He had an idea that anything accepted by a paper was published immediately, and as he had sent the manuscript in on Friday he expected it to come out on the following Sunday.

He conceived that it would be fine to let that event apprise Ruth of his return.

Then, Sunday afternoon, he would call and see her.
In the meantime he was occupied by another idea, which he prided himself upon as being a particularly sane, careful, and modest idea.

He would write an adventure story for boys and sell it to The Youth's Companion.
He went to the free reading-room and looked through the files of The Youth's Companion.

Serial stories, he found, were usually published in that weekly in five instalments of about three thousand words each.