A company "for carrying on an undertaking of great advantage but no one to know what it is."From a company prospectus (reputedly) issued in London at the height of the South Sea Bubble, the iconic examplar of froth and folly in company promotion. FWIW, I have my doubts that there ever was such a prospectus: there are a swarm of Google hits; I haven't combed them all but I haven't seen any one with real sourcing. Maybe the Republicans will at last plug the gap. Cf. Link.Link., Link, etc.