Specula Melitensis Encyclica

Specula Melitensis Encyclica (“The Maltese Watchtower”) is a 1638 book by Fra Salvatore Imbroll, describing a machine invented by a Jesuit scholar Athanasius Kircher.

It was printed in Naples by Secundino Roncagliolo[1] and dedicated to Giovanni Paolo Lascaris, Grand Master of the Knights of Malta.

The machine was a combination mechanical calculator and a reference of contemporary scientific knowledge related primarily to astronomy, astrology, and medicine.

The intended meaning is explained in the first paragraph of the book: This machine of ours is called Specula Melitensis both because of the similarity of its shape and form to that of a watchtower, and because, as from any watchtower, all in the circumference of the Horizon, being exposed far and wide, is revealed to an encounter, likewise as from this Specula, quicker than word, anything pertaining to Astronomy, Geography, Hydrography, Physics, and Medicine is revealed to the eye.

[2] The book opens with a dedication to Johannes (Giovanni) Paulus Lascaris, and a credit to the machine's creator, "the most erudite" Athanasius Kircher.

The third side has in its middle a large wheel displaying the sunrise and sunset times, the sun's declination, star culminations, and other astronomical data by year, month, and day.

The three wheels display Moon phases and astrological signs with their application to matters of agriculture, medicine and navigation, and physiognomical information.

[6] Importantly for the plot, in the novel the third side of the Cube contains a Horologium Catholicum (not found in the original), which shows the local time at any Jesuit mission in the world.