From what has been said it is now possible to conceive how things stood when the brothers, Wilbur and Orville Wright, first attacked the problem of flying in the air. Men had flown, or rather had glided through the air, without engines to support and drive them. Machines had flown, without men to control and guide them. If the two achievements could be combined in one, the problem was solved; but the combination, besides bringing together both sets of difficulties and dangers, added new dangers and difficulties, greater than either. Plainly, there were two ways, and only two, of going about the business. Professor Langley held that in order to learn to fly, you must have a flying machine to begin with. Wilbur Wright, whose views on the point never varied from first to last, held that you must have a man to begin with. The brothers were impatient of 'the wasteful extravagance of mounting delicate and costly machinery on wings which no one knew how to manage'. When they began their experiments they had already reached the conclusion that the problem of constructing wings to carry the machine, and the problem of constructing a motor to drive it, presented no serious difficulty; but that the problem of equilibrium had been the real stumbling-block, and that this problem of equilibrium was the problem of flight itself. 'It seemed to us', says Wilbur Wright, 'that the main reason why the problem had remained so long unsolved was that no one had been able to obtain any adequate practice. We figured that Lilienthal in five years of time had spent only about five hours in actual gliding through the air. The wonder was not that he had done so little, but that he had accomplished so much. It would not be considered at all safe for a bicycle rider to attempt to ride through a crowded city street after only five hours' practice, spread out in bits of ten seconds each over a period of five years; yet Lilienthal with this brief practice was remarkably successful in meeting the fluctuations and eddies of wind gusts. We thought that if some method could be found by which it would be possible to practise by the hour instead of by the second there would be hope of advancing the solution of a very difficult problem.'