Childcraft
THE HOW
AND WHY LIBRARY
VOLUME 12
How Things Work
World Book, Inc.
a Scott Fetzer company
Chicago London Sydney Toronto
Childcraft—The How and Why Library
(Reg. U.S. Pat. and T.M. Oft. —Marca Registrada)
© 1994 World Book, Inc. All rights reserved. This volume may not be
reproduced in whole or in part in any form without prior written
permission from the publisher.
