This year the Royal Society celebrates the third centenary of its foundation. In this paper Sir Harold Spencer Jones, the late Astronomer Royal, who was the Institute's first President, describes the early years of the Society and shows how closely some of its work was related to navigation.

For some two thousand years, until well into the seventeenth century, the writings of the ancient Greek philosophers, and in particular those of Aristotle, were regarded as the supreme fountain of wisdom and the source of all knowledge. The break with the Aristotelian dogma may be said to have started with the publication by Copernicus in 1543 of his De Revolutionibus Orbium Coelestium whereby the Earth was displaced from proud position as the centre of the Universe, fixed and immovable, and asserted to be not only rotating around an axis but also to be merely one of a system of planets revolving around the Sun as a centre. Copernicus had refrained for thirty years from publishing his theory as he knew that it would be received with ridicule, not merely because it was not in accordance with Aristotelian dogma but also because it would be held to be against the Scriptures. The Copernican theory met, in fact, with widespread opposition and more than a century elapsed before it came to be generally accepted; for long it was regarded as merely a convenient mathematical representation of the motions of the planets without any true physical basis.

The expansion of air traffic in the United States continues at a forceful rate and shows no signs of decelleration. The Federal Aviation Agency (F.A.A.) traffic control statistics of Fig. 1 show total yearly operations and their relative growth. The graphs distinguish between the three major airspace users, i.e. the scheduled air carriers, the military activity at F.A.A. controlled airfields, and general aviation. The term ‘general aviation’ combines all non-military and non-scheduled airline operators, such as business fliers and private individuals who operate their own airplanes. In addition to the total trend the most significant aspect to note is the high percentage of general aviation activity and its explosive growth rate.

This account of the recent International Conference on Safety of Life at Sea, has been written for the Journal jointly by Captain J. H. Quick, C.B.E., the Professional Officer and Chief Nautical Surveyor to the Ministry of Transport, who was a delegate to the conference, and Captain F. J. Wylie, R.N., the Director ofthe Radio Advisory Service of the Chamber of Shipping and Liverpool Steam Ship Owners' Association, who was an advisor to the British delegation. The account concentrates on those parts of the conference's work which will be of most interest to the seafarer, and in particular on the revision of the International Regulations for Preventing Collisions at Sea.

The Final Act of the conference, with Annexes, including the texts of the revised International Convention for the Safety of Life at Sea and revised International Collision Regulations, will be published shortly by the International Maritime Consultative Organization, from Chancery House, London.

The International Conference on the Safety of Life at Sea (1960) concluded on the 17th June. Forty-five governments had sent delegations and in addition ten other governments were represented by observers. The purpose of the conference was to revise the International Convention for the Safety of Life at Sea (1948) and the International Collision Regulations.

This account of the problems of navigating the Hustler, the Convair B-j8 supersonic bomber, was presented at the sixteenth Annual General Meeting of the American Institute of Navigation, held at the United States Air Force Academy in Colorado Springs on 16, 17, 18 June. It is published with the kind permission of that Institute.

In navigating high-performance vehicles with the precision required to get acceptable results, the individual is limited in his ability to assess all the data available about heading, speed, instrument readings, &c, and to act upon this information in sufficient time to get the job done. The same limitations apply to pilots when flight conditions approach the design limits of the aircraft. For these reasons the manual tasks required of the crew of the B-58 have been automated to the extent that transition to a missile environment seems almost complete.

In this paper, by the Director of the Radio Advisory Service, a comprehensive survey i s made of all the main trends of development in commercial marine radar since it first went to sea in 1946. The opinions of a representative group of seamen on the value they get from radar is analysed, and finally some views of manufacturers and seamen on what the future may hold are examined. The paper was presented at the annual meeting of the Ausschuss fur Funkortung held in Kiel on 10, 11, 12 September 1960, and is reproduced with the kind permission of that body.

The last fifteen years represent almost exactly the whole life of commercial radar in merchant ships; in the United Kingdom the first commercial types were beginning to go to sea towards the end of 1946. The period has been an intensely interesting one from almost every aspect of the subject and the writer is fortunate in having been associated with merchant ships, and their owners, for thirteen of these fifteen years and with the subject of radar at sea since 1936.

The doppler track computer is a navigation device which accepts inputs of ground-speed and track from a doppler radar, and computes and displays miles to go and miles transverse to a selected track. Several types are available on the market.

The heading input to the doppler may be from a magnetically slaved gyro or from a free gyro corrected for Earth rate. Thus, either magnetic tracks or gyro tracks are fed to the computer. Also, navigation may be carried out with reference to airways, mercator, conformal conic, oblique mercator, or polar stereographic charts.

In the development of instrument systems for the purpose of flight control, traditional designs have consistently failed to solve three particular operational problems:

• (a) The difficulty of transition from instrument to visual flight conditions at the final stages of an instrument approach to land in bad weather.

• (b) The preservation of instrument control when the pilot±s attention is, for any reason, directed away from the appropriate instruments. Preoccupation with other duties, lack of concentration due to fatigue, keeping a look-out for other aircraft, &c, are examples of situations when the maintenance of accurate flight control may be lost.

• (c) The effective monitoring of the accuracy and precision with which an automatic pilot is achieving its selected function. Admittedly this can be achieved by the pilot continuously watching his appropriate primary instruments, but this tends to be extremely monotonous, and to a considerable extent reduces the advantages to be derived from effective automatic control. This particular problem reaches its peak under high altitude, high-speed, conditions of cruise of a jet transport, and in the final stages of an automatic approach, automatic flare, or automatic landing, on any type of aircraft.

These methods were briefly described in the Journal (Vol. 13, No. 2). They were prefaced by some comments designed to draw a comparison between the air and sea problems and collision rates. Statistics are liable to be misleading if not perfectly understood and definitive, and marine collision statistics as much as any. It should be realized that Lloyd's List figures include almost every collision incident to ships of joo tons and over and that a comparable air figure would probably need to include damage to aircraft by aircraft on airfields and in hangars and whether under their own power or in tow.

To obtain all the available information from radar when visibility is poor, it is widely recognized that plotting is essential. No doubt plotting is carried out whenever possible, but in many merchant ships at sea today the ideal has limitations due to manning difficulties. Where the master has only one officer on the bridge to assist him it is not easy to cope with all bridge duties and carry out plotting in the usual way. To obtain full and accurate information a plotting officer must give his undivided attention to make use of the three known elements, range, bearing and own speed in order to produce the other ship's course, speed and nearest approach and follow up with the change of course and speed that may be required to keep out of the region of collision.

F. G. Smith describes (this Journal, 13, 109) a system for determining position from a single observation, probably lasting for a time of the order of a few minutes, of radio transmissions from an artificial Earth satellite. There are in this system two engineering difficulties which I think Dr. Smith has underestimated; these are the frequency stability and the power required. In order to establish these requirements it is necessary to consider in some detail how Dr. Smith's system would work.

On page 240 of the April Journal, Wing Commander Dickie pointed out that in traffic control as we know it today, it is ground-speed and not air-speed that really matters. As he says, it is not possible for the pilot to maintain a constant ground-speed and it is for this reason that I suggest the concept whereby individual aircraft maintain constant power which, in the short term, must give constant air-speed. Slight changes in power will maintain a planned traffic pattern on any one route at any one height. Individual speeds will of course be different, and overtaking will have to be arranged by divergencies of track or height.