Henry Ernest Dudeney/Modern Puzzles/140 - The Four-Colour Map Theorem/Mistake

Source Work

 * Geometrical Problems
 * Various Geometrical Puzzles
 * $140$ -- The Four-Colour Map Theorem
 * $140$ -- The Four-Colour Map Theorem


 * Combinatorial & Topological Problems
 * Map Coloring Puzzles
 * $442$. The Four-Color Map Theorem
 * $442$. The Four-Color Map Theorem

Correction
's analysis of this problem does not constitute a proof.

explains it in his $1968$ repackaging as follows: