A treatise of artificial magnets : in which is shewn an easy and expeditious method of making them, superior to the best natural ones: ... By J. Michell. - Michell, John, (printed by J. Bentham; and sold by W. & J. Mount & T. Page, J. & P. Knapton, C. Bathurst, London; W. Thurlbourn, and J. Merrill, in Cambridge; J. Hildyard at York, and J. Fletcher at Oxford,, 1750)