"No," Lady Parkstone explained. "She is Miss Adela Vane; at present she is playing at the Comedy Opera House. It is just possible that you know the name."
Field knew the name very well. He departed presently well satisfied with the progress that he had made. It was getting quite late by the time he had found out where Miss Vane lodged, but he had time to go back to Scotland Yard again. There, a note from the superin
tendent of the Wandsworth Police was awaiting him, asking him to go down as soon as possible. The note was vague but it suggested possibilities.
The Wandsworth authorities had not much to say, but they had one detail. Last night one of the men who was told to watch No. 100 had seen something. The windows were all shuttered from top to bottom, each shutter having a little ventilator in it. Field nodded, for he had noticed this himself.
"Very well, then," the superintendent went on. "So far as we know the house is empty. But is it? If so why should a light have been seen last night, behind the little round ventilator? The light came and went, and in a great flashing, dazzling kind of way for half an hour, and then stopped. It was as if a child was playing with the switch of the electric light."
Field nodded and smiled. He looked exceedingly pleased with himself.
"Guess I understand," he said. "Especially as we are seeking for a military gentleman. We'll go as far as Audley Place at once, and investigate. Only we shall have to call at the Post Office and borrow a clerk out of the telegraph department. Come along."
Field volunteered no explanation, and his puzzled colleague followed him out of the office. The telegraph operator and the others stood opposite the house in Audley Place till the patience of all was pretty well exhausted. Then suddenly the light began to flicker in the upper part of the house.
"Isn't that a message of some kind?" Field asked of the telegraph clerk.
"Right," the other said promptly. "That's a kind of telegraph dash and dot system. Whistle a bar from