While it is necessary to make glides against the wind, it is not wise to attempt flights when the wind blows harder than 10 miles an hour. While the flight may be successful, the landing may be disastrous. The accomplished glider operator is in line for the aeroplane, and it is safe to say that he will not be long without one. The skilful and practised operator of a glider makes the very best aeroplane pilot. This chapter would not be complete without an adequate reference to the gliders devised by Professor Montgomery of Santa Clara, California. These machines were sent up with ordinary hot-air balloons to various heights, reaching 4,000 feet in some instances, when they were cut loose and allowed to descend in a long glide, guided by their pilots. The time of the descent from the highest altitude was twenty minutes, during which the glider travelled about eight miles. The landing was made accurately upon a designated spot, and so gently that there was no perceptible jar. Two of the pilots turned completely over sideways, the machine righting itself after the somersault and continuing its regular course. Professor Montgomery has made the assertion that he can fasten a bag of sand weighing 150 lbs. in the driver’s seat of his glider, and send it up tied upside down under a balloon, and that after being cut loose, the machine will right itself and come safely to the ground without any steering. Lilienthal in Germany, Pilcher in England, and Chanute in the United States are names eminent in connection with the experiments with gliders which have been productive of discoveries of the greatest importance to the progress of aviation. The illustration of the Chanute glider shows its peculiarities plainly enough to enable any one to comprehend them. The establishment of glider clubs in several parts of the country has created a demand for ready-made machines, so that an enthusiast who does not wish to build his own machine may purchase it ready made. Chapter XIII. BALLOONS. First air vehicle--Principle of Archimedes--Why balloons rise--Inflating gases--Early history--The Montgolfiers--The hot-air balloon--Charles’s hydrogen balloon--Pilatre de Rozier--The first aeronaut--The first balloon voyage--Blanchard and Jeffries--Crossing the English Channel--First English ascensions--Notable voyages--Recent long-distance journeys and high ascensions--Prize balloon races--A fascinating sport--Some impressions, adventures, and hardships--Accident record--Increasing interest in ballooning.