A Trespass of Swine

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Considerations of humanity and hogritude, because an insufficiency of pigs is one of the great faults of all that the gods have made manifest to man.

Building a Learned Pig – Pinchbeck and The Expositor

Some contend it is witchcraft ; and others, like the ancient Pythagoreans, believing in the transmigration of souls, conclude that the spirit of the grunting philosopher might once have animated a man.

The Expositor. LETTER I., From A. B. to W. F. P.

The Pig of Knowledge or Learned Pig

The Reprint Series of Porkopolis.org
The Expositor by William Frederick Pinchbeck
available in PDF format or as a web page.

The Expositor; or Many Mysteries Unravelled was one of the first works on magic published in the United States. Published in 1805, it was the first book length expose of conjuring tricks written by a professional magician. It provided readers with explanations and printed instructions for the creation and performance of many marvels then popularly in use by illusionists, conjurers and showmen, including how to create a Learned Pig.

The author of The Expositor, William Frederick Pinchbeck (fl. 1800s), was an American, born in England. Pinchbeck was a descendant of a well known English family of master craftsmen and clock makers, also known for their musical automata as well as automata designed and made for European conjurers, illusionists and showman.

Pinchbeck claimed that his intention in writing the book was to amuse and instruct interested readers, and, as stated in his introduction, “also to convince superstition of her many ridiculous errors.”

A substantial portion of The Expositor involves Pinchbeck explanation of how to train a pig to perform with a handler in the illusion of the “Pig of Knowledge” also know as a “Learned Pig”. The Expositor is also commonly referred to as ‘The Pig Book’ due to the woodcut of a pig in the book’s frontispiece and to Pinchbeck’s thorough explanation of the learned pig effect.

Also explained are the Acoustic Temple, the Philosophical Swan, and many other early conjuring feats. All Pinchbeck’s explanations are in the form of a series of letters between the author, “W. F. P.” (William Frederick Pinchbeck), and an unknown (and most-likely imaginary) friend, “A. B.”.

This format allows Pinchbeck to present his explanations as lessons given through the letters exchanged between the two friends. Questions asked in one letter from “A. B.” are answered in the next as a lesson provided by “W. F. P.”.

Pinchbeck’s The Expositor is presented here as part of the Porkopolis Reprint Series. This collection contains significant, but difficult to find, pig-themed print materials. It provides visitors with accurate and searchable reprints in a modern presentation format that also retains some of the experience and enjoyment of reading the original document.

The Expositor is available through Porkopolis in PDF format or as a web page.

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  1. Very glad to discover your excellent website — and thanks for the mention of PYG!

    There’s a good deal more about learned pigs, and Pinchbeck, on my old blog for the novel.

    Very glad to make your acquaintance!


    1. Thanks for visiting, Russell. Your novel, Memoirs of Toby, the Learned Pig, is a favorite here.


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