"In order, then, to render such balloon voyages possible at all, it was necessary, in the first place, to afford the machine its required support, its resistance, and this was accomplished in the following manner: The long cylinder which runs along the whole of the ship is a bar of malleable iron, surrounded by a spiral copper wire which has been coated with an insulating substance. If, now, a voltaic current is made to pass along that wire, the bar becomes a most powerful electro-magnet, which, when free in its movements, like the needle of a compass, adopts a direction from south to north, with a slight easterly deviation, and also a certain inclination. When driven out of its natural direction by another power, the needle will endeavour to resume its original inclination. As, now, the magnet and the vessel are so joined together as virtually to form but one body, the balloon, or rather the ship, is in itself a gigantic compass. The inclination is removed just the same as with the needle of the compass. One has merely to alter the centre of gravity, and this can be done in several ways. Thus, all that remains is the direction in the magnetic meridian. "If, now, the wind blows in the same direction that one wishes to travel, then the apparatus is not worked; that is to say, no current is passed through the wire. Should the wind, however, be unpropitious, then the ship is at once changed into a magnet. For example, suppose the wind to be due west, and the sails to be placed at right angles with the wind, then the vessel will be driven neither east nor northward, but towards a point intermediate; just as a vessel at sea when pushed north by the current of the water, and westward by the wind, does not follow either of these directions exclusively, but an intermediate one. It is not difficult, therefore, to perceive that the aëronaut, by the proper joint working of his sails and of the electro-magnetic apparatus, is enabled to turn his ship into any direction he chooses. Nor is that all. The apparatus also serves as a helm or rudder; for as soon as I press this knob the current is at once reversed; the north pole becomes the south pole, and vice versâ. It stands to reason that the vessel must turn under the circumstances, and, of course, according to pleasure; for at any moment the helmsman may interrupt the current, whereby the ship ceases to be a magnet. "Now, as indeed at sea, the case may be that the wind is too strong, and the power of the magnet insufficient to properly govern the air-ship. In that case we have recourse to those energeiathecs of which I spoke yesterday; these tend to set in circular motion the four-winged screws which you see here and there peeping out of the sides, and this is always done as near as possible at right angles with the direction in which the vessel has a tendency to deviate.