The pasilalinic-sympathetic compass, also referred to as the snail telegraph, was a contraption built in an attempt to prove the misguided hypothesis that snail

Snail

Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...

s create a permanent telepathic

Telepathy

Telepathy , is the induction of mental states from one mind to another. The term was coined in 1882 by the classical scholar Fredric W. H. Myers, a founder of the Society for Psychical Research, and has remained more popular than the more-correct expression thought-transference...

 link when they touch. The belief was developed by French

France

The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

 occult

Occult

The word occult comes from the Latin word occultus , referring to "knowledge of the hidden". In the medical sense it is used to refer to a structure or process that is hidden, e.g...

ist Jacques Toussaint Benoit and colleague Monsieur Biat-Chretien in the early to mid 19th century.

The supposed telepathic bond between the two snails was imagined to have no physical limit, thus making communication possible over any distance. By touching one half of the snail partnership it was suggested that the other snail would sense the contact and would move. Benoit built an apparatus to test his theories, but it quickly became apparent that what he expected to be a communication revolution was in fact just a costly failure.

The theory

Benoit and Biat-Chretien believed that when there is contact between two snails a special type of fluid forms a link between them. This fluid forms an invisible thread that keeps the snails in "sympathetic communication" by using animal magnetism

Animal magnetism

Animal magnetism , in modern usage, refers to a person's sexual attractiveness or raw charisma. As postulated by Franz Mesmer in the 18th century, the term referred to a supposed magnetic fluid or ethereal medium believed to reside in the bodies of animate beings...

 caused by an electric current pulsating along it. Though this implies some form of physical link between the two snails it was still referred to as "telepathy".

Making a working model

Benoit did not have enough financial support to build his design. Benoit persuaded the Monsieur Triat, manager of a Paris gymnasium, to give him lodgings and an allowance, having impressed upon him the importance of his discovery. After a year Triat's patience grew thin and he demanded to see a working model.

The apparatus

The apparatus consists of a square wooden box containing a large horizontal disc. In the disc are 24 holes, each containing a zinc dish lined with a cloth soaked in a copper sulphate solution; the cloth was held in place by a line of copper. At the bottom of each of the 24 basins is a snail, glued in place, and each associated with a different letter of the alphabet. An identical second device holds the paired snails.

To transmit a letter the operator touches one of the snails. This causes a reaction in the corresponding snail which can be read by the receiving operator.

Demonstration

On 2 October 1851 Benoit invited Triat and friend Jules Allix

Jules Allix

Jules Allix was a feminist, socialist, and eccentric inventor linked to the Paris Commune.- Political activism :...

, a journalist from La Presse. He first asked Triat and then Allix to stand at one station and to spell out a word - he would then tell them what the word was by reading from the receiving end. However, he continually walked between the two devices and Triat began to suspect that it was a hoax. Allix was convinced by the demonstration and he wrote an article full of praise for Benoit's creation which appeared in the newspaper on 27 October 1851. Triat demanded a second, stricter test to which Benoit agreed. When the time came though Benoit had vanished.

Coverage

Along with the Allix article in La Presse the story of the pasilalinic-sympathetic compass was covered by the 1889 book Historic Oddities and Strange Events by Sabine Baring-Gould

Sabine Baring-Gould

The Reverend Sabine Baring-Gould was an English hagiographer, antiquarian, novelist and eclectic scholar. His bibliography consists of more than 1240 publications, though this list continues to grow. His family home, Lew Trenchard Manor near Okehampton, Devon, has been preserved as he had it...

.

See also

• Snail mail
  Snail mail
  Snail mail or smail is a dysphemistic retronym—named after the snail with its slow speed—used to refer to letters and missives carried by conventional postal delivery services. The phrase refers to the lag-time between dispatch of a letter and its receipt, versus the virtually instantaneous...
  
   – a disparaging name for the postal
  Mail
  Mail, or post, is a system for transporting letters and other tangible objects: written documents, typically enclosed in envelopes, and also small packages are delivered to destinations around the world. Anything sent through the postal system is called mail or post.In principle, a postal service...
  
   system
• Den Den Mushi – the "Transponder Snail Phone" in the Japanese comic and animated series, One Piece
  One Piece
  is a Japanese shōnen manga series written and illustrated by Eiichiro Oda. It has been serialized in Weekly Shōnen Jump since August 4, 1997; the individual chapters are being published in tankōbon volumes by Shueisha, with the first released on December 24, 1997, and the 64th volume released as...