The enormous expense of his experiments has not prevented Sir Hiram Maxim from repeating them, and he hopes soon to have a much improved machine. Nevertheless his experience and calculations have been of great value to those who would follow in his footsteps, and have proved the possibility of constructing a flying machine which shall fly by virtue of its own motion. Meanwhile in America Professor Langley was experimenting, independently, almost on the same lines. He also was bent on producing a flying machine, but instead of starting to work upon a large apparatus like Maxim, he began by making models, and gradually worked his way up to bigger things. For many months he studied to understand the principle of those ingenious little toys sometimes seen, which, by means of the tension of a twisted india-rubber band, will keep afloat in the air for a few seconds. Next he constructed small models driven by steam, in which he found his great difficulty was in keeping down the weight. For years he persevered in his work without any great success, until in 1896 he produced a model machine which he called an “aerodrome.” It was quite small, weighing with its engine only 25 lbs., and measuring but 14 feet from tip to tip of its aeroplanes. The experiments were made over water, and the necessary momentum was given by dropping it from a platform 20 feet high. On more than one occasion this little flying machine rose with great steadiness in the face of the wind to a height of 100 feet, moving so smoothly that it might have carried a glass of water without spilling a drop; and then, the steam of its engine being exhausted, sank down gracefully upon the water, having flown about half a mile in a minute and a half. This success encouraged Professor Langley next to construct a full-sized flying machine on the same lines; but this on its first voyage plunged headlong into the water and was hopelessly damaged. The United States Government have since granted him a sum of money to continue his experiments. Latest of all the airship inventors, and perhaps so far the most successful, are the brothers Wright. Up to the date of writing this the full details of their work are not yet made public, but it is known that on the 17th of December 1903, their machine, which consists of two large aeroplanes driven forward by an engine of sixteen horse-power, after being started along a short track on level ground, rose into the air and flew for about half a mile.