Davis sighed.

"And it would be so perfect if we could be the ones to find out how to beat them," he said dolefully. "That would satisfy your father, and we'd have nothing else to worry about."

Nita looked up into his solemn face, and, in spite of herself, laughed.

"You're worrying too much," she announced. "We're going to take a vacation and go into the music room and I'm going to play soft music that will take your mind off your troubles."

She led him into the tiny music room of the bungalow, and sat down at the small grand piano there.

"You can turn over the music for me," she said gravely as she made room for him on the seat before the keyboard.

There was no music on the rack of the piano, but neither of them thought of that. Davis set down the test tube he had brought with him and prepared to listen. Nita quite forgot to play any recognizable melody, too. Davis thoughtlessly took possession of her left hand, so she idly struck chords with her right, while the two of them talked foolishnesses that were very delightful. They spoke in low tones, and their voices were soft. They were having an amazingly pleasant time.

They heard footsteps on the porch, and self-consciously drew apart. Gerrod and Evelyn were coming indoors to go back into the laboratory to work on wearily in hopes of stumbling on something that might have an effect upon the ever-encroaching Silver Menace. Davis hastily picked up the test tube full of animalcules. As he took it in his hands, however, he uttered an exclamation of astonishment. The contents were no longer silvery! The tube was full of water with a faintly yellowish tinge. Davis' jaw dropped.

"People!" he called hastily. "Come here! Something has happened!"

Gerrod and Evelyn appeared in the doorway.