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BARLOW, William. Magneticall Aduertisements: or divers pertinent obseruations, and approued experiments concerning the nature and properties of the Load-stone... most needfull for practise, of trauelling, or framing of Instruments fit for Trauellers both by Sea and Land. London: Edward Griffin for Timothy Barlow, 1616.
Small 4o (126 x 174 mm). With the errata leaf, printer's woodcut device on title (McKerrow 380), woodcut diagrams. (One diagram and some headlines cropped.) 18th-century quarter calf, marbled boards (upper cover starting); quarter morocco slipcase. Provenance: Harrison D. Horblit (bookplate; his sale part I, Sotheby's London, 10 June 1974, lot 83).
FIRST EDITION. By the time of the publication of this book, Barlow had researched magnetism for some forty years. He was particularly interested in the manufacture and maintenance of the sea-compass. The above work contains his fundamental discovery, the directional properties of the compass-needle. Barlow "designed navigating instruments, polar charts, and compasses. He explained the difference between iron and steel needles; improved the needle's shape; made an easily removable card so the needle could be easily remagnetized; gave instructions as to the best method of remagnetizing the needle by stroking it with the lodestone three or four times from the needle's center to the ends, using the north end of the lodestone for the needle's north end, and the south for the south. He also designed an azimuth compass for measuring the variations which happened to be an improvement on the instrument designed by Norman and Borough; it was a compass with sights and a verge ring marked in degrees, the first such compass, and was to be used by grateful seamen for over two hundred years" (Gurney Compass, a Story of Exploration and Innovation, New York, 2004 p.64). VERY RARE. STC 1442; Taylor Mathematical Practitioners 129; Wheeler Gift 89.
Small 4
FIRST EDITION. By the time of the publication of this book, Barlow had researched magnetism for some forty years. He was particularly interested in the manufacture and maintenance of the sea-compass. The above work contains his fundamental discovery, the directional properties of the compass-needle. Barlow "designed navigating instruments, polar charts, and compasses. He explained the difference between iron and steel needles; improved the needle's shape; made an easily removable card so the needle could be easily remagnetized; gave instructions as to the best method of remagnetizing the needle by stroking it with the lodestone three or four times from the needle's center to the ends, using the north end of the lodestone for the needle's north end, and the south for the south. He also designed an azimuth compass for measuring the variations which happened to be an improvement on the instrument designed by Norman and Borough; it was a compass with sights and a verge ring marked in degrees, the first such compass, and was to be used by grateful seamen for over two hundred years" (Gurney Compass, a Story of Exploration and Innovation, New York, 2004 p.64). VERY RARE. STC 1442; Taylor Mathematical Practitioners 129; Wheeler Gift 89.