bluuebunny/crossref_metadata_2025 huggingface dataset:
Standard Time
Authors: Palmer Winslow
Published: January 2010

The controversy over the introduction of corrections to standard time, so as to force agreement between Atomic Time and Mean Solar Time seems to have its roots in an erroneous concept of the meaning or concept of the entity we call Time. For example, the preamble to H. M. Smith's paper on ‘Time Data and Navigation’ suggests that ‘…Greenwich Time and longitude are inseparable…’ and in D. H. Sadler's paper on U.T.C. there is an odd confusion in noting that Time is a measure of the rotation of the Earth on its axis and at the same time that the rotation is not uniform.
The Operation and Navigation of Jet Airliners
Authors: Alabaster R. C.
Published: January 2010

The choice of airspeed and altitude have a far more critical effect on economy of operation throughout the flight of turbo-jet aircraft than with the piston-engined type. The method of operating piston-engined aircraft for maximum range is well known, though it is normally only used on very long stages when fuel is critical; generally constant-power or constant-airspeed cruising, which result in a small penalty of fuel or payload, are preferred. The choice of operating height is also fairly wide within certain obvious limits. With jet aircraft, however, airspeed and operating height become critical and variations from economic operation reduce the payload or range considerably. The preparation of the flight plan, involving the choice of cruising altitude and speed, therefore becomes of major importance to the jet operator and navigator. The guidance of the aircraft's flight path in the vertical plane, in other words, takes on a new significance and affects the navigator's task both in planning and in flight.
The Finnish Compass Card
Authors: May W. E.
Published: January 2010

During the last half-century authors who have had occasion to write about the history of the magnetic compass have quoted extensively from The Intellectual Rise in Electricity, by Park Benjamin (New York, 1895). The wealth of references given by this writer to substantiate his statements promises a reliability which is at times sadly lacking. In one part of this book the statement is made that: ‘A single Finnish Compass has been discovered for which the people claim great antiquity, the card or scale of which is marked for a latitude where the sunrise and sunset at the summer and winter solstices differ by sixty degrees.’ For this the author gives as authority Nouvelles Annales des Voyages, Vol. xvii, page 414 (Paris, 1823), but in fact this reference contains no suggestion of the discovery of an ancient Finnish compass. All there is, is a brief reference to the ancient Finnish method of dividing the compass card which, instead of four cardinal points, had six, spaced sixty degrees apart. This information was said to be based on an article in a monthly miscellany, published in Finland under the name of Mnemosyne. Captain D. Daragan of Helsinki has been kind enough to obtain for me a copy of the original article, which was printed in Swedish, and Rektor S. Nydell has been so good as to translate it into English.
A Variable Fuel Reserve Policy
Authors: Vivian J.
Published: January 2010

More research into fuel reserve policy needs to be done if airlines are to achieve the finest balance between payload and safety. Progress is required in the accuracy of weather forecasting, in streamlining the techniques associated with the choice of required fuel reserves, and in research into the greater benefits that could be derived from well-developed operational control policies, exploiting to the full the enormous potentialities of a system-wide communications network. Captain Moline has suggested some of the inadequacies of present-day techniques.
The Discovery of an Early Bearing-Dial
Authors: Sølver Carl V.
Published: January 2010

It has hitherto been generally presumed that the division of the horizon into thirty-two points was a development of the late medieval period. Such a division, it has been said, was impossible in the pre-compass era. ‘It is questionable whether even so many as sixteen directions could have been picked out and followed at sea so long as Sun and star, however intimately known, were the only guides’, one eminent authority has declared; ‘Even the sailors in the north-western waters had only four names until a comparatively late date.’ Chaucer's reference in his Treatise on the Astrolabe to the thirty-two ‘partiez’ of the ‘orisonte’ has for long been quoted as the earliest evidence on the subject. The Konungs Skuggsjà, a thirteenth-century Norwegian work, however, refers to the Sun revolving through eight œttir; and the fourteenthcentury Icelandic Rímbegla talks of sixteen points or directions. An important discovery by the distinguished Danish archaeologist, Dr. C. L. Vebæk, in the summer of 1951, brings a new light to the whole problem and makes the earlier held view scarcely tenable. Vebæk was then working on the site of the Benedictine nunnery (mentioned by Îvar Bárdarson in the mid-fourteenth century) which stands on the site of a still older Norse homestead on the Siglufjörd, in southern Greenland. Buried in a heap of rubbish under the floor in one of the living-rooms, together with a number of broken tools of wood and iron (some of them with the owner's name inscribed on them in runes) was a remarkable fragment of carved oak which evidently once formed part of a bearingdial. This was a damaged oaken disk which, according to the archaeologists, dates back to about the year 1200.
Methods of Conducting Ships’ Speed Trials
Authors: Verstelle J. Th.
Published: January 2010

The usual method of conducting ships’ speed trials is for the ship to make runs over a measured mile. Recently, however, sea trials have been carried out using other methods, which seem to offer certain advantages. The trials of the S.S. United States, for example, were carried out using Raydist and Decca was used in the speed trials of S.S. Manchester Spinner off the Isle of Man. This paper discusses various methods of determining the ship's speed, the diameter of the turning circle and other data normally measured during sea trials, and makes an assessment of their relative convenience and accuracy.
The Navigator in Antiquity
Authors: Taylor E. G. R.
Published: January 2010

The problem of navigation, reduced to its very simplest terms, is how to get from X to Y. But this statement appears at first sight to require the proviso ‘given the means of transport available’, whether camel, ship, plane or rocket. Each sets up its special limitations to free movement, but in effect merely determines that XY must be broken up into segments, X Y1, Y1 Y2 and so on. Further reflection would probably add two additional considerations, the navigator must get safely and expeditiously from X to Y. But this again can only break down the route into fresh segments whereby dangers and difficulties are avoided. It is still for the navigator just the problem of getting from X, where he is, to a designated Y, where he wishes to be.
The Development of Shipborne Navigational Radar
Authors: Hansford R. F.
Published: January 2010

A Brief introduction on the purpose of the paper constitutes Part 1.

Part 2 of the paper traces' the historical development of navigational radar in the United Kingdom from the beginning of the late war to the present day. The use that was made of the very early radars is mentioned and the improvement brought about by the introduction of the PPI and centimetre radar is described. An account is given of how radar assisted the Normandy landings, of the techniques employed and the lessons that were learned. It is shown how a change to shorter wavelengths improved the performance, and how this made possible a large experiment in the Scheldt Estuary designed to help convoys to reach Antwerp in fog; the navigational difficulties of this experiment are described and it is shown how an elaborate drill had to be prepared for navigating these difficult channels to allow the troubles to be overcome. The thought that was devoted to the navigational needs of the Merchant Service in peacetime is dealt with, together with the elaborate trials that were carried out in the Thames Estuary to check the plans for peacetime development. It is shown how the new equipments which were developed brought about a large improvement in performance and ease of operation. In particular, the use of new displays allowing the PPI to be superimposed on the chart is dealt with and the simplification of navigation and pilotage which this allowed; the success with which ships were navigated and piloted on radar information alone is also dealt with. Some notes are included on the work of the two first International Meetings on Radio Aids to Marine Navigation. A short account is given of some experiences with radar in Norwegian Fjords.

Part 3 describes the present position where commercial navigational radars are in production and fitted to a number of British and foreign vessels. This part compares the performance of some British and United States equipments and also compares the requirements of the British and United States Government performance specifications.

Part 4 reviews some of the problems outstanding today and makes some suggestions on possible future developments. In particular, suggestions are offered on improved PPI'S, on new systems of chart comparison, on an alternative form of display for ship-handling and, looking rather further ahead, on a new form of close range and pilotage radar.
The Navigational Work of the Nautical Almanac Office
Authors: Sadler D. H.
Published: January 2010

Almost ten years ago (14 March 1938), in this same lecture hall, the Astronomer Royal, our newly elected President, opened a discussion on the recently published Air Almanac. That meeting, held under the auspices of the Royal Geographical Society, can justly be said to mark an epoch in the application of astronomical methods to air navigation in this country; but it was remarkable in other ways too. First, it provided that opportunity for criticism, by users and by others interested, of the provision to be made for astronomical navigation in the air, which it is hoped the Institute will provide for all aids to navigation. Secondly, the preparation of the Astronomical Navigation Tables was first announced; this may not appear very remarkable in itself, but it was the first time, since the days of Nevil Maskelyne, fifth Astronomer Royal, that the Nautical Almanac Office had prepared any major tables for the reduction of navigational observations!
A Use of the Pre-Determined Position Line at Sea
Authors: Bolton R. G.
Published: January 2010

As A preliminary to the discussion of the pre-determined Position Line, it will be advantageous to consider the system of working a Position Line on the Intercept method. Although this is well-known to navigators, a certain analogy exists between the two and it may be demonstrated quite simply.
Concerning an Error in Observed Altitude
Authors: Middendorp J.
Published: January 2010

During the cruise of H.M.S. Van Kinsbergen, of the Royal Netherlands Navy, with 92 midshipmen on board (of whom 66 were Executive Branch), as may be expected, a great many sights were taken. Very often the ship's position was obtained by bearings shortly before the star observations were made; in this way the DR position was known and the accuracy of the sights could be determined.
The Sailor in the Middle Ages
Authors: Taylor E. G. R.
Published: January 2010

The sailor will not be kept from the sea, even though empires fall and foreign invaders multiply. Yet we cannot expect to hear much of him in such troubled times. We know, however, that although European ships no longer sailed to India, yet, after the barbarian destruction of the Roman Empire, overseas trade did revive, and the foundations of such famous maritime states as Venice were laid. We know, too, that although the Arabs overran the whole length of the Mediterranean Sea, they were pushed back out of the islands by sea-borne expeditions from Italy and Catalan Spain, while when the Holy Places in Palestine were captured by the Turks (who were not ‘gentlemen’ like the Arabs), there were ships and sailors ready and able to carry crusading armies to the East, and to provision them while they were there.
Radar and the Weather
Authors: Satow P. G.
Published: January 2010

The paper is divided into two parts.

Part 1, under the heading of Non-standard Propagation, concerns variations in the apparent performance of marine navigational radar in its use for detecting shipping and land targets. The effects of changes in the density of the lower layers of the atmosphere on radar transmissions, their distortion of radar coverage for better or for worse, and resultant errors in the evaluation of echoes are here examined.

Part 2 describes the way in which weather echoes may influence and restrict radar-assisted navigation. The attenuation of field strength with various types and intensities of precipitation, and the effects of these factors on the navigational and collision-warning uses of radar are examined. The detection, tracking, and application of weather echoes as an aid to short-range weather forecasting are also covered.
The Range and Accuracy of Consol
Authors: Jessell A. H.
Published: January 2010

The basic principles of Consol have been explained in a previous article; the factors affecting the range and accuracy of the system are here discussed. A summary is given of the results obtained practice, and the article concludes with a brief discussion of developments which will lead to improved performance.
Significant Figures
Authors: Burton S. M.
Published: January 2010

For many years past great efforts have been made to devise methods of obviating the necessity for making navigational calculations by logarithms, on the grounds that the logarithmic process is too slow for modern navigational purposes. For some such purposes it undoubtedly is; but all these short methods suffer from some disadvantage or other, and when the preliminaries (which generally involve calculating the hour angle) common to both are completed, the difference in time between completing the sight by inspection and interpolation, and by logarithms, is not so great. For this reason it seems possible that logarithms would still be considered preferable for a wider range of purposes than at present, were it not that most of the volumes of logarithms still commonly used for navigation are designed for more accurate calculations than are necessary or justifiable for the practice of navigation, and hence are unnecessarily cumbrous and slow in use.
The Genesis of the E.A.N.T.s
Authors: Anderson E. W. , Sadler D. H.
Published: January 2010

During 1943 there was produced, for trial purposes, a limited edition of the so-called Experimental Astronomical Navigation Tables (E.A.N.T.s). For various reasons these tables were not adopted for general service use in the Royal Air Force, and copies are no longer available. The tables possess some points of interest, which are described below for the first time.
The Deep Scattering Layer
Authors: Ritchie G. S.
Published: January 2010

At depths of, generally, between 20 and 250 fathoms in the oceans, sonic and ultrasonic transmissions are frequently scattered by a layer which can be detected on the echo sounding trace, sometimes so strongly as to suggest a sea-bed echo. The cause of this layer, of which the depth has been observed to rise at sunset and sink at sunrise, is not precisely known, though it is generally thought to be biological. Investigations into the deep scattering layer (DSL), as it is called, are being conducted in many countries, principally in the United States, France and Great Britain, and a recent paper by Tchernia has set out the present state of knowledge on the subject.
Margetts's Horary Tables
Authors: Sadler D. H.
Published: January 2010

IN the course of a systematic search for tables or graphs using the principles appealed to in the Experimental Astronomical Navigation Tables (see p. 333), I examined a copy of the above tables, whose full title follows:

‘Margetts's Horary Tables for shewing by Inspection the Apparent Diurnal Motion of the Sun, Moon and Stars, the Latitude of a Ship and the Azimuth, Time or Altitude corresponding with any Celestial Object.

‘London. Printed for and sold by the Author. “Published as the Act directs 1st July 1790.”’

These tables (or diagrams) do not appear to be well known and they seem to possess sufficient interest to warrant notice. The author's own description is so precise that I can do no better than to repeat it verbatim with a few added notes of explanation. The accompanying photograph, reproduced from the copy in the collection of navigational books and tables in the Admiralty Library by kind permission of the Admiralty Archivist, shows a typical opening of the tables.

I have been unable, in the course of an admittedly hurried and incomplete search, to find any biographical information about Margetts. Perhaps some reader of the Journal can supply the deficiency.
The Barcoo Observations
Authors: Parker J. B. , Sadler D. H.
Published: January 2010

In the course of a survey of the Arafura Sea by H.M.A.S. Barcoo, many astronomical observations were made under good, and controlled, conditions; through the courtesy of the Admiralty these observations have been made available for analysis. This analysis has been regarded as a pilot investigation for the working party on the accuracy of astronomical observations at sea. Its main, crude, result gives (from these observations) a standard deviation of a single observation as 1.1.

During the latter half of 1952, H.M.A.S Barcoo was engaged in surveying an area, 200 miles by 30, in the Arafura Sea some 50 miles north-west of Cape Wessel. Seven fleets of beacons were laid out, each consisting of about 14 beacons at intervals of about 5 miles. The first beacon of each fleet was used as a datum beacon and its position determined by astronomical observations by three observers, both morning and evening on two days; each observer took as many stars as possible on each occasion and the mean of three or four shots of each star. The datum beacons were connected by taut-wire runs and it was found that the taut-wire distances were not in agreement with the mean positions determined from the astronomical observations. It was primarily for this reason that the observations were carefully collated by Lieutenant J. M. Child, R.N., and forwarded to the Admiralty. The observations were in due course sent to H.M. Nautical Almanac Office, where it was decided to subject them to a detailed statistical analysis. They are not suitable for inclusion in the (deliberately) heterogeneous observations being collected for the working party of the Institute on the accuracy of astronomical observations at sea; but they provide the ideal material for a pilot investigation into methods of analysis.
The National Maritime Museum
Authors: May W. E.
Published: January 2010

When the Society for Nautical Research was founded in 1910, one of its objects was to work for the foundation of a National Maritime Museum. To many this must have seemed an unattainable star on which to focus their hopes, especially when a few years later the First World War broke out. However, fortune changed, and in 1928 the great Macpherson Collection of maritime prints and drawings came on the market. A fund was started to purchase it for the nation, but Sir James Caird, a wealthy shipowner, stepped in and bought the entire collection. Matters now really began to move. The Admiralty was anxious for more space in the Royal Naval College at Greenwich and this could only be obtained by removing the Royal Naval Museum, which had been transferred from Somerset House, and the Greenwich Hospital collection of paintings, which had been started in the Painted Hall in 1824. A new home was needed for these and for the Macpherson Collection, and then in 1933 the Greenwich Hospital School was moved to Holbrook, and the great range of buildings just across the road from the Royal Naval College became available. In the next year the National Maritime Museum was established by Act of Parliament and the conversion of the buildings was begun; but already fresh acquisitions had begun to come in. Sir James Caird bought such treasures as came on the market and, capably advised by the distinguished naval historian, Sir Geoffrey Callender, who was to become the first director of the museum, laid the foundations of a collection which has become the envy and admiration of maritime nations.
The Bathyscaphe's Record Descent
Authors: Houot G. S. , Willm P.
Published: January 2010

The following is a summary of a lecture given to the Institute, in the Science Museum's lecture theatre, on 5 May 1954. Dr. G. E. R. Deacon, F.R.S., Director of the National Institute of Oceanography, was in the chair. The lecture was illustrated by slides and a film.

Alexander the Great was probably the first deep-sea diver. He is supposed to have had a glass boat made and to have spent some ninety days under the water observing strange and rare animals which, it may be conjectured, were no more than mythological. Since that time a number of attempts at producing diving spheres were made, but apparently without success until in 1832 a Spaniard made one of wood, which he went down in, and, unfortunately, never came up. In 1892 a steel sphere was made by an Italian, Balzamello, who reached a depth of 165 metres. The next developments were those of the Americans Beebe and Barton, much later, in 1930–34. They dived to 908 metres in a sphere attached to its parent ship by cable. Later on Barton by himself achieved 1380 metres.
Vice-Admiral Radler de Aquino
Authors: Sadler D. H.
Published: January 2010

Francisco Radler de Aquino, one of the first of the Institute's few Honorary Members, died on 8 October 1953 in his seventy-fifth year, but his death was not officially notified to the Institute for some months. He had been in failing health for some years, but had made sufficient recovery from a serious illness to prepare, and practically see through the press, still another volume of tables. He had retired from the Brazilian Navy in 1935 at the age of 57 with the rank of Captain; and it was not until sixteen years later, on 24 March 1951, that he was given the belated promotion to Vice-Admiral: the reasons for the delay were obscure but apparently political. By his death the science of navigation will lose one of its most stalwart champions and one of its most prolific writers. The field of tables for astronomical navigation will hardly seem the same without his colourful personality and his constant additions to his many publications. Many, including those who did not always agree with his views, will miss him as a friend, even though that friendship had largely been carried on by correspondence.
PPI Pictures on Charts
Authors: Day Archibald
Published: January 2010

In the discussion following the papers read on ‘Methods of Air and Surface Navigation’ at the Institute meeting on 15 January 1954 (see pages 159–164 of the Journal, Vol. VII, No. 2, April 1954), the question was again ventilated of including PPI pictures in the Admiralty Pilots or Sailing Directions.
Accuracy Contour Maps of a Ship's Position
Authors: Sameshima N.
Published: January 2010

The writer has drawn the accuracy contour maps of a ship's position fixed by cross bearing, horizontal sextant angle method and Loran aid. The accuracy of the fixes has been evaluated in terms of the probability density.
Radar and Collision at Sea
Authors: Clissold P. C. H.
Published: January 2010

Captain G. C. Forrest's letter (this Journal, Vol. VII, p. 203) raises some interesting points well worth discussion:

‘(1) That radar-using ships, taking broad evasive action, shall alter course to starboard only, and not at all once they are within five miles of the other vessel, though they may reduce speed or stop.’
A Fix by Total Solar Eclipse
Authors: Sadler D. H.
Published: January 2010

A total eclipse of the Sun provides an opportunity, rare though it may be, of obtaining an instantaneous fix from the Sun alone. Eclipses vary greatly in character, in position on the Earth, in the width of the path of totality, in the duration, and also in the direction of the path. However, the shadow of the Moon cast by the Sun is always a right circular cone which, in the case of a total eclipse, intersects the Earth's surface at some point before its vertex. Owing to the motion of the Moon in its orbit round the Earth the shadow moves at a speed of about 2000 m.p.h. from west to east (it varies considerably according to the distance of the Moon from the Earth).
The Speed and Size of Ships as Factors in Collisions
Authors: Oudet L.
Published: January 2010

There are endless regulations concerning the speed and size of vehicles on our roads, but none that apply to vessels using our maritime routes, even though there is a regular increase, in step with technical advances, in both the size and speed of ships. For reasons of economy roads are narrow, and the necessity to avoid obstacles means that they have to be winding. No such considerations apply at sea; changes of direction are slight and widely spaced out, nor are there any ditches or hedges to limit the width of the routes that are used. Nevertheless, studies of maritime traffic have shown that overcrowding is becoming more and more pronounced on the busiest routes, and the present tendency to develop oneway routes is an implicit recognition of the fact that the remedies for such overcrowding on the roads and at sea have something in common. One-way traffic, for example, is derived from the Collision Regulations (Rule 25). It is worth examining what help the Regulations can give in solving problems raised by the size and speed of ships.
Doppler Velocity Measurements of Ships
Authors: Lizoń Andrzej
Published: January 2010

A basic parameter of a ship's motion is its velocity, a knowledge of which is important to both seaman and ship designer. Often it is sufficient to know the ship's mean speed at given engine revolutions. Sometimes the knowledge of its instantaneous velocity may also be required.

Instantaneous velocity measurement is possible by means of a doppler radar. The radar is located on the ship and at a selected point of reference on shore, or on a buoy, a reflector is placed which strongly reflects the electromagnetic waves; the ship is then steered directly towards or away from the reflector. The radar emits a beam of electromagnetic waves directed toward the reflector. Due to the ship's motion in relation to the reflector, the received signal returned by the reflector is shifted in frequency from the transmitted frequency by a doppler frequency. This frequency is proportional to the instantaneous velocity. The mean velocity may be measured by counting the number of signal periods of doppler frequency. This number is the measure of the distance covered by the ship. Simultaneous measurement of the time enables the mean velocity over the given distance to be determined.

This method makes possible the measurement of the instantaneous velocity and acceleration of the ship. Simultaneous observation of instantaneous velocity when measuring the mean velocity allows a measuring length along which the velocity of the ship reaches a steady value to be chosen and the maximum velocity to be measured.
The Significance of Marshallese Stick Charts
Authors: Playdon George W.
Published: January 2010

The stick charts found in the Marshall Islands, of which some 20 or 30 are extant in museums throughout the world, have for long puzzled historians of navigation. In this paper, which is based on a more complete work, to be published elsewhere, the author examines the authenticity and meaning of these objects and concludes that they were mnemonic devices, of no great antiquity, to facilitate navigation and to train navigators.
An Analytic Measure for the Difficulty of Human Control
Authors: Hollister Walter M.
Published: January 2010

An important consideration in the design of systems for human control is the difficulty of the task. An analytic measure of this subjective consideration is denned. The difficulty is a function of the lead factor which is an integrated measure of the amount of lead the human must produce. The theory together with experimental results imply that the performance function minimized by a human controller includes the amount of control as well as the amount of error. The difficulty is constrained by the capability, training and stress level of the operator. Remnant is accounted for by assuming that the operator generates additive noise as a function of the difficulty. The model is used to explain Bernotat's experimental results with prediction display.

This work was performed while the author was a guest professor at the Institut für Flugführung as part of the exchange programme between M.I.T. and the Technische Universität, Berlin.
S.S.T. Simulation Exercises
Authors: Schmid H.
Published: January 2010

The S.S.T. simulation programme of the F.A.A., already in progress since May 1963, aims at determining system requirements both ground and air in the period 1970–75 and, as a future project, in the era 1975–80. In this context, air operations involving the following types of aircraft are under study:

(a) Current and future military aircraft with supersonic speed capabilities;

(b) Concorde-type operations;

(c) Mach 3 or mach 2.7 civil transport operations.

Since the start of the S.S.T. simulation programme, six studies have been undertaken, each of an average duration of 6 months.

From May 1964, a S.S.T. flight deck simulator (modified DC-8 simulator), located at the N.A.S.A. Research Center, was linked with the A.T.C. simulator at N.A.F.E.C., for communication of positional data (digital, including S.S.R.) and voice information, and thus formed part of the traffic sample under study, i.e. one aircraft among 108 others that can simultaneously be simulated at N.A.F.E.C.

Whilst previous exercises concentrated on terminal area (T.M.A.) requirements, the exercises in progress in July 1966 were designed to examine extended T.M.A. and en-route operations in the early 1970s, with Concorde and mach 3 or mach 2.7-type S.S.T.s flying in or through a mixed environment of subsonic traffic. Amongst other parameters, a variety of geographical zones, air traffic control centres, T.M.A. control units, route network configurations in the New York, Boston, Cleveland and California areas, were simulated with a view to determining the impact of specific regional terrain and traffic conditions.
British Mathematical Biobibliography
Authors: Wallis P. J.
Published: January 2010

Thepublication of a new impression of Professor E. G. R. Taylor's first volume ofMathematical Practionersso soon after the appearance of her second volume makes it a particularly appropriate time to take stock and consider the next steps. Despite various criticisms, some of which will be discussed below, all reviewers agree that her volumes mark a great advance in this field and will be of ‘immense service to scholars’. Our debt to the author is all the greater when we realize that these books followed on a whole series of standard works in her own subject of geography, and that she was neither a mathematician nor a bibliographer. The best tribute to Professor Taylor is to continue the work recorded in these two volumes, but there are few who have the detailed knowledge and expertise to follow her in such a wide field. This article will, for example, offer little comment on instrument-makers who form such a large section of herpractitionersand who left records of their work in museums and private hands all over the country; here we shall be much more concerned with the written work, with the bibliography of the subject.

Reviewers of her volumes have found it difficult to define the practitioners of whom she wrote and to decide in what sense they differ from mathematicians in the normally accepted sense of this country or overseas.
I—Doppler Navigation in S.A.S.
Authors: Pedersen Einar S.
Published: January 2010

In order to find out what type of doppler navigation equipment would be most suitable for the S.A.S. fleet of DC-8s it was decided to start a programme of doppler evaluation in Spring 1958. The doppler evaluation programme included evaluation of doppler equipment from Canadian Marconi, General Precision Laboratory (G.P.L.) and Collins Radio Company.

The programme started in April 1958 with evaluation of Canadian Marconi doppler equipment. The evaluation period lasted six months. In April 1959 evaluation of Collins and G.P.L. doppler equipment started and lasted for eight months. In March 1960 evaluation of Collins and Canadian Marconi doppler equipment started and is still in progress. And finally by the middle of May 1960 evaluation of G.P.L. Radan 500 was in progress.
II—An Evaluation of the Marconi AD 2300
Authors: Brunt W. E.
Published: January 2010

When, in 1958, B.O.A.C. undertook to evaluate the Marconi AD 2300 doppler navigator, the exercise was planned with great care. The aim was to determine the performance of the system in quantitative terms, and to express the results so that their operational significance was clear.

In preparing this evaluation, three objectives were stated, as follows:

(a) To obtain quantitative data on the performance of the AD 2300, considered as a measuring device, in terms of accuracy, consistency and reliability.

(b) To obtain qualitative information on the optimum methods of system application, by reference to observer reaction.

(c) To introduce the doppler system in operation to a wider selection of B.O.A.C. flying staff, in order to develop a body of informed opinion.

It is the first of these objectives with which this paper will deal.
II—Traffic in the Dover Strait
Authors: Poll J.
Published: January 2010

If we examine the traffic in the Strait of Dover, which in its most narrow part is 17 miles wide, we notice that nearly the whole of this traffic, about 98 per cent, is concentrated and strangled under the British coast, in a narrow pass about five miles wide. Very heavy traffic coming from all parts of the world gathers together in the bottleneck which is the Channel. Thus innumerable vessels, when still in the Strait of Dover, spread out fan-wise at the very place where traffic in an opposite direction concentrates in order to make the same narrow passage. It is the unorganized convergence of these many routes which concentrates this very dense traffic at the mouth of the Strait of Dover and is the cause of all too many collisions. One immediately concludes that by relieving congestion and by organizing or canalizing the traffic, the problem will have received an acceptable answer.
Determination of Position on the Earth from a Single Visual Observation of an Artificial Satellite
Authors: Scott W. A.
Published: January 2010

While engaged in the observation and prediction of the position of Sputnik I, it was realized that, if a reliable orbit were available, and an observation of the satellite against the background of stars were made to a precision of about 0°·1 and timed to about 0·2 of a second, then the position of the observer could be determined to a precision sufficient for most navigational purposes. The following account demonstrates how this has actually been done from a single visual observation of the American Balloon Satellite Echo I (designated 1960ι1).

Principle of method. The direction in which an observer on the Earth's surface sees an artificial satellite at any instant differs from that in which it is seen by any other observer and from that in which it would be observed from the centre of the Earth. The amount and direction of the parallactic shift can be determined from the comparison of the direction of observation with that calculated from the geocentric ephemeris of the satellite; and the position of the observer on the Earth's surface can be uniquely calculated from this parallactic shift. Only a single observation is required, without reference to the vertical.
A Further Note on Seaborne Traffic
Authors: Oudet L.
Published: January 2010

The Channel Bridge. I am happy to report that Commandant Poll's admirable scheme for traffic in the Strait of Dover (p. 75) has provoked, at least on paper, a most interesting reaction. Commandant Poll brought out his plan in February 1960. In March the Compagnie Française d'Entreprises consulted me about a scheme for a Channel Bridge which they had drawn up in conjunction with the English firm of Dorman Long and the American Merrit-Chapman and Scott Company.

As seamen we hold no brief either for a bridge or for a tunnel; our personal interest can be no more than an expression of our attitude as citizens of our respective countries. But as soon as the matter was brought to my attention I realized that there can be no two opinions about our professional attitude: we must first make sure that the bridge will neither endanger nor delay shipping, and when we are satisfied on that point, we must do nothing to hinder the realization of a project which cannot fail to improve international relations in our ageing West.

How are we to make sure of our necessary condition? The first and most important step is to establish the one-way routes detailed by Commandant Poll, and to see to it that the arches which cross them are as wide as possible. The normal span, 200 metres from pier to pier, with a clearance of 53 metres, is suitable only for small ships.
III.—Ergonomics in Ship Design
Authors: Wilkinson G. R.
Published: January 2010

Ergonomics can mean the science of making work fit the worker or the study of man at work. This paper will be confined to the aspects of ergonomics affecting ship design, which include anatomy and physiology, anthropometry, and physiological and experimental psychology.
IV.—The Influence of Technology on Navigation as an Occupation
Authors: Hatfield M. R. , Smith M. H.
Published: January 2010

This paper falls roughly into three sections: the inter-relationship between economic forces, technological change and occupations, a brief history of navigation in occupational terms, and the present and future state of the occupation. The conclusions drawn may be open to discussion, since it presents a point of view and not a specific piece of research. It is restricted to the occupation of navigation in the Merchant Navy; naval and aircraft navigation appear to be very different as occupations.
Automatic Control of Large Ships in Pilotage and Berthing
Authors: Dove M. J.
Published: January 2010

This paper surveys the present methods of pilotage and berthing, discusses some of the statistics of collision and grounding in confined waters, and suggests the development of shipborne automatic control devices to be used for the pilotage and berthing of large vessels. The proposed system, with its associated shore-based equipment, would carry out a similar function to the automatic landing devices fitted in aircraft, and would be part of an overall marine traffic control system. This system would enable large ships to be berthed automatically in reduced visibility and improve the safety of the movement of large ships in congested waters. The author lectures in the Department of Marine Electronics at Southampton College of Technology.
Further Comments on the 1972 Collision Regulations
Authors: Wylie F. J. , Professor Hugon
Published: January 2010

Captain Wylie's extensive and detailed criticisms of the Sailing and Steering Rules in the new Collision Regulations (Journal, 26, 365) were published in the January number of Navigation, the journal of the French Institute of Navigation, with an editorial note by Professor Hugon. The note and Captain Wyile's reply are given below.
Sines, Versines and Haversines in Nautical Astronomy
Authors: Cotter Charles H.
Published: January 2010

Of immense importance to nautical astronomers are tables of trigonometrical functions. The history of these begins with the table of chords first suggested by Hipparchus two centuries before the beginning of the Christian Era. The earliest table of chords extant is that computed by Ptolemy (fl. c. 150 a.d.) whose table, true to the sexagesimal tradition, is based on the division of the radius of a circle into sixty parts. The first table of half-chords, or sines, is supposed to be of Indian origin and to date from the sixth century; but credit for being first to use a table of half-chords for solving spherical triangles belongs to the Arab mathematician Albategnius who flourished during the tenth century. The first printed table of sines, according to De Morgan, is a small work giving sines to each minute of arc from 0° to 90°, undated and unsigned but evidently published before 1500.
Aircraft Navigation by Satellite
Authors: Myers H. A.
Published: January 2010

Aircraft navigation using doppler and orbital information transmitted from a satellite is shown to be feasible, at least in a limited sense, using the least squares, differential correction method of computation. If sufficiently accurate velocity information can be provided, this approach could yield positions for long-range aircraft that are an order of magnitude more accurate than have been achieved with other world-wide, all-weather, all-altitude systems, such as doppler and inertial navigators.

The least squares, differential corrections solutions for both position and velocity do not converge for reasonable initial errors. Therefore, accurate aircraft velocity components, such as those provided by a doppler navigator, must be known. For one-knot velocity errors the position of a 500-knot aircraft can be determined to one-half nautical mile or better for latitudes up to 70 degrees. Several-knot velocity uncertainties result in position errors of a few nautical miles.

The position accuracies for supersonic aircraft are limited by the velocity accuracies achievable with the best doppler navigators. Computational methods that yield velocity as well as position, so that the satellite system would not have to depend so much on another navigation aid, would be most desirable.
II—The Use of an Airborne Digital Computer in a Compound Navigation System
Authors: Pearson M. G.
Published: January 2010

The previous paper described how the two components of a compound system could be combined, through the medium of a pictorial display, in a common coordinate system. This essential process can be carried out by an airborne digital computer with considerable advantage, and with a degree of refinement—e.g. data smoothing— which would be beyond the scope of the simpler manually-operated system. In other words, the computer can introduce a second mode of compound operation which differs from the simple relationship between position-fixing and D.R. systems described earlier, in that by continuously combining the incoming information from the position-fixing system and the dead-reckoning device it can deliver an output of a substantially higher quality than that of either input taken separately.
Improved Manœuvrability and Ship Efficiency
Authors: McMullen Colin
Published: January 2010

In the days of sail a merchantman's success as a trader was governed by the seamanship of her master and the sailing qualities of the ship. A vessel which could turn easily to windward in difficult conditions could sometimes manœuvre under sail, in and out of port, without assistance while her more ungainly sister was dependent upon warping, kedging and towage by craft under oars. More important still, when on passage the efficient sailing ship could get herself out of trouble if she found herself in a tight corner on a lee shore in a gale of wind.
The Mathematics of Collision Avoidance in Two Dimensions
Authors: Hollingdale S. H.
Published: January 2010

The geometry of collision at sea has been dealt with in a series of papers published in the Journal, notably by Sadler (10, 306), Calvert (13, 127), Garcia-Frias (13, 316) and Morell (14, 163); and a further contribution from Calvert (to which reference is made in this paper) will be published in the next number.

The object of the present paper is to examine whether anti-collision manœuvres, here considered for the case of two craft moving in a plane, can be formulated on a rigorous logical basis. If they can, then clearly a proper appreciation of the geometry of collision is a prerequisite to the formulation of any rules and regulations. In this important paper the author gives a precise and complete answer to the basic problem, and he proves mathematically that it is the only answer. As Dr. Hollingdale freely acknowledges, however, this can only be a contribution to the study of the collision problem, which involves innumerable operational factors in addition to the geometry of the situation.

The convention adopted in the present paper is that each craft shall manœuvre so that if the other craft stands on, the sight line always rotates in the anti-clockwise direction. The analysis shows that a simple set of manœuvres can in fact be developed on this basis and that such manœuvres are the only ones that, geometrically, meet all the specified requirements. In all cases the combined manœuvre converts a collision situation into a ‘miss’ of at least a specified magnitude.
The Long-term Plan for Air Traffic Control
Authors: Hunt V. A. M.
Published: January 2010

This paper by the Director of Control and Navigation at the Ministry of Aviation, reviews the present state of planning for air traffic control in the United Kingdom. It indicates that whilst progress is evolutionary and continuous, big steps take place approximately every ten years. The author concentrates on four principal facets of air traffic control which cause the most acute problems, namely the medium-haul operations in densely populated areas; the terminal problem; long-distance operations over the Atlantic; and low-level, short routes in the south-east of England.

The paper outlines the basic air traffic control system of the future and indicates the ways that data processing and radar may be used. It makes a short reference to the specific problems of the supersonic aircraft and concludes by referring to two principal experimental projects now in hand to enhance our knowledge of data processing with respect to air traffic control.
The Planning of Runway Layouts as Affected by Weather
Authors: Jacobs L.
Published: January 2010

A method is presented for quick calculation of the frequency of cross-wind components which limit the landing of aircraft on runway layouts at aerodromes ánd for deriving the best runway layouts for a site with a known or deducible wind distribution. The method depends on some initial study of the relevant wind rose but an exact solution is obtained by the application of the empirically derived formula nv = Ce–bv2 where nv denotes the percentage of time that a wind exceeds a velocity v and C and b are constants for a given site. This formula was originally verified only for the British Isles but later it has been found to be valid elsewhere where there is a wide range of wind speeds. Allowance can be made in the calculations for bad weather, e.g. dense smoke or low cloud approaching the aerodrome from certain directions, for use of one end only of a runway and for a permissible tail wind component.

The paper was originally issued in 1944. The method described has not been changed and the description is only slightly modified. The chief changes are the substitution of numerical integration using Meteor computer instead of the original planimeter measurement of curves and the introduction of the ‘bisector’ correction. Certain details of the calculation notably four-figure tables of L(i) (eqn (5)) and of the bisector correction, a complete example of the method, the way to remove ‘bias’ in wind summaries and the derivation of the bisector correction are given in a duplicated Addendum to this paper which is available on request from the Institute.