Francis Line's magnetic clock Site map
Timeline
Reconstruction
Acknowledgements

 
 

Francis Line's Magnetic clock, from Sylvestro Pietrasancta, De Symbolis Heroicis, Antwerp, Ex officina Plantiniana Balthasaris Moreti, 1634. 

(click on the image for an enlargement)

 The version of the magnetic clock that first caught the attention of European literati was created by the English Jesuit Francis Line in the Belgian town of Liège. Line showed his clock to the Papal Nuncio to Cologne,  Monsignor Pierluigi Caraffa, who was visiting Liège in the company of his Jesuit confessor, Sylvestro Pietrasancta. Caraffa took Lineās clock to his house, and observed it for several days, finding that it kept very accurate time. When Godefrid Wendelin inquired of Line whether there was anything inside the sphere that caused it to rotate, Line just shrugged his shoulders, "sufficiently damning my incivil curiosity in this way", as Wendelin later reported to Gassendi.

Pietrasancta included the following description of the clock in his book of personal emblems, De symbolis heroicis, published in Antwerp in 1634, with a frontispiece designed by Rubens:
 
Recently at Liège, P. Franciscus Linus, a mathematics instructor in the English College of our Society, devised most successfully this orb, which is placed inside a glass phial, which orb stays in the centre of the surrounding water (just as the Earth stays in the centre of surrounding air) by a secret balancing of its mass. But the orb by an arcane force and as if by a certain love strives after the conversion of the sky from east to west and is driven around altogether in the space of 24 hours. 

A little fish is placed inside as indicator, and like an expert swimmer, its weight poised, watches the fleeting hours and designates them with its snout, its eyes gazing intently on them. When the phial is moved, if impetus is given to the water, soon by its own will it regains the path of its orb; and the calculation of time will be wholly unaltered after tranquillity is restored. Also the indicator placed in the vessel in like manner shows the hours. And it imitates the sun in his sphere, and indeed follows the sun in the East, on the meridian, in the West [· ] It will hasten [to the sun] ever so quickly since love knows no delay; and although it may leap back and forth several times, finally it will obtain that position to which, as a comrade and fellow traveller of the Sun, it will return without fail.

 

Website created by Michael John Gorman, April 2001. Comments, questions or suggestions to mgorman@stanford.edu