This is one of several stories which first appeared in the This Week supplement to a number of North American newspapers.
Old Man Thornton is a lighthouse-keeper on the west African coast. A man and a woman in a sailing dinghy land on his rock during a storm. They accidentally show him that they are carrying a large sum of cash. Once he has seen it, he will have to die in case he reports it, but meanwhile he has to keep the light burning until the storm is over. He is watched to ensure he does not send any signals using the light. Will he be able to send one none the less?
In the British version, published a month later, the name of the main character has been altered from "Old Man Thornton" to "Pop Gallop" and the ending has been slightly re-written.
Published in This Week Magazine, 7 October 1956.
Reprinted as "Message to the Mainland" with illustrations by Zelinski in John Bull, 3 November 1956, p. 11 - 13.
Included in comic strip form as "The Mystery of the Lighthouse" in "The three riddles", Super Detective Library No 106, 1957. (No artist credit printed.)
Included in the collection Crime and Detection, ed. John Higgins.