In Search of Sir Thomas Browne by Hugh Aldersey-Williams

Author:Hugh Aldersey-Williams
Language: eng
Format: epub
Publisher: W. W. Norton & Company

electricity (PE, 1646): Browne’s lithe visual imagination yields him some uncanny insights into these mysterious new phenomena. Drawing an analogy with the circular motion observed when one blows on motes of dust in sunlight, he gives us a compelling picture of electric field lines that would not be properly mapped until Michael Faraday’s work two centuries later. He all but gives a statement of the inverse square law of magnetic and electrical attractions: ‘a tenuous emanation or continued effluvium, which after some distance retracteth into it self’. Ice, he intuits correctly, is generally less transparent than crystals of salt or saltpetre because ‘Its atoms are not concreted into continuity’.

For many of his readers, this is their first chance to understand the new discoveries about magnetism set out (in Latin) by William Gilbert’s De Magnete of 1600. (Indeed, a large part of Browne’s project in Pseudodoxia Epidemica is to present in ordinary English knowledge both ancient and modern previously only available in Latin.) But they have the added spice of Browne’s own confirmatory experiments. One of these Browne devised in order to challenge the belief that two needles stroked with the same magnet would point to the same letter of the alphabet when set to pivot at the centre of respective abecedary circles. ‘The conceit is excellent, and if the effect would follow, somewhat divine,’ Browne marvels. He can see how a pair of such devices might work like a wireless telegraph. But will they? He constructs two circles of wood, which he marks with the letters of the alphabet. He then takes two needles made of the same steel and touched with the same magnet. He places the two wheels close to one another and moves the needle of one of them. The other does not respond; it stands unmoved ‘like Hercules pillars’. He cannot disguise his disappointment. But ocular proof and reason prevail, and he reasons further that the devices would not work for sending messages in any case as the movement of the needle from A to B on one wheel would be echoed by an opposing rotation, that is from A to Z, on the other.

Explaining invisible phenomena is one of the urgent tasks for early modern scientists. In 1646, it is magnetism, electricity, and the worlds at different scales made visible for the first time by the invention of the telescope and the microscope. Soon, it will be Newton on gravity and light.

Browne makes the first use in English of the word ‘electricity’ when he writes that ‘Crystal will calefie unto electricity’, in other words that a suitable material when rubbed and warmed by friction will acquire a static electrical charge. He goes on to puzzle as to why only some materials behave in this way, and what the respective properties are that the attractor and the attracted bodies must possess, and what it is that actually passes between them when this happens.

deductive (PE, 1646): Although he coins the word as a loose synonym for ‘derivative’

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.