The successful airship was of moderate proportions as compared with that of Count Zeppelin. The cigar-shaped bag was 112 feet long and 20 feet in diameter, holding 715 cubic yards of gas. M. Dumont showed originality in furnishing it with a smaller balloon inside, which could be pumped full of air so as to counteract any leakage in the external bag and keep it taut. The motor, on which everything depended, was a four-cylinder petrol-driven engine, furnished with “water-jackets” to prevent over-heating. The motor turned a large screw--made of silk and stretched over light frames--200 times a minute, giving a driving force of 175 lbs. Behind, a rudder directed the airship, and in front hung down a long rope suspended by one end that could be drawn towards the centre of the frame to alter the trim of the ship. The aeronaut stood in a large wicker basket flanked on either side by bags of sand ballast. The fact that the motor, once stopped, could only be restarted by coming to earth again added an element of great uncertainty to all his trips; and on one occasion the mis-firing of one of the cylinders almost brought about a collision with the Eiffel Tower. From Paris M. Dumont went to Monaco at the invitation of the prince of that principality, and cruised about over the bay in his balloon. His fresh scheme was to cross to Corsica, but it was brought to an abrupt conclusion by a leakage of gas, which precipitated balloon and balloonist into the sea. Dumont was rescued, and at once set about new projects, including a visit to the Crystal Palace, where he would have made a series of ascents this summer (1902) but for damage done to the silk of the gas-bag by its immersion in salt water and the other vicissitudes it had passed through. Dumont’s most important achievement has been, like that of Count Zeppelin, the application of the gasolene motor to aeromobilism. In proportion to its size this form of motor develops a large amount of energy, and its mechanism is comparatively simple--a matter of great moment to the aeronaut. He has also shown that under favourable conditions a balloon may be steered against a head-wind, though not with the certainty that is desirable before air travel can be pronounced an even moderately simple undertaking. The fact that many inventors, such as Dr. Barton, M. Roze, Henri Deutsch, are fitting motors to balloons in the hopes of solving the aërial problem shows that the airship has still a strong hold on the minds of men. But on reviewing the successes of such combinations of lifting and driving power it must be confessed, with all due respect to M. Dumont, that they are somewhat meagre, and do not show any great advance.