What are some errors made in puzzle books?

geometry/fence

Charles W. Trigg, Mathematical Quickies, Dover, 1985, #93

logic/calibans.will

Hubert Phillips, Caliban's Problem Book: Mathematical, Inferential
  and Cryptographic Puzzles, T. De La Rue & Co Ltd., London, 1933

logic/hundred

Angela Dunn, ed., Mathematical Bafflers, Dover, 1980, p. 112
David Wells, The Penguin Book of Curious and Interesting Puzzles, Penguin,
  1992, #373 & #554

probability/apriori

Dodgson, Charles L. (AKA Lewis Carroll), Pillow-Problems, Macmillan, 1895, #5

physics/juggling.bridge

Paul Sloane, Lateral Thinking Puzzlers
[ Editor: entry added for the juggling answer questioned by Paul
Leyderman; the edition is not given in the posting. ]