phalia, and of the existence of an unsuspected fleet of air-ships. At the same time details were freely published, from which it became obvious, so far advanced over all other types of rivals were these incomparable vessels, that the world, if need be, lay at their mercy.
It was no longer policy to conceal their presence or their movements, for the panic which their mere approach created was a valuable factor in enforcing their demands. Proceeding in full daylight at a leisurely twenty-five miles an hour, therefore, they crossed the North Sea at a comparatively low altitude, saluting on their way the Prinz Ludwig, which conveyed the departing German Ambassador from these shores. Their arrival above Thanet was timed to be simultaneous with the presentation of Berlin’s demands; upon being informed by wireless that this had taken place, they sailed in extended line formation very slowly towards London. At nightfall they rose a few hundred feet higher in the air, and hung motionless. They were quite secure from attack. No guns then in use could be trained on them at an efficient range even if their outlines could have been discerned. As a matter of fact, ingenious chromatic and mechanical devices rendered the Krupp-Parsevals practically invisible even in the dusk. Their engines were absolutely noiseless; and the only outward lights they displayed were Lietke-ray emanations, serviceable enough to the pilots and signal-readers of the other vessels when seen through their sensitised glasses, but non-existent to everyone else.
"Is it true, Otto," inquired the engineer, "that in England they allow one to inspect their forts and barracks at will?"
"Oh yes," admitted Otto, with a ready smile, "it is quite so. The defences of the Thames have been my especial work during the past two years."
