I'm sorry I don't recognise that passage, though I thought I'd read the complete works of HG Wells.
Please look at how long ago Wells might have written that and how the English of those days differed from today's.
"He it was who bought… " would work today.
"It was he who bought… " would work today.
"… he it was (anything)…" might have worked 100 years ago; not today."
Today, "… diving dress…" is archaic enough to negate any meaning that grammar might have given it.
"… second-hand …" makes it all the more necessary to use the same adjectival hyphen with "… compressed-air…"
With or without the hyphen, nothing like "… apparatus instead of pumping…" could ever work.
Wells had a brilliant imagination and told his stories better than most but like, for instance, Dickens, that doesn't mean he paid much attention to grammar.