtained. One of the great difficulties consisted in the necessity of producing a uniformity of tint on plates of certain dimensions; for, my colours being obtained by the effect of very thin plates applied to the surface of metals, it is easy to conceive how hard it was to preserve such plates of a uniform thickness over the whole of an extensive surface. Great however as the difficulties were, I thought I owed it both to art and to science to do my utmost to surmount them. I thought it due to art, because this would be extended by means of the uniformity of the tints, and to science, because in the tints produced by plates of a particular thickness the experimental philosopher would find the means of investigating with peculiar advantage the nature and properties of colours.
At present I abstain from all detail relative to the method of obtaining the homogeneous tints. The principle of the electro-chemical appearances seems now so fertile in results that its full development requires a particular treatise. It will be a work of considerable labour, and I have already commenced it by collecting and classifying all the materials of this new department of physics in which, besides the other methods of coloration, I intend to explain in detail those connected with the production of uniform tints. In this place it is sufficient to state that these tints are produced by substituting plates for the platina point which forms the coloured rings.
The object of this Memoir is more limited. It is to arrange these homogeneous tints in their natural order, so that they may form a scale or gamut which I shall henceforth designate by the epithet chromatic.
Science never consults its interests so truly as when it aims at some useful object connected with the arts. Such, I would fain hope, will be the direction of these researches. Artists, it is true, being generally unacquainted with physical theories, will find it difficult to follow me in my inquiries. My labour, however will not be altogether useless to them, if, as I intended, I have succeeded in treating certain parts of the subject in a manner likely to bring them within the reach of every understanding.
The formation of the chromatic scales requires considerable time and a hand well practised in work of this description. As they might be generally useful I regret that the difficulty of their construction renders a prompt and wide-spread circulation of them impossible. I have tried and am still trying to have them copied in oil and water colours, but
