PREFACE. THE need of a book of reference giving brief descrip- tions of the various chemicals and other substances which are employed in the paint, colour and varnish trades has been expressed to me by many correspon- dents. In the following pages I have endeavoured to satisfy that need with, I hope, some small measure of success. As regards the methods of manufacture pf pigments like white lead, vermilion, chrome yellow, Prussian blue, etc., I have only briefly referred to them, and for fuller details I would refer readers to my Manual of Painters Colours, Oils and Varnishes, in which they will find them fully described. In my book on Soaps will be found an extended account of the chemistry of oils, and a full account of the methods of extraction, and to this book reference may usefully be made. Although the coal tar colours have come to the front of late years for the preparation of lake pigments, only a brief reference to them has been made their number is now so great that it was...