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viii FOREWORD

with inisturęs, but mixtures often having " structure," " orientation," " thixotropy ” or sonie other qualification. If the rheologist can explain the vagaries of these mixtures and those near-mixtures dear to the colloid chemist, he will no doubt have justified Sir Thomas Graham in calling tlie viscometer a | colloidoscope.”

E. C. BINGHAM.

PREFACE

Some years ago, when holding a Rockefeller Fellowship in the United States, I had the oppor-tunity of visiting a number of industrial laboratories associated with the very diverse industries in which rheological methods are employed. I was much struck with the similarity of methods and of diffi-culties to be found in them, and enjoyed hearing these discussed at the First Congress of the Society of Rheology in Washington (D.C.). On my return to England, and during occasional visits to other countries, I attempted to co-ordinate the information available from different sources, and, as part of my course of lectures on Colloids at the Sir John Cass Technical Institute last spring, I devoted ten lectures to this subject. At the reąuest of some of those who attended, and with the kind approval of the Principal, I have decided to publish these lectures, only slightly modified, in book form.

Any original ideas to be found in this book have been developed in discussion with rheologist friends too numerous to name individually. I should like, however, to thank especially Professor E. C. Bingham for his interest, and for his kindness in adding a Foreword, Dr. Markus Reiner, who has read the manuscript, for his suggestions, Miss V. Coppen, who has helped especially in the writing of the paragraph on the psychological aspects of rheology, and my wife, who has undertaken the task of converting my lecture notes into book form.

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