The cracking of joints was the theory scientists and skeptics most favored to explain the rappings, a theory dating back to 1850. The physician E. P. Longworthy investigated the sisters and noted how the knockings or raps always came from under their feet or when their dresses were in contact with the table. He concluded that Margaretta and Kate had produced the noises themselves. John W. Hurn who published articles in the "New-York Tribune" also came to a similar conclusion of fraud. The Reverend John M. Austin would later claim the noises could be made by cracking toe joints. The Reverend D. Potts demonstrated to an audience that the raps could be made by this method.