Internal evidence dates this as 1936. I'm a sucker for this sort of trivia collection. Among the thoroughly useless things I learned were how to identify a British train's type by the arrangement of its headlights, the proper way to use an oar as a life-saving device, that woodpeckers go "Heearfie-arfie-arfa," and that ox-hair was used to wrap steam-pipes. I have never heard of sucking on pebbles to combat seasickness. If this really works I'll have to tell my seasickness-inclined brother. I found it interesting that in the list of countries from which food was imported no food is shown coming from France, Italy, Germany, or Eastern Europe.
Link to the book:
The Hotspur What You Dont Know