Transcriber’s Note Italic text is enclosed in _underscores_; subscripts are enclosed in {curly brackets}. Additional notes will be found near the end of this ebook. THE MANUFACTURE OF EARTH COLOURS THE MANUFACTURE OF EARTH COLOURS BY DR. JOSEF BERSCH TRANSLATED FROM THE THIRD GERMAN EDITION (AS REVISED BY PROF. DR. WILHELM BERSCH) BY CHARLES SALTER _WITH THIRTY-ONE ILLUSTRATIONS_ LONDON SCOTT, GREENWOOD & SON 8 BROADWAY, LUDGATE, E.C.4 1921 [_The sole rights of translation in English remain with Scott, Greenwood & Son._] PRINTED IN GREAT BRITAIN BY RICHARD CLAY & SONS, LIMITED, PARIS GARDEN, STAMFORD ST., S.E. 1, AND BUNGAY, SUFFOLK. PREFACE Originally issued as a volume of the series on pigments and colouring matters by the present author’s father, the necessity for a new edition afforded a welcome opportunity of revising “_Earth Colours_.” Although, in the nature of things, little progress has been made in this subject itself, there was a good deal to add in connection with the mechanical appliances for treating the colour earths and manufacturing them into pigments. In other respects, too, the work has been carefully gone through and brought up to date, with new and additional illustrations. The author desires to express his thanks to the various firms who have afforded him assistance in his task by furnishing illustrations and descriptions of new machinery, together with other information. It is hoped that this third edition will meet the approval of those interested in the subject; and the author will be glad to receive supplementary information to render the work more complete in the event of a future edition being found advisable. PROF. DR. WILHELM BERSCH. 1918. CONTENTS CHAPTER I PAGE INTRODUCTORY 1 CHAPTER II THE RAW MATERIALS FOR EARTH COLOURS 8 (A) White Raw Materials and Pigmentary Earths 11 Limestone (Calcite, Limestone, Chalk) 11 Gypsum (Alabaster) 18 Barytes, or Heavy Spar 19 Talc, Soapstone, Steatite 20 Clay 21