How did Francis Drake navigate his ship when in 1577 he embarked upon his famous voyage round the world ? Strictly speaking he did not navigate her, for the task was delegated to subordinate officers. The Pelican (or Golden Hind as she was later renamed) carried, as was customary, a master and a pilot whose duty it was to make the necessary observations and lay the ship upon her course. But these had signed on for a supposed voyage to Alexandria to load currants, and Drake knew well enough that no English pilot could then compare with a pilot of Spain or Portugal, whether in training, experience or equipment: for these nations, as pioneers of the Great Discoveries, had also taken the lead in the development of nautical science and in the formal schooling of seamen. That explains why Captain Francis furnished himself with the latest chart from Lisbon, and why, when he reached African waters, he kidnapped a Portuguese pilo to sail him into the Pacific, only to maroon the unfortunate man in Central America when he had served his turn and a Spaniard was indicated for the next stage of the voyage. Hitherto no English ship had left the Atlantic, and apart from a few men trained in the Muscovy Company's service the average English sailor laughed at the idea of navigating with charts and instruments. He had his compass, he knew his landmarks, and once he was in soundings he could cast the lead and feel his way into harbour blindfold. To see a man ‘shooting the Sun’ (as it was already termed) with a cross-staff was an occasion for mockery. ‘Have you strook it?’ he would cry, ‘Have you strook it?’ And as for charts, he wanted none of your sheepskins, he could make his voyage as well upon a board! It was upon a prepared sheepskin that the mediaeval charts were drawn and painted, the neck to the left, while the ‘board’ was the traverse-board marked with the thirty-two rhumbs. These were pierced with holes at regular intervals, into which pegs were inserted at each turn of the sand-glass, thus recording the time sailed on any particular point of the compass.

The design of an almanac is a highly technical matter in which principles may have to yield to practical detail. In order that the proposals shall be fully appreciated and fairly discussed the basic principles that have led to the present proposals, and their practical alternatives, will be indicated as briefly and as objectively as possible.

In the Nautical Almanac Office we have much experience in the presentation of astronomical and numerical data; but we are not navigators and we have little experience of the practical use of the Abridged Nautical Almanac. While all criticisms will be welcomed, those relating to practical requirements will therefore be particularly valuable.

The purpose of this lecture is to review briefly the many methods at present available for the reduction of astronomical observations, and to make suggestions for the future. The main conclusion will be that altitude-azimuth tables provide the simplest and quickest method of reducing a sight.

It should be made clear that this is not a comprehensive survey setting out to examine and criticize every method; the bibliography of papers and tables (itself incomplete) published by H. Bencker in The Hydrographic Review, which contains some 1200 references, indicates that such a task would demand months of research. Attention is directed towards the principles of the various methods, and the limitations of each principle are discussed independently of the actual tables existing for the application of the method.

The questionnaire shown below was circulated to all members of the Institute. In the following analysis of the replies, forms completed by members with no experience or direct concern with surface navigation have been disregarded. The substance of replies received from members in the Royal Navy has been given separately. It has not been possible to detect any marked unanimity in the answers given by Examiners, Navigation School instructors, Marine Superintendents,&c., and these have been included under the heading of Merchant Navy.

The detailed comment given is taken from the discussion at the Meeting and from letters and memoranda sent in to the Institute. In some cases it refers (e.g. layout, &c.) to matter not reproduced in the Journal. For convenience of reading reference numbers have been given to the authors of comment.

The paper discusses the way in which the accuracy provided by different navigation systems can best be presented diagrammatically, and it is concluded that contours of constant 95% radial error give the best general picture of a system. Where a more detailed picture is required error ellipses can be added at suitable points in the system. The 95% radial error of fixing is calculated for radial, rθ, azimuthal and different hyperbolic systems, and graphical methods are developed for drawing contours along which the 95% error is constant, and also for drawing 95% ellipses. Diagrams show typical results for the different systems.

In a recent issue of Nature Sir Charles Goodeve gave an illuminating account of the value of operational research in war and described how, in peacetime, similar methods were being applied to problems of rail and road traffic. It is significant that he was unable to give examples of similar investigations into the flow of air traffic.

The paper is divided into two parts. The development of ship-borne compasses is reviewed in Part I; in this section some of the difficulties due to bad siting, &c., are mentioned and certain solutions such as the use of repeating compasses and improved methods of correction are described. Part II surveys the development of the aircraft compass and shows how its phases of development have corresponded to those of the marine compass. Some recent forms of aircraft compass and methods of development are also described.

Twenty years ago meteorological forecasting was necessary and important to aviation. A number of factors made it so, as a short review of flying conditions in those days will show.

The weather was then the dominant factor in training. The wingloading of training aircraft was then so light that a sudden variation of only 10 m.p.h. in the wind made a practice landing hazardous. Both pupil and instructor therefore anxiously awaited the weather forecast. The wind forecast was equally important to the transport pilot of 1928 when a headwind of 60 m.p.h. was likely to prevent his reaching a destination only 200 miles away.

On page 179 of the first volume of the Journal, Commander J. Middendorp, R.N.N.R., discusses the effect on the observed altitude that arises when the sextant is tilted out of the vertical plane, and concludes that the error is a maximum for altitudes in the region of 45; it seems to me that the conclusion is incorrect. I have no quarrel with Commander Middendorp's mathematics, but with his fundamental hypothesis, which is that when a sextant is tilted it is rotated about the line of sight to the star. I believe on the contrary that a sextant tilt is a rotation approximately around a horizontal axis.