The drawback, in the matter of dirigible balloons, lay in the fact that the huge bag, necessary to keep them aloft, made them the sport of every wind that blew. If the volume of gas could be reduced, then, naturally, the smaller the gas bag, the more practicable the dirigible would become. With the volume of gas reduced _fifty times_, a field opened for power-driven balloons which fairly took Matt’s breath away. And this lifting power of Lafitte’s was under control! This seemed to offer realization of another of Matt’s dreams--of an automobile flying machine, a surface and air craft which could fly along the roads as well as leap aloft and sail through the atmosphere above him.