Instantly the whistle sounded, the model signaled was released without a moment’s delay. In this way no two models were ever started at the same time, and all confusion was avoided. The whistle was clearly heard in all parts of the hall, and the audience quickly learned to recognize the signals and look to the point from which the start took place. In the distance flights the one flying the model and the measurer alone were allowed to go after the machine. This was done on the run. It is important that any delay be avoided in measuring, since this does not interest the public in the least, and may make the exhibition drag. [Illustration: An interesting experiment in stability] [Illustration: An early model built by Monroe Jacobs. Note the Ailerons.] The only other person allowed on the floor while the flights were in progress was the owner of the model, who must follow it and bring it back. He was allowed to cross the floor, but once he had secured his model, he must carry it quickly to the nearest point at the side, and find his way back to the starting point along the outer lines. It is confusing both to the flyer and the spectators to have a single unnecessary figure on the floor during the flights. The crowd is kept back by members of the club, wearing the club colors. The regular fortnightly model aeroplane meets held in New York are doubtless the most largely-attended and best-organized meets of the kind in the world. The 22nd Regiment armory, a spacious structure admirably suited for indoor aviation, has very courteously been thrown open for the purpose on every other Saturday afternoon. Throughout the season, each of these meets brings together several hundred boys and spectators, and on the average about 100 model aeroplanes. The meet is conducted with intelligence and sympathy by the Y. M. C. A., and is open to all. Of late these exhibitions have become so popular that the crowds actually threaten the convenience of the flyers, and the boys have been required to present credentials on entering, consisting simply of a model aeroplane. There are few more animated spectacles than the model aeroplane tournament. There is a great sunlit floor, measuring 250 by 150 feet, roofed with glass. The aviation fields are reproduced here in miniature, without loss of animation. Along the sides are continuous lines of "camps," corresponding to the hangars where scores of boys are busy tuning up their machines. They have brought tools and a variety of extra materials, planes, propellers, motors, and strips, which are spread about them. In each camp the machines,—and there are no two alike,—are being assembled or repaired. Groups of the boys’ friends and admirers are gathered about each camp, earnestly discussing the merits of a particular model and its chances in the approaching contest. To stroll down the line of camps is in itself a liberal education in aeronautics.