ing the Eye right to the Inftrument; and, thirdly, the Refraction is not confidered. PROPOSITION VI. From what precedes it appears, that the Methods which Sailors ufe to find the Ship's Place are in the Chart uncertain, on account of the uncertainty as to the Point failed in, and of the Miles run, and of the obferved Latitude; yet the Obfervation of the Latitude of the Place come to, is lefs liable to Error, especially in calm Weather, and a clear Sky, and may be corrected. BUT from this alone we cannot find the Ship's Place, but, as was at large delivered, in Chap. xxx. there must be another Datum, viz. either the Diftance from the Place left, or Point failed in, or the Difference of the Longitude left, and come to; and therefore the Longitude of the Place come to, which, with the Latitude, is again wanted, determines the Ship's Place. HENCE it appears, that the Art of Navigation is to be perfected by the Solution of this Problem; To find, at any Time, The Longitude of a Place at Sea. A public Reward is promised for the Discovery; let him obtain it who is able. INDEX. INDE X. A Dmiralty Ilands 116 America, how encompaffed 177 Egean Islands ibid. Ætna 439 143, 144 ibid. certain Places 472,476 Aifne, it's Inundation 344 Alexander, fruftrated in tranfporting his Army Alps 251 135 Altitude of the Earth and Wa Archimedes, his Demonstration Ariftotle, his Opinion of the O- Arms of Rivers 226 Afcenfion, what 113 Afcenfion Ifland Cc 314 298 664 154 Ajcii, |