Mr. Merrill laughed and replied, “Suppose you look out of the window.”

So they left their cozy table, where nothing but empty dishes told the story of their delightful lunch party, and wandered over to the window where Mary Jane had looked down at the street not much over an hour before. But what a difference! With a sudden, unexpected shift of wind that only the Chicago weather man knows how to bring about, the stiff, cold northeaster that had brought the cold rain of the morning had been sent off and in its place a warm breeze from the south blew softly across the city, bringing with it sunshine and warmth and pleasantness for all.

“Why—” exclaimed Mary Jane, much puzzled, “where’s the rain?”

“Did you want it back?” laughed Mrs. Merrill, and then she explained to the girls something about the effect the big lake might have on weather and told them that one of the queer things about Chicago was its sudden changes to good, or sometimes bad, weather.

“So I was wondering,” said Mr. Merrill, “if you folks wouldn’t like an hour of fresh air and then, if you’re not through shopping we can come back to the stores.”

The girls hadn’t an idea what he might want to do, but they were pretty sure it would be fun. So they agreed that an hour out of doors was just what they most wanted and they went down to get wraps from the check room. They left the umbrellas till later, put on their wraps and left the store.

“Now then,” said Mr. Merrill, “see that big bus down there—we’re going for a ride on the top.”

“What’s a bus?” asked Mary Jane, who had never heard the word before. But before her father could answer they were pushed into the crowd at the crossing, hurried across and the next second Mr. Merrill had hailed a great, lumbering, top-heavy automobile and was helping the girls to step aboard.

The “bus” proved to be a large-sized passenger automobile, with a deck on top for passengers who wished to ride in the open air. Mary Jane and Alice were thrilled with the fun of getting on it. It seemed exactly like going aboard a house-boat on wheels. They stepped into a little hallway and then—and this wasn’t so easy because the bus immediately began to move—they climbed up a curving flight of stairs and walked down an aisle—an awfully wiggly aisle it was too!—to seats on the very front row.

Then, before they had had a chance to look around or feel at home, the conductor, who stood at the back, shouted, “Low bridge!” and everybody ducked their heads while the great bus went under the elevated railroad. Mary Jane felt, truly, as though she must be a person in a story book—Arabian Nights or something marvelous—because surely the things that were happening to her weren’t really happening.