Iron

"This work of Dr Gilbert's relates chiefly to the , and what we call magnets; that is, pieces of steel which have acquired properties similar to those of the loadstone. But he extends the term magnetism and the epithet magnetic, to all bodies which are affected by loadstones and magnets, in a manner similar to that in which they affect each other. In the course of his investigations, indeed, he finds that these bodies are only such as contain iron in some state or other; and in proving this limitation he mentions a great variety of phenomena which have a considerable resemblance to those which he allows to be magnetical, namely, those which he called electrical, because they were produced in the same way that is made to attract and repel light bodies. He marks, with care, the distinctions between these and the characteristic phenomena of magnets. He seems to have known, that all bodies may be made electrical, while ferruginous substances alone can be made magnetical."

"Amongst the many other ingenious contrivances frequently alluded to in his book, Gilbert mentions the versorium, an iron needle moving freely upon a point, with which he was enabled to measure excited electricity. He is besides the inventor of "two most ingenious and necessarie Instruments for Sea men to find out thereby the latitude of any place upon sea or land, in the darkest night, that is without the helpe of Sunne, Moone or Starre." These instruments are described in Thomas Blunderville's quarto work entitled "The Theoriques of the seven Planets, shewing their diverse motions... printed at London 1602.""

"By the publication in 1600 of the ' of Dr. William Gilbert the science of electricity was founded. ...Trying the properties of s in innumerable experiments lasting over many years, he was led to several notable discoveries, and to one generalization of immense importance. He discovered the augmentation of the power of a by arming or capping it with soft iron cheeks. Gilbert called such a cap an armatura..."

"On taottava silloin kun rauta on kuuma."