The mania for speculation broke loose. Stock soared in three months from 128 to 300, and within a few months more to 500. Amid the resounding cries of jobbers and speculators a multitude of companies, some genuine and some bogus, was hatched. By June 1721 the South Sea stock stood at 1050. Robert Walpole himself had the luck to make a handsome profit on his quiet investments. At every coffeehouse in London men and women were investing their savings in any enterprise that would take their money. There was no limit to the credulity of the public. One promoter floated a company to manufacture an invention known as Puckle's Machine Gun, "which was to discharge round and square cannon-balls and bullets and make a total revolution in the art of war," the round missiles being intended for use against Christians and the square against the Turk. Other promoters invited subscriptions for making salt water fresh, for constructing a wheel of perpetual motion, for importing large jackasses from Spain to improve the breed of English mules, and the boldest of all was the advertisment for "a company for carrying on an undertaking of Great Advantage, but no one to know what it is." This amiable swindler set up shop in Cornhill to receive subscriptions. His office was beseiged by eager investors, and after collecting £2,000 in cash he prudently absconded.

Winston S. Churchill, A History of the English-Speaking Peoples: The Age of Revolution (110-111)