Colston was silent for a few moments, and then he looked up and said—
"There is not the slightest reason why we should not take a shot at Kronstadt, if only to give the Russians a foretaste of favours to come. Still, I won't fire the first shot on any account, simply because that honour belongs to you. I'll fire the second with pleasure."
"Very good," replied Arnold. "We'll have two shots apiece, one each as we approach the fortress, and one each as we leave it. Now come and take a preparatory lesson in the new gunnery."
They went down into the chief saloon, and there Arnold showed Colston a model of the new weapon with which the Ariel was armed, and thoroughly explained the working of it. After this they went to the wheel-house, where Arnold inclined the planes at a sharper angle, and sent the Ariel flying up into the sky, until the barometer showed an elevation of three thousand feet.
Then he signalled to the engine-room, the fan-wheels rose from the deck, as if by their own volition, and, as soon as they reached their places, began to spin round faster and faster, until Colston could again hear the high-pitched singing sound that he had heard as the Ariel rose from Drumcraig Island.
At the same time the speed of the vessel rapidly decreased; the side propellers ceased working, and the stern-screw revolved more and more slowly, until the speed came down to about thirty miles an hour.
By this time the great fortress of Kronstadt could be distinctly seen lying upon its island, like some huge watch-dog crouched at the entrance to his master's house, guarding the way to St. Petersburg.
"Now," said Arnold, "we can go outside without any fear of being blown off into space."
They went out and walked forward to the bow. Arrived there they found two of the men, each with a curious-looking shell in his arms. The projectiles were about two feet long and six inches in diameter, and were, as Arnold told Colston, constructed of papier-maché. There were three blades projecting from the outside, and running spirally from the point to the butt. These fitted into grooves in the inside of the cannon, which were really huge air-guns twenty feet long, including the air-chamber at the breech.
The projectiles were placed in position, the breeches of the guns closed, and a minute later the air-chambers were filled with air at a pressure of two hundred atmospheres, pumped from the forward engines through pipes leading up to the guns for the purpose.