IRE Title Page title page Butterworth & Company Karen Sparck Jones All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, including photocopying and recording, without the written permission of the copyright holder, application for which should be addressed to the Publishers. Such written permission must also be obtained before any part of this publication is stored in a retrieval system of any nature. Information Retrieval Experiment Edited by Karen Sparck Jones For CYRIL CLEVERDON from whom we have all learnt a lot Butterworths London Boston Sydney Wellington Durban Toronto