During the next two decades, performances using the illusion spread to several countries. In 1877 a patent was registered for the United States. In Britain, theatre productions using Pepper’s Ghost toured far outside major cities. The performers travelled with their own glass screens and became known as “spectral opera companies”. Around a dozen such specialist theatre companies existed in Britain. A typical performance would comprise a substantial play where apparitions were central to the plot, like an adaption of Dickens’ "A Christmas Carol," followed by a short comic piece which also used ghost effects. One company, for instance, ‘The Original Pepper’s Ghost and Spectral Opera Company’ had 11 ghost-themed plays in its repertoire. Another such company during a single year, 1877, performed at 30 different places in Britain, usually for a week but sometimes for as long as six weeks. By the 1890s, however, novelty had faded and the vogue for such theatre was in steep decline. Pepper’s Ghost remained in use however at sensational entertainments comparable to ‘dark rides’ or ‘ghost trains’ at modern funfairs and amusement parks: survives of audience participation in two macabre entertainments, which both used Pepper’s Ghost, within a ‘Tavern of the Dead’ show which visited Paris and New York in the 1890s.