In January 1844, William John Vernon gave a lecture in Greenwich that provoked ‘extraordinary uproar’. He placed a young woman into a trance, and doctors were unable to rouse her. She was not dead, but in a mesmeric coma, and seemingly oblivious to the strong ammonia that they were waving beneath her nostrils. Vernon then raised the woman's arm until it was horizontal to the floor, and it remained in position, in a state of catalepsy. He was planning to exhibit greater feats than these – demonstrations of phreno-mesmerism, insensibility to pain, and even clairvoyance – but that was when the ‘extraordinary uproar’ began, and everyone had to go home early. It is a minor episode in the history of extraordinary phenomena, but it is worth a closer look because it can tell us a great deal about the bigger picture. After all, the bigger picture is merely the sum of all the little episodes, and we are interested in what they have had in common. As we shall see, what happened in Greenwich was fairly typical (in certain key respects) of how mesmeric phenomena were demonstrated and reported.

How this was done matters because beliefs about mesmerism were responses to demonstrations and reports of mesmeric phenomena. If we wish to understand such beliefs, then we need to consider the reported events to which people were responding. The demonstrations themselves are long gone, of course, so our only access is through reports of them, and these reports did not merely describe the events, but described them in a particular way. By examining them, we can form a general idea of what happened at the demonstrations, and we can see in detail how they were framed by contemporary reporters for the wider public. In doing so, we can see how the performance and reporting of mesmeric phenomena were fundamental to beliefs about mesmerism, and we can begin to identify various patterns that have been part and parcel of extraordinary beliefs since.