In the introduction Molyneux pointed out that up to then there was nothing written in the English language on that part of mathematics and, he said, “I am sure there are many ingenious Heads, great Geometers, and Masters in Mathematics, who are not so well skilled in Latin.” And certainly Molyneux was right, for the use of the modern languages was expanding constantly in that period.
Molyneux had a low regard for Zahn, whom he called “a blind transcriber from others” and asserted that he copied the errors of de Chales.
An early section of the book was “On the Representation of outward objects in a Dark Chamber; by a Convex Glass.” This was a modified version of the natural camera, first set down carefully by da Vinci and dating back to Roger Bacon.
Molyneux devoted a whole section to “The Explication of the Magick Lantern, sometimes called Lanterna Megalographica” (that last was one of the names Kircher gave to it). Molyneux scientifically described a good model featuring a metal lantern and adjustable lenses. He explained that the pictures to be shown were painted with transparent colors on pieces of thin glass which were inverted and placed in the projector. His comment on the type of picture is entertaining: “This is usually some Ludicrous or frightful Representation, the more to divert the Spectators.” “Horror” pictures—and comedies—were born centuries before Hollywood.
Also discussed were focusing lenses, glass and concave mirrors, adjustments in the picture focus, the throw from projector to the screen.
However, Molyneux wished to keep strictly on the scientific and scholarly side saying, “As to the Mechanick Contrivances of this Lantern, the most Convenient Proportion of the Glasse, etc. this is so ordinary amongst the common Glass Grinders that ’tis needless to insist further thereon in this place. ’Tis sufficient to me that I have explained the theory thereof.”
At the end of the volume there was an advertisement—it was noted that all the instruments mentioned “are made and sold by John Yarwell at the Archimedes and Three Golden Prospects, near the great North Door in St. Paul’s Church-Yard: London.” This makes John Yarwell the first recorded commercial dealer in the magic shadow science.
In addition to Schott, Milliet de Chales, Zahn and Molyneux, many travelling showmen such as Walgenstein, the Dane, introduced the magic lantern and its magic shadow shows in great cities and little hamlets of Europe. Some were professional entertainers, accepting the projector as a new device; others were the “vagabonds and imposters,” of the type condemned by Kircher. This group recognized no law and copied and appropriated the magic lantern projector whenever opportunity presented itself. There was no copyright or other protection to restrain them. By the early part of the 18th Century the magic lantern was commonplace and many men were skilled in its use.