Although enthusiastic, Lilienthal was not impatient: he had the priceless gift of judgment, allied to common-sense. So, when he had his glider built, he made no wild nor dangerous tests. He contented himself, in fact, with a leap from a springboard no more than 3 feet high; and this height he increased gradually to 8 feet. By such humble beginnings, and without risking his life, he proved that his glider would sustain his weight in the air; or, to be more precise, that its wings would exercise a lift sufficient to permit him to glide rather than fall to the ground. So now he began more elaborate tests, seeking hills which had gently-sloping sides, so that he might glide down them. But with many the difficulty was this: the winds near the surface, being broken and disturbed, blew fitfully and in gusts, while what Lilienthal needed was a steady, uniform wind. At length he found favourable conditions at some gravel-pits at Südende; and here, on the brink of a pit, he built a shed and housed his gliders. [Illustration: PLATE II.--SANTOS-DUMONT’S FIRST FLIGHTS. Here, actually in the air, and with its pilot clearly visible at the controls, is seen the craft in which--at Bagatelle in 1906--the airman flew a distance of 230 yards.] Now, patient and assiduous, he began to teach himself the art of aerial balance. Raising his wings to his shoulders he would face the wind--which in his first tests he did not care to be blowing at more than ten or fifteen miles an hour. Then, running against the wind to increase the pressure beneath his wings, he would raise his legs and begin to glide, moving forward and at the same time downward. How he appeared when in flight is indicated by Fig. 23. [Illustration: FIG. 23.--Lilienthal gliding.] His first tests were brief, for the reason that his craft would either dip too sharply, or incline its planes steeply and so check its forward speed. In either event the result was the same: the glide came to an end. But Lilienthal’s caution saved him from being injured in an involuntary descent. It must be remembered he was always moving close to the earth; therefore he had only a short distance to fall. To safeguard himself still further he fitted below his machine a shock absorber, which came into contact with the ground first and lessened the force of any impact. But the difficulties of preserving his balance were great, as he had foreseen; for not only did his glider dip down, or rear itself up, but also--under the influence of wind-gusts--threatened to slip sideways. It was Wilbur Wright, lecturing afterwards upon problems of aerial equilibrium, who said crisply: