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 Joseph Bentham; and sold by W. and J. Mount, and T. Page, J. & P. Knapton, C. Bathurst, J. Beecroft, London; W. Thurlbourn, and T. Merrill, in Cambridge; J. Fletcher, at Oxford; and J. Hildyard, at York,, 1751)