Joe's head was beginning to ache a little now, and his chest felt the strain of holding his breath. But he was not going to come up yet. Benny had done a trick of picking up in his mouth a number of metal coins from the bottom of the tank. Joe wished he had practised that trick, but he had not, and he knew it would be risky to attempt it. However, he decided to try and see if he could open his mouth under water.
It was not easy, but he did it. A little water got down his throat, but he found that by pressing the back of his tongue up against his soft palate he could close the opening to the throat and wind-pipe, and, at the same time, open his mouth.
"If I keep on I'll be able to eat under water," thought Joe, "and that's something Ben can't do—or, at least, hasn't done."
Then Joe bethought himself of a little finish to his tank act. He knew he must bring it to a close soon now, for he was about at the limit of his ability to hold his breath.
It might be said that the ability to hold one's breath differs greatly in individuals. It follows that a person of large lung capacity is able to fill himself with a greater amount of oxygen than a person whose lungs are not well developed.
The world's record, it is said, is four minutes and thirty-seven seconds, and is held by a man. A girl, about eighteen years old, has remained under water doing various things, such as picking up objects in her mouth, three and a half minutes. It can be seen that it is not always a man or a boy who has the largest lung capacity. This girl was not remarkable for size, being, in fact, rather frail. But she had under-water endurance down to a science, and it is even said that her last record was four minutes.
Sponge and pearl divers of tropical countries are credited with power to remain under water for long periods—some claim five minutes—but the records give about three minutes as the average, though it is possible that some exceptional individual may equal five minutes. But they have to work hard while under water, and, of course, divers go deeper than the eight feet in Joe's tank.
Opening his mouth under water gave the young performer an idea.
He stretched out his arms in a tired and lazy manner, yawned with wide-open mouth as though sleepy, and then, using the box his tricks came in as a pillow, he stretched out on the sandy bottom of the tank, and pretended to go to sleep.
And this, coming at the end of his little performance, and when he had been under water nearly three minutes, made quite an impression on the crowd. There was some laughter at Joe's comical antics, but there were also murmurs of wonder at his endurance.