Between the floats, and suspended from rods running in a fore-and-aft direction, were a dozen cylindro-conical objects that the Sub recognized as bombs for dropping upon hostile ships and fortifications.
It was clearly evident that all the power of offence was distributed on or between the floats, leaving the rest of the seaplane for elevating, steering, and propulsion purposes. The main planes were comparatively short in distance from tip to tip, but broad in proportion. The fabric was apparently of light, non-flexible metal, curved with the convex side uppermost, while both planes were set at an angle of about sixty degrees to the centre line. There were two propellers, one set slightly below the planes, the shaft being driven by means of a chain connected with the engine. The second propeller, worked on a shaft within and projecting beyond the main shaft, was so arranged that its rotation was in an opposite direction to that of the after one. By this means the after propeller "gripped" the air thrown back by the foremost one, and a considerable increase in speed was claimed to have been obtained.
Extending right aft for a distance of ten feet beyond the vertical rudder was a long hollow pole made of aluminium. Surrounding it was a canvas covering, secured at the end nearest the main planes by a metal band. This device was supposed to be for the purpose of saving life should the seaplane become disabled in mid-air and be unable to volplane down to the surface of the sea. By drawing the metal band forward the canvas would be distended by the wind and thus form a huge parachute. Provided the crew were not thrown clear of the falling craft they would be able to descend with it at very little risk.
An experiment had been tried in Kuriche Haff only a few days previously. A seaplane was hoisted to a height of two thousand feet by a dirigible. The parachute safety band was released, and the craft dropped. It fell erratically for nearly a hundred yards before the parachute became fully distended; then, tilting nose downwards, it continued descending in a series of spirals, its rate being greatly retarded. Striking the surface of the water the seaplane dived till half the length of her floats and a part of her main planes were submerged. Then, like a cork, she leapt clear of the surface and settled naturally on her floats.
Hamerton, of course, was ignorant of this highly-confidential test, but the unusual sight of a pole projecting far in the wake of the seaplanes attracted his attention. At first he came to the conclusion that it was a form of aerial torpedo tube, till it suddenly occurred to him that it might be a form of arresting the attraction of gravity in the event of an accidental downward plunge.
Almost as soon as the seaplanes passed out of sight Lieutenant Schaffer entered the room, accompanied by the two men who acted as jailers.
"You haf seen part of our Zherman air fleet?" he enquired affably.
"Yes," replied Hamerton; then, on the spur of the moment, he added: "I see you have adopted the parachute principle in the event of an accident?"
"Mein Gott!" ejaculated the astonished lieutenant; "how you know that?"
"Saw it with my own eyes," replied the Sub, delighted at the successful guess he had made. "I thought your people would collar the idea from us sooner or later."