“Well, obviously it could not have been meant for the son. The son, as far as he knew, was in Bristol. It was mere chance that he was within ear-shot. The ‘Cooee!’ was meant to attract the attention of whoever it was that he had the appointment with. But ‘Cooee’ is a distinctly Australian cry, and one which is used between Australians. There is a strong presumption that the person whom McCarthy expected to meet him at Boscombe Pool was some one who had been in Australia.”
“What of the rat, then?”
Sherlock Holmes took a folded paper from his pocket and flattened it out on the table. “This is a map of the Colony of Victoria,” he said. “I wired to Bristol for it last night.” He put his hand over part of the map. “What do you read?” he asked.
“ARAT,” I read.
“And now?” He raised his hand.
“BALLARAT.”
“Quite so. That was the word the man uttered, and of which his son only caught the last two syllables. He was trying to utter the name of his murderer. So-and-so, of Ballarat.”
“It is wonderful!” I exclaimed.
“It is obvious. And now, you see, I had narrowed the field down considerably. The possession of a gray garment was a third point which, granting the son’s statement to be correct, was a certainty. We have come now out of mere vagueness to the definite conception of an Australian from Ballarat with a gray cloak.”
“Certainly.”