"And now to see how it works in practice!" cried Tom one day. "Are you with me for a long flight, Ned?" "I sure am!" The next evening the Mars, with a larger crew than before, and with Tom, Ned, Mr. Damon and Lieutenant Marbury aboard, set sail. "But why start at night?" asked Ned. "You'll see in the morning," Tom answered. The Mars flew slowly all night, life aboard her, at about the level of the clouds, going on almost as naturally as though the occupants of the cabins were on the earth. Excellent meals were served. "But when are you going to try the guns?" asked Ned, as he got ready to turn in. "Tell you in the morning," replied Tom, with a smile. And, in the morning, when Ned looked down through the plate glass in the cabin floor, he uttered a cry. "Why, Tom! We're over the ocean!" he cried. "I rather thought we'd be," was the calm reply. "I told George to head straight for the Atlantic. Now we'll have a test with service charges and projectiles!" CHAPTER XVIII IN A STORM Surprise, for the moment, held Mr. Damon, Ned and Lieutenant Marbury speechless. They looked from the heaving waters of the ocean below them to the young pilot of the Mars. He smiled at their astonishment. "What--what does it mean, Tom?" asked Ned. "You never said you were going to take a trip as far as this." "That's right," chimed in Mr. Damon. "Bless my nightcap! If I had known I was going to be brought so far away from home I'd never have come." "You're not so very far from Waterford," put in Tom. "We didn't make any kind of speed coming from Shopton, and we could be back again inside of four hours if we had to." "Then you didn't travel fast during the night?" asked the government man. "No, we just drifted along," Tom answered. "I gave orders to run the machinery slowly, as I wanted to get it in good shape for the other tests that will come soon. But I told George, whom I left in charge when I turned in, to head for New York. I wanted to get out over the ocean to try the guns with the new recoil arrangement." "Well, we're over the ocean all right," spoke Ned, as he looked down at the heaving waters. "It isn't the first time," replied Tom cheerfully. "Koku, you may serve breakfast now," for the giant had been taken along as a sort of cook and waiter. Koku manifested no surprise or alarm when he found the airship floating over the sea. Whatever Tom did was right to him. He had great confidence in his master. "No, it isn't the first time we've taken a water flight," spoke Ned. "I was only surprised at the suddenness of it, that's all." "It's my first experience so far out above the water," observed Lieutenant Marbury, "though of course I've sailed on many seas. Why, we're out of sight of land." "About ten miles out, yes," admitted Tom. "Far enough to make it safe to test the guns with real projectiles. That is what I want to do." "And we've been running all night?" asked Mr. Damon.