Mr. Strapp, who now sat in their midst, was one of the latter, and a loyal, helpful, companion he had become. Frank had saved the unsophisticated Westerner, fresh from ranch life, from being swindled out of a large sum of money. The ex-ranchman had appreciated this and the good qualities of the three chums, and had become their partner, to the benefit of all.

Ben Jolly, a musician of no mean ability, was another who had come into their lives. Then there were several lads whom Frank had found poor, in trouble, and needing a friend badly. He had given them a helping hand.

In the last preceding book of the series, named, “The Motion Picture Chums’ Outdoor Exhibition; Or, The Film That Solved a Mystery,” the ups and downs of a new venture, the Airdrome, at Riverside Grove, located on the Palisades of the Hudson River, have been recited.

Each of the group was now filling some efficient part in the operations of the Amusement Company organized by Mr. Strapp and the motion picture chums to bring system and success to the chain of photo playhouses they conducted.

An old comrade of Ben Jolly, a professional ventriloquist named Hal Vincent, had managed the Wonderland No. 2 at Seaside Park during the season. At Fairlands a capable young fellow was in the harness, and another deserving lad was operating the Model, a small affair at Belleview, up the Hudson. Dave Sawyer, whom Frank had rescued from the clutches of a cruel taskmaster, named Slavin, had assisted Frank and his partners in making a success of the famous Airdrome, and was now located at Riverside Grove.

Now, at the beginning of the autumn season, the little group had taken up their headquarters at the principal playhouse of the chain. The Empire was the most profitable institution of the group. It was a model, up-to-date, and well patronized the year around. It was like getting back home to once more enjoy its coziness. The motion picture chums had plenty to do with so many ventures on their hands, but “the Tip Top” was the constant ambition of the partners.

Frank was always on the lookout for something new to keep them abreast of the times. As has been seen, he had made an attractive discovery that day. Now its progress was signalized by the extraordinary appearance of Professor Achilles Barrington.

The odd intruder upon the little group seemed now at ease through the generous reception he had received. He set his glasses straight and brushed his hat with his coat sleeve. Then he tapped his head sharply with his knuckles, as if punishing truant ideas that had led him into a blunder, and summoning up new ones.

“Embarrassed—decidedly so,” he observed. “Deep in thought—and all that. Scarcely respectable—bolting in on you this way. Made a bad impression, I fear.”

“Not at all, sir,” responded Mr. Strapp, indulgently. “Our friend, Frank Durham, has paved the way for a genuine welcome. Let me introduce myself—Strapp is my name, and I never say what I don’t mean. I am very glad to meet a person of your education, Professor Barrington. This is Randolph Powell, and this Pepperill Smith.”