=References.=--A. Watt, “Bibliotheca Britannica,” Vol. II. p. 804, at p. 75_g_ Vol. I. of which (article, “Wm. Barlowe”) is “A briefe discovery of the idle animadversions of Marke Ridley, M.D.,” upon a treatise entitled “Magneticall Advertisements,” London, 1618. Consult also “The Lancet” of August 7, 1897, p. 349; Munk’s “College of Phys.,” Vol. I. p. 106; Ridlon’s “Ancient Ryedales,” p. 425. =A.D. 1616.=--Schouten (Guillaume Cornelissen--Willem Cornelisz), Dutch navigator, indicates points lying in the midst of the Pacific and south-east of the Marquesas Islands in which the variation is null. Humboldt alludes to this (“Cosmos,” 1859, Vol. I. p. 182, and Vol. V. p. 59) and says, “Even now there lies in this region a singular, closed system of isogonic lines, in which every group of the internal concentric curves indicates a smaller amount of variation.” For Schouten, consult “Relation,” published by Aris Classen, Amst., 1617; Larousse, “Dict. Univ.,” Vol. XIV. p. 375. Under this same date, A.D. 1616, Chas. Pickering tells us that Wm. Baffin (Churchill Coll. and Anders. II. 268) continued North to “seventy-eight degrees,” as far as a Sound called by him “Thomas Smith’s,” where the compass varied “fifty-six degrees to the westward,” making the true North bear N.E. by E. The northern expanse of water received the name of “Baffin’s Bay” (“Chron. Hist. of Plants,” Boston, 1879, p. 933). =A.D. 1617.=--Strada (Famianus), an Italian author and Jesuit priest, publishes his curious “Prolusiones Academicæ,” wherein he describes (lib. ii. prol. 6) a contrivance consisting of two magnetic needles attached to two dials each bearing a circle of letters so arranged that when one needle is made to point to any letter on one dial, the other needle points to the same letter upon the other dial.