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PREFACE 
During some extended study of the subject he has 
collected a variety of data which have been embodied 
in this volume, and which he trusts may be useful to 
those who have to deal with cargo-handling problems. 
Many thanks are due to friends and others who have 
kindly supplied information and assisted to complete 
the presentation of figures and illustrations. 
BROAD SANCTUARY CHAMBERS, 
WESTMINSTER, August, 1923.