'Then that was what happened on the Hello Mars IV. That is what happened down in the park today.'
Gilmer nodded, slowly, sadly.
'It wasn't malicious,' he said. 'I am sure of that. Fur-Ball didn't want to hurt anything. He was just lonesome and a little frightened. He was trying to contact some intelligence. Trying to talk with something. He was asleep or at least physiologically dormant when I took him from the ship. Probably he fell into his sleep just in time to save Cooper from the full effects of the ultrasonics. Maybe he would sleep a lot. Good way to conserve energy.
'He woke up sometime yesterday, but it seemed to take some time for him to get fully awake. I detected slight vibrations from him all day yesterday. This morning the vibrations became stronger. I had put several different assortments of food in the cage, hoping he would choose one or more to eat, give me some clue to his diet. But he didn't do any eating, although he moved around a little bit. Pretty slow, although I imagine it was fast for him. The vibrations kept getting stronger. That was when the real hell broke out in the zoo. He seems to be dozing off again now and things have quieted down.'
Gilmer picked up a box-like instrument to which was attached a set of headphones.
'Borrowed these from Appleman down in the sound laboratory,' he said. 'The vibrations had me stumped at first. Couldn't determine their nature. Then I hit on sound. These things are a toy of Appleman's. Only half-developed yet. They let you 'hear' ultrasonics. Not actual hearing, of course, but an impression of tonal quality, a sort of psychological study of ultrasonics, translation of ultrasonics into what they would be like if you could hear them.'
He handed the head-set to Woods and carried the box to the glass cage. He set it on the cage and moved it slowly back and forth, trying to intercept the ultrasonics emanating from the little Martian animal.
Woods slipped on the phones, sat waiting breathlessly.
He had expected to hear a high, thin sound, but no sound came. Instead a dreadful sense of loneliness crept over him, a sense of bafflement, lack of understanding, frustration. Steadily the feeling mounted in his brain, a voiceless wail of terrible loneliness and misery — a heart-wrenching cry of home-sickness.
He knew he was listening to the wailing of the little Martian animal, was 'hearing' its cries, like the whimperings of a lost puppy on a storm-swept street.