Jim talks about the early transatlantic cables, and why some of them didn't work.
We see Jagadish Chandra Bose developing early point-contact semiconductors (because the iron filings of coherers tended to rust in the humid climate of Calcutta!)
There is a video of Oliver Lodge making a speech. There is a flip card video of William Crookes (one of the inventors of the cathode ray tube and the originator of the Crooke's cross).
We see actual coherers.
There is simply too much in this video for me to adequately summarize here. Watch the series. Watch it in chunks if you must. But watch it. It is really great.
Thanks Ashish. And thanks to Jim Al-Khalili.