Suddenly he thought he saw his way. “You say it was neap tides on those three dates in August? What rise and fall does that represent?” “’Bout eighteen feet.” “How soon shall we have that again?” “Not for nearly a week we shan’t. Say next Monday.” “I can’t wait for that. What’s the rise to-morrow?” “Twenty-one foot, eleven.” “And what hour is high water?” “Eight o’clock in the morning.” “That’ll have to do. Look, here is a bus labelled ‘Llanelly.’ Let us get aboard.” At the police station they found not only the superintendent, but Chief Constable Lloyd. “Glad to see you together, gentlemen,” French greeted them. “I’ve been going into the matter of tides and currents in the Inlet with Mr. Manners here, and now I want your help in trying an experiment. Manners informs me that about six weeks ago, the time at which the doctors believe our man was murdered, it was high water in the dead period of the night. To-morrow, Thursday, it will be high water at eight A.M. The maximum run out to sea, Manners says, will begin between one and two hours later, say at nine-thirty. Now, gentlemen, I want to load the crate with a weight equal to that of the body and throw it into the estuary from the Loughor bridge at nine-thirty to-morrow morning. Will you help me?” While French had been speaking, the three men had stared uncomprehendingly, but as he reached his peroration something like admiration showed on their faces. “Well, I’m blessed!” the superintendent said, slowly, while Major Lloyd gave the suggestion his instant approval. “Glad you agree, gentlemen,” said French. “Now if we’re to be ready we shall want a few things arranged. First we’ll have to put stones in the crate to equal the weight of the body. Then we’ll want a carpenter to repair the top where Mr. Morgan broke it. He’ll have to make it watertight with pitch or putty or something: I don’t want it to take any water through the cracks. A lorry will also be needed to carry the crate to the bridge and three or four men to lift it over the parapet.” “Very good,” the chief constable answered. “Nield can arrange all that. Advise him, will you, Superintendent? But you’d better see him yourself, Inspector, and make sure he forgets nothing. Anything else?” “Yes, sir. We don’t want to lose the crate. We shall want a rope round it and a boat in attendance.” “You can fix that up, Manners, can’t you?” “Certainly, sir. I’ll see to it.” “Good. I’ll come down to watch the experiment. Shall we say nine-thirty at the bridge?” At nine o’clock next morning two vehicles left the Burry Port police station. The first was a lorry and on it stood the crate, repaired and loaded with the necessary weight of shingle, due allowance having been made for the fact that the wood was now water-logged. Behind followed a car containing French, Nield, and three constables in plain clothes.