\subsection{The Magic Lantern}

The 'magic lantern' is an early slide projector. People have been projecting images using concave mirrors and pin-hole cameras (camera obscura) since Roman times\footnote{\BrHeardWPPY{}, 21}. But glass lens technology wasn't sufficiently developed to make slide projectors (or telescopes) until the 17th century. The first allusion to a 'magic lantern' is by Dutch scholar Christiaan Huygens (1629\EnDash{}1695) in the 1650s and he is generally credited with inventing it\EmDash{}though he didn't want to admit it, considering it frivolous.\footnote{\BrHeardWPPY{}, 35}  Whether he had actually invented it or not, Huygens introduced this curiosity to Thomas Walgenstein who realized its commercial value for entertainment and traveled through Europe\EmDash{}mostly France and Italy\EmDash{}demonstrating his machine to foreign princes and selling them replicas for their own amusement. In 1665 Walgenstein showed the device to Athanasius Kircher who described in his book \Title{Ars Magna Lucis et Umbrae} (Great Art of Light and Shadow) published in 1671.\footnote{\BrHeardWPPY{}, 35}
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	Kircher's &quot;Magic Lantern&quot;</i>
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Until 1783 the only light source was lamps burning sperm or colza oil\EmDash{}not very bright at all, so images could only be projected for very small audiences. But in 1783 the Argand lamp was invented, which was considerably brighter, and the magic lantern really started coming into its own. \footnote{\BrHeardWPPY{}, 38ff.}

Others used the magic lantern in s\'{e}ances and ghost shows, notably Johann Schr\"{o}pfer (1730\EnDash{}1774) and Paul de Philipsthal (??\EnDash{}1829).\footnote{\BrHeardWPPY{}, passim}

