Directions for Sea-men, bound for far Voyages.
It being the Design of the R. Society, for the better attaining the End of their Institution, to study Nature rather than Books, and from the Observations, made of the Phænomena and Effects she presents, to compose such a
History of Her, as may hereafter serve to build a Solid and Useful Philosophy upon; They have from time to time given order to several of their Members to draw up both Inquiries of things Observable in forrain Countries, and Directions for the Particulars, they desire chiefly to be informed about. And considering with themselves, how much they may increase their Philosophical stock by the advantage, which England injoyes of making Voyages into all parts of the World, they formerly appointed that Eminent Mathematician and Philosopher Master Rooke, one of their Fellowes, and Geometry Professor of Gresham Colledge (now deceased to the great detriment of the Common-wealth of Learning) to think upon and set down some Directions for Sea-men going into the East & West-Indies, the better to capacitate them for making such observations abroad, as may be pertinent and suitable for their purpose; of which the said Sea-men should be desired to keep an exact Diary, delivering at their return a fair Copy thereof to the Lord High Admiral of England, his Royal Highness the Duke of York, and another to Trinity-house to be perused by the R. Society. Which Catalogue of Directions having been drawn up accordingly by the said Mr. Rook, and by him presented to those, who appointed him to expedite such an one, it was thought not to be unseasonable at this time to make it publique, the more conveniently to furnish Navigators with Copies thereof. They are such, as follow;
1. To observe the Declination of the Compass, or its Variation from the Meridian of the place, frequently; marking withal, the Latitude and Longitude of the place, wherever such Observation is made, as exactly as may be, and setting down the Method, by which they made them.
2. To carry Dipping Needles with them, and observe the Inclination of the Needle in like manner.
3. To remark carefully the Ebbings and Flowings of the Sea, in as many places as they can, together with all the Accidents,
Ordinary and Extraordinary, of the Tides; as, their precise time of Ebbing and Flowing in Rivers, at Promontories or Capes; which way their Current runs, what Perpendicular distance there is between the highest Tide and lowest Ebb, during the Spring-Tides and Neap-Tides; what day of the Moons age, and at times of the year, the highest and lowest Tides fall out: And all other considerable Accidents, they can observe in the Tides, cheifly neer Ports, and about Ilands, as in St. Helena's Iland, and the three Rivers there, at the Bermodas &c.
4. To make Plotts and Draughts of prospect of Coasts, Promontories, Islands and Ports, marking the Bearings and Distances, as neer as they can.
5. To sound and marke the Depths of Coasts and Ports, and such other places nere the shoar, as they shall think fit.