The editors feel bound, in justice to Mr. Baker, to say that he feared that our readers would think that we had erred in choosing the accounts of inventions which have progressed so immeasurably since his articles were written. The editors, on the other hand, desired to do precisely the thing that Mr. Baker feared to have them do. They desire to show what a keen, well-trained observer saw in these inventions, which now play so vital a part in our lives, when the inventions were new. Further, it is our desire that the name of Professor Langley, of Washington, D. C., should be properly honored in connection with the advance of the science of aviation. Indeed, but recently, when tried by an experienced aviator, his machine flew successfully. Professor Langley died as an indirect result of his untiring, unselfish, and heroic efforts in this then new cause. In spite of ridicule and contempt, in spite of lack of support, he went courageously ahead; and it is right that the boys of Wisconsin should know that a young man of their state has given due credit in his book to this heroic soul. [Illustration: RAY STANNARD BAKER] THROUGH THE AIR From "THE BOYS' BOOK OF INVENTIONS," Chapter IX, by Ray Stannard Baker. Copyright, 1899, by Doubleday, Page & Co. Probably no American inventor of flying machines is better known or has been more successful in his experiments than Professor S. P. Langley, the distinguished secretary of the Smithsonian Institution at Washington. Professor Langley has built a machine with wings, driven by a steam-engine, and wholly without gas or other lifting power beyond its own internal energy. And this machine, to which has been given the name Aerodrome (air-runner), actually flies for considerable distances. So successful were Professor Langley's early tests, that the United States Government recently made a considerable appropriation to enable him to carry forward his experiments in the hope of finally securing a practical flying machine. His work is, therefore, the most significant and important of any now before the public (1899). The invention of the aerodrome was the result of long years of persevering and exacting labor, with so many disappointments and set-backs that one cannot help admiring the astonishing patience which kept hope alive to the end. Early in his experiments, Professor Langley had proved positively, by mathematical calculations, that a machine could be made to fly, provided its structure were light enough and the actuating power great enough. Therefore, he was not in pursuit of a mere will-o'-the-wisp. It was a mechanical difficulty which he had to surmount, and he surmounted it.