In the two first parts the author's statements are arranged numerically, in the style of Bacon's Natural History. This, we are told, was for the convenience of reference; but many passages are thus separately numbered which hardly seem to have required it. The same arrangement is, however, strictly followed in the translation to facilitate a comparison with the original where it may be desired; and here the translator observes, that although he has sometimes permitted himself to make slight alterations, in order to avoid unnecessary repetition, or to make the author's meaning clearer, he feels that an apology may rather be expected from him for having omitted so little. He was scrupulous on this point, having once determined to translate the whole treatise, partly, as before stated, from a wish to deal fairly with a controversial writer, and partly because many passages, not directly bearing on the scientific views, are still characteristic of Goethe. The observations which the translator has ventured to add are inserted in the appendix: these observations are chiefly confined to such of the author's opinions and conclusions as have direct reference to the arts; they seldom interfere with the scientific propositions, even where these have been considered most vulnerable. [1] "Farbenlehre"--in the present translation generally rendered "Theory of Colours." [2] Sixteen years after the appearance of the Farbenlehre, Dr. Johannes Müller devoted a portion of his work, "Zur vergleichenden Physiologie des Gesichtssinnes des Menschen und der Thiere," to the critical examination of Goethe's theory. In his introductory remarks he expresses himself as follows--"For my own part I readily acknowledge that I have been greatly indebted to Goethe's treatise, and can truly say that without having studied it for some years in connexion with the actual phenomena, the present work would hardly have been undertaken. I have no hesitation in confessing more particularly that I have full faith in Goethe's statements, where they are merely descriptive of the phenomena, and where the author does not enter into explanations involving a decision on the great points of controversy." The names of Hegel, Schelling, Seebeck, Steffens, may also be mentioned, and many others might be added, as authorities more or less favourable to the Farbenlehre.