H G Wells' "In the Abyss" (short story, hard sf, free): Exploring the bottom of the ocean

An early description of a submarine for exploring the sea surface 5 miles below the water surface. I've'nt read Jules Verne's "20000 Leagues under the Sea"; so no idea if there is any similarity.

Story summary.

Lt Elstead of British navy will be going down in a spherical cabin made of heavy steel that's mostly air & would naturally float. Cabin is padded inside, because passenger is likely to be thrown around in the device that lacks any controls its human occupant exercise. The cabin has two windows of thick glass.

It's tied with a 5 mile rope of some kind of a floatable material to a massive deadweight of lead. At the interface of dead weight & rope is a "clockwork", an automatic mechanism that steers the human cabin up & down as follows:

1. After the deadweight reaches the sea bottom, clockwork triggers the winding of a winch that pulls the rope down, with it bringing the human floating cabin to sea bottom. I don't recall how the deadweight determines that it has reached the bottom; may be a timer.
2. 30 minutes after bringing the cabin down, the clockwork automatically activates a knife that cuts the rope that connects it to cabin; so cabin rises to surface by its buoyancy where it will be retrieved by a waiting ship. Ship is also used for initial lowering of the contraption into the sea. (Why not rewind the winch & let buoyancy raise the cabin? Saving the rope?)

Of course, things don't go as planned. Our explorer meets the intelligent denizens of sea bottom & ends up visiting their city.

See also.

1. H G Wells' "The Land Ironclads" (download): Another hard sf story by author, now describing an early version of a battle tank.

Fact sheet.

First published: Pearson's Magazine, August 1896.
Download full text from Project Gutenberg of Australia.
Download full text as part of the scans of Amazing Stories, September 1926 (about 80GB, with this as the sole complete story!)
Download audio as part of this collection from Internet Archive.
Rating: B.
Related: Stories of H G Wells.