By degrees, Exeter became too narrow a stage for her performances, and she came to London on the invitation and at the expense of Sharp, the eminent engraver. She was very illiterate, but wrote numerous letters and pamphlets, and her prophecies, nearly unintelligible as they were, had a large sale. In the course of her Mission, as she called it, promising a speedy approach of the Millennium, she employed a boy, who pretended to see visions, and attempted, instead of writing, to adjust them on the walls of her chapel, "the House of God," a large building which adjoined the Elephant and Castle Inn, at Newington Butts. A schism took place among her followers, one of whom, named Carpenter, took possession of the place, and wrote against her; not denying her Mission, but asserting that she had exceeded it. It may, however, be interesting here to describe what may be termed the _modus operandi_ of the delusion. Great pains were now taken to ascertain the truth of her commission. "From the end of 1792," says Mr. Sharp, who, we have already seen, was the most devout of her believers, "to the end of 1794, her writings were sealed up with great caution, and remained secure till they were conveyed by me to High House, Paddington; and the box which contained them was opened in the beginning of January, 1803. Her writings were examined during seven days, and the result of this long scrutiny was the unanimous decision of twenty-three persons _appointed by divine command_, as well as of thirty-five others that were present, _that her calling was of God_." They came to this conclusion from the fulfilment of the prophecies contained in these writings, and to which she appealed with confidence and triumph. It was a curious circumstance, however, that her handwriting was illegible. Her remark on this occasion was, "This must be, to fulfil the Bible. Every vision that John saw in Heaven must take place on earth; and here is the sealed book, that no one can read!" A protection was provided for all those who subscribed their names as volunteers, for the destruction of Satan's kingdom. To every subscriber a folded paper was delivered, endorsed with his name, and secured with the impression of Joanna's seal in red wax; this powerful talisman consisted of a circle enclosing the two letters J. C., with a star above and below, and the following words, "The sealed of the Lord, the Elect, Precious, Man's Redemption, to inherit the tree of life, to be made heirs of God and joint-heirs of Jesus Christ." The whole was authenticated by the signature of the prophetess in her illegible characters, and the person thus provided was said to be _sealed_. Conformably, however, to the 7th chapter of the Revelation, the number of those highly protected persons was not to exceed 144,000.[25] [25] _Sketches of Imposture, Deception, and Credulity_. Second Edition. 1840.