Page:Philosophical Transactions - Volume 004.djvu/64

 any place to the East or West. And i by any notable mischance or carelesness all the Watches should come to stand still, yet you may at any place, whereof the Longitude is certainly known, set them a going again, and adjust them there by the Sun, and so reckon the Longitudes from that same Meridian. For, you are to know, that you are nor at all oblig'd to put one certain Meridian of any knowne place as a begining of the Longitude-reckoning; this hapening only in Mapps, or Tables of Longitude: As, when you take for that purpose the Meridian of the Pico in Teneriffe, or that of the Islands of Corvo and Flores (the most Westerly of the Azores) or any others. Yet it were very fit, that all Geographers agreed and pitched upon one and the same First Meridian, that so all places might be known by the same Degrees as well of Longitude as of Latitude; though in Voyaging it is sufficient, to observe only the difference of Longitudes, beginning to reckon from the Meridian of any place, you please, as if it were the first.

If it happen, that being at Sea all the Watches stopp, you must, as speedily as is possible, set them a moving again, that you may know, how much you advance from than place towards the East or West: Which is of no small importance, since, for want of this knowledg, you are sometimes by the force of Currents so carried away, that though you saile before the Wind, yet you are driven a Stern; of which there are many Examples.

The Watches being distinguisht by marks as A. B. or the like, every day about Noon, or when most conveniently you can, observe the time of the day by the Sun, or by the Starrs at night, and subduct thence the minuts and seconds, that are adjoyn'd to that day in the Table, and write the remainder down in a paper, wherein 9. Columns or more are mark't, placing them in the second column, having plac'd the day of the Month in the first. And at the same time write down the hours, minutes and seconds of each Watch in a distinct Column, all Rh