Ferreting around this wonderful tinterweb, I stumbled across the article linked below. If it has been posted before I apologise in advance. Pressure Lamps International, History page
It is a good read even if some of the information is a little bit unreliable by todays standards. Researching old companies is far easier these days so kudo's to a well written article considering the era it was written in.
It's a shame it doesn't mention Goldsworthy Gurney and the Bude Light of about 1839. That was reckoned good enough to light the Houses of Parliament for 50 years from 1853. Four of the lanterns still stand around London's Leicester Square today but powered by Electricity. The pedestal base of one is even a very small police post.