The Sea Mystery · Chapter
III: Experimental Detection explained
Inspector French, having determined that the crate was likely transported by a motor lorry with a crane, circulates a query and receives a report from Constable David Jenkins about a crane-lorry seen near Neath.
What happens
Inspector French, having determined that the crate was likely transported by a motor lorry with a crane, circulates a query and receives a report from Constable David Jenkins about a crane-lorry seen near Neath. French then consults coastguard Tom Manners about tidal currents to estimate where the crate might have been thrown into the sea, concluding that an ebb tide would have been used to carry it out. He decides to trace the crane-lorry from Swansea.
Themes in this chapter
Murder and Investigation
French systematically tests theories about the crate's transport, using deduction and witness reports to advance the case.
Nature and Environment
The tidal currents and geography of the Burry Inlet are crucial to understanding how the crate could have been disposed of at sea.
Characters to notice
- Inspector French
Leads the investigation, theorizes about the lorry and crane, interviews Tom Manners, and plans to trace the crane-lorry.
- Tom Manners
Coastguard who discusses tidal currents with French, explaining how the crate could have drifted.
- Constable David Jenkins
Reports seeing a crane-lorry with a tarpaulin-covered crate near Neath on the night of August 22nd.
- Sergeant Nield
Brings French the message about the lorry sighting from Neath police.
Key passages
“French did not believe that the body could have come from anywhere near by. Had anyone disappeared or left the neighbourhood under suspicious circumstances, the police would have known about it. The motor lorry was, therefore, the more likely of the three.”
French reasoned that since no local disappearances were reported, the body must have been brought from farther away, making a motor lorry the most plausible transport.
French's logical deduction about the lorry's necessity.
“As French closed his eyes he seemed to see the reverse process being carried out—a crane-lorry arriving on the Loughor bridge, stopping, backing at right angles to the road until its tail was up against the parapet—the road was wide enough to allow of it; the driver getting down, taking a tarpaulin off a crate, swinging the crate up to the pulley of his crane, lowering the jib until the crate swung suspended over the rushing flood beneath, then striking out some type of slip shackle which allowed the crate to fall clear.”
French visualized a crane-lorry backing up to the bridge, using its crane to lift the crate over the parapet and drop it into the river below.
French's imaginative reconstruction of the murder method.
“A little over five miles from the point at which the crate had sunk the estuary”
The location where the crate sank was about five miles from a key point up the estuary.
French's calculation of distance based on tidal speed.