He was himself rather out of his depth among the unfamiliar figures and formulæ given on the subject. The problem was, How long would it take 579 pounds of water to run through seven one-sixth-inch holes? This, he found, depended on the head, which he could only guess at approximately one foot. He worked for a considerable time and at last came to the conclusion that it would take slightly over an hour. But that his calculations were correct he would not like to have sworn.
At all events, these results were extremely promising and gave him at least a tentative working theory.
But if the crate had floated from the coast to where it was found, the question immediately arose: At what point had it been thrown in?
Here was a question which could only be answered with the help of local knowledge. French thought that a discussion with the coastguard might suggest ideas. Accordingly, he left the hotel and turned towards the harbour with the intention of looking up Manners.
Chapter Three: Experimental Detection
Tom Manners was hoeing in his little garden when French hailed him. He was not a native, but the course of a long career had led him from Shoreditch, via the Royal Navy, to Burry Port. In person he was small, stout, and elderly, but his movements were still alert and his eyes shone with intelligence.
“I want to have another chat with you about this affair,” said French, who had already heard the other’s statement. “Just walk down to the end of the pier with me while we talk.”
They strolled down past the stumpy lighthouse to where they could get a view of the Inlet.
Again it was a perfect afternoon. The sun, pouring down through a slight haze, put as much warmth as was possible into the somewhat drab colours of the landscape, the steel of the water, the varying browns of the mud and sand, the dingy greys and slate of the town, the greens of the grass and trees on the hills beyond. Some four miles away to the right was the long line of Llanelly, with its chimneys sticking up irregularly like the teeth of a rather badly damaged comb. Fifty-three chimneys, French counted, and he was sure he had not seen anything like all the town contained. Beyond Llanelly the coastline showed as a blur in the haze, but opposite, across the Inlet, lay the great yellow stretch of the Llanrhidian Sands, rising through grey-green dunes to the high ground of the Gower Peninsula.
“Let us sit down,” French suggested when he had assimilated the view. “I have come to the conclusion that the crate must have been thrown into the sea at some point along the shore and floated out to where it was found. It would float, I estimate, for about an hour, when enough water would have got in to sink it. Now what I want to know is, Where along the coast might the crate have been thrown in, so as to reach the place at which it was found in an hour?”