THE PRINCIPLES OF BEAUTY IN COLOURING SYSTEMATISED. _From the Spectator._ In this new analysis of the harmonies of colour, Mr Hay has performed the useful service of tracing to the operation of certain fixed principles the sources of beauty in particular combinations of hues and tints; so that artists may, by the aid of this book, produce, with mathematical certainty, the richest effects, hitherto attainable by genius alone. Mr Hay has reduced this branch of art to a perfect system, and proved that an offence against good taste in respect to combinations of colour is, in effect, a violation of natural laws. VI. In 8vo, 228 Examples of Colours, Hues, Tints, and Shades, price 63s., A NOMENCLATURE OF COLOURS, APPLICABLE TO THE ARTS AND NATURAL SCIENCES. _From the Daily News._ In this work Mr Hay has brought a larger amount of practical knowledge to bear on the subject of colour than any other writer with whom we are acquainted, and in proportion to this practical knowledge is, as might be expected, the excellence of his treatise. There is much in this volume which we would most earnestly recommend to the notice of artists, house decorators, and, indeed, to all whose business or profession requires a knowledge of the management of colour. The work is replete with hints which they might turn to profitable account, and which they will find nowhere else. _From the Athenæum._ We have formerly stated the high opinion we entertain of Mr Hay’s previous exertions for the improvement of decorative art in this country. We have already awarded him the merit of invention and creation of the new and the beautiful in form. In his former treatises he furnished a theory of definite proportions for the creation of the beautiful in form. In the present work he proposes to supply a scale of definite proportions for chromatic beauty. For this purpose he sets out very properly with a precise nomenclature of colour. In this he has constructed a vocabulary for the artist—an alphabet for the artizan. He has gone further—he constructs words for three syllables. From this time, it will be possible to write a letter in Edinburgh about a coloured composition, which shall be read off in London, Paris, St Petersburg, or Pekin, and shall so express its nature that it can be reproduced in perfect identity. This Mr Hay has done, or at least so nearly, as to deserve our thanks on behalf of art, and artists of all grades, even to the decorative artizan—not one of whom, be he house-painter, china pattern-drawer, or calico printer, should be without the simple manual of “words for colours.” VII. In post 8vo, with a Coloured Diagram, Sixth Edition, price 7s. 6d., THE LAWS OF HARMONIOUS COLOURING ADAPTED TO INTERIOR DECORATIONS. _From the Atlas._