learning the Practice will be attended with some Advantages; for as the Learner will fee on what particular Theorems each Part of it is founded, he will be the more folicitous of understanding them when Time and Opportunity will permit, and by that means render himself a complete Artist. As the Accuracy of Tables made Ufe of in Calculation is a Matter of the last Importance, so I have been very careful in correcting those contained in this Treatise; in order to which I not only carefully examined the Copy before it went to the Press, but also re-examined, very attentively, every Sheet before it was printed off; whence I have Reason to hope that they are entirely correct, and, confequently, the Practitioner may fafely rely on them without the least Danger of being deceived. The The CONTENT S. CHAP. Ι. Elements of Chronology, from Page 1 to Page 13. T HE Division of Time and its Parts What a Solar and Lunar Month is What Bissextile or Leap-year is, and by whom introduced -- Page 2 3 4 ibid 4 5 What the Cycle of the Sun is, and how it may be found-6 What the Metonic Cycle, or Golden Number is, and how to find it Why Easter is often celebrated at a different Time from what 7 9 ibid. --10 II 12 What the great Julian Period is, and the Methodof finding it 13 CHAP. II. Of the Flux and Reflux, or the Flowing and Elbing of the Sea. from page 13 to 21 How to find the Time of High-water on the Full and Change An Alphabetical Tide-Table of the most remarkable Sea- The Method of finding the Time of High-water any Day of 13 14-19 19 The Construction and Use of an Univerfal Tide-Table-20 99-106 2. The Stereographic Projection of the Sphere - 106-114 3. The Solution of fuch Astronomical Problems as CHAP. VII. The Description, Construction, and Use of fuch Instruments as are necessary in Navigation. from P. 135 to 149. Method of finding the Difference of Longitude between two Places 157-159 5. Of the Nature of the Rhumb-Line 159-160 170-174 Sect. 9. The Doctrine of Oblique-angled Plane-Tri- angles applied to Problems of Sailing-174-177 10. Of Sailing in a Current, with the Method of finding its Setting and Drift - 11. Of Sailing under a Parallel What Reasons induced the Mathematicians at first to believe that the Earth was not a A Solution of several of the preceding Theorems - A Table of the Length of the Arches of the |