When the book was written in 1941, he was a graduate student. His attempts to popularize science were many years in the future. Lorenz's work with chaos and powerful enough computers to enable it were still 20 years in the future. Terms such as "the butterfly effect" did not get introduced for another decade.
It was unlikely that he was unfamiliar with chaos. Doubly so given that the first prediction of what we now call chaos theory is that we won't see the periodic behavior that is a fundamental premise of the story.
It was unlikely that he was unfamiliar with chaos. Doubly so given that the first prediction of what we now call chaos theory is that we won't see the periodic behavior that is a fundamental premise of the story.