The main idea of this 1920s advertisement is that the Columbia Grafonola phonograph
O can be enjoyed by both men and women.
O can be used outside.
O is portable
will improve leisure time.

✔️will improve leisure time.

Explanation:

The main idea of this 1920s advertisement is that the Columbia Grafonola phonograph "will improve leisure time".

The advert gives insight to the benefits the customer will derive from getting a Columbia Grafonola. From the excerpt, we discover that the Grafonola will bring lots of fun, ease of operation and unmuffled sound/tone. Also, it's reveal from the excerpt that the Grafonola is strong and long-lasting. This makes individuals using it for leisure to enjoy it for long.

The Columbia Grafonola is known to be made by the Columbia Graphophone Company in the 20th century. Generally, the Grafonolas are usually driven by a spring motor. The user had to wind up with a crank before playing. But the Columbia Grafonola seems a bit different from others as stated in the excerpt.

jesse stuart was a teacher in rural kentucky.

-seth