My title is deliberately rather similar to that of Jed Williams' book because it was from his erudite and comprehensive work that I drew my inspiration. There are many volumes dealing with radio navaid engineering development but few, if any, about the very real and practical problems faced by navigators of interpreting, sometimes under very difficult circumstances, what they presented. Very few navigators of the 40s and 50s were expert draughtsman or academicians with degrees in mathematics or electronics, yet they were expected to comprehend and apply concepts that a few years earlier would have earned them such degrees. These fundamental problems of interpretation also seem to have been rather lost on some of those who were responsible for choosing which radio navaids to install. I have terminated my survey at the ‘steam’ era, rather than going all the way to ‘satellites’, not only because we have heard so much of satellites lately that it is time to give them a rest, but also because it was computers — the ‘ steam’ of navaids — that got us into the modern age of automated navaids when interpretation became far easier and the need for specialists doing little else vanished. My own experience is that of an aerial navigator so I hope our marine and land-based members will not object if I confine my remarks to aviation.

Part I of this chapter was included in the January 1997 issue of the Journal, Vol. 50, p. 65.

The Smith Brothers, 1919. Captain Ross M. Smith, of the Australian Flying Corps based in Palestine, flew a Handley Page 0/400 late in 1918 on a special flight to Baghdad and beyond, carrying as passenger Major General W. G. H. Salmond, the RAF's Middle East Commander. Flying as co-pilot was Brigadier-General Borton, Commander of the Palestine Brigade. Smith had been flying, in support of Lawrence's forces, another 0/00 which Borton had brought from England.

In the early sixteenth century, Portuguese navigators on voyages outside the tropics ran into an unexpected problem in navigating with the plane chart since the latter took no account of the convergence of the meridians. Voyages between Brazil and the Cape of Good Hope were accomplished much faster than the chart led them to forsee. To overcome this problem, were Portuguese pilots of the first half of the sixteenth century using globes to set their courses with on great circle courses? The general opinion is that they were not. Yet the mathematician Pedro Nunes (1502–78) describes in a short treatise entitled Tratado que ho Doutor Pedro Nunez fez sobre certas duvidas na navigação (published in 1537, but probably written in 1534) how the navigator Martim Afonso de Sousa, on his return from the east coast of Brazil in 1530–2, had asked him to solve several problems of navigation encountered on the voyage.

This paper is the sixth chapter of a series on the history of air navigation systems which have appeared from time to time in the pages of the Journal since 1988. Part II of this chapter will appear in the next issue of the Journal.

The author acknowledges the assistance of Bath College of Higher Education and, in particular, Dr Terence Rodgers, The Royal Aeronautical Society, The Royal Air Force Museum, and Philip Saxon of the Royal Air Force Historical Society.

I am pleased to see that, in light of my critical evaluation, Arne B. Molander has reevaluated a number of points in his analysis, and has revised his proposals of Columbus's alleged use of the Moon for determining his longitude. However, it is disappointing that these latest proposals again do not seem to have been thoroughly considered.

Since it is clear that Columbus's East–West position fixes are not correlated with visible lunar-planetary conjunctions, Mr Molander's latest hypothesis is that Columbus observed a dark-horizon moonrise or moonset near each conjunction – which usually can be done whether or not the conjunction itself is visible. However, it is entirely unclear how such an observation can be converted into a longitude. Reading attentively, we can glean a few details of this process: only a single observation is required, since some positions are computed within a few hours of the purported observation; and Columbus apparently used the Ephemerides of Johann Miiller, since errors in that ephemeris are alleged to have caused errors in the computed longitude. In his 1992 paper, Mr Molander asserted that timing of the conjunction is not required by this method, because Columbus somehow utilizes the Moon's daily topocentric motion. But how this datum is utilized, and in fact all details of the longitude determination itself, are entirely obscure.

On 14 September 1494, Christopher Columbus observed a lunar eclipse while at the island of Saona near the eastern tip of Hispaniola. He later recorded in his Libro de las Profecias that, from his timing of the eclipse, he determined his longitude to be ‘five hours and more than one half’west of Cape San Vicente. His actual longitude was three hours and 59 minutes west of Cape San Vicente, so Columbus was off by over an hour and a half, some 23 degrees of longitude.

During the summer months of 1994 the yacht Jester undertook a seagoing investigation into some of the navigational problems that would have confronted the Portuguese discoverers of the thirteenth and fourteenth centuries returning to mainland Portugal from the coasts of Africa and the Atlantic archipelagos. The investigation was made at the suggestion of the maritime historian D. W. Waters to illuminate one aspect of how astronomical navigation was first introduced at sea in the west.

Captain George Vancouver's survey of the North Pacific coast of America has been characterized as being among the most distinguished work of its kind ever done. For three summers, he and his men worked from dawn to dusk, exploring the many inlets of the coastal mountains, any one of which, according to the theoretical geographers of the time, might have provided a long-sought-for passage to the Atlantic Ocean. Vancouver returned to England in poor health but, with the help of his brother John, he managed to complete his charts and most of the book describing his voyage before he died in 1798. He was not popular with the British Establishment and, after his death, all of his notes and personal papers were lost, as were the logs and journals of several of his officers.

The earliest record of a requirement for ships to carry lights that the author has been able to find is in the Rhodian Laws. These appear to date from about the 3rd or 2nd century B.C., and were certainly incorporated into Roman Law by A.D. 161, although Ashburner suggests that the earliest known copy dates from Byzantine times, A.D. 600–800. The Laws contain a section intended to prevent collisions between vessels under way and vessels at anchor or stopped.

This paper is the fifth chapter of a series on the history of air navigation systems. Comments on the content of the paper would be welcomed by the author and the editor.

I am honoured that the Royal Institute of Navigation has invited me to give the E. G. R. Taylor lecture for 1992. These lectures, held annually, were funded by well-wishes in various societies to celebrate Professor Eva Taylor's 80th birthday. As a scholar, Professor Taylor moved in many spheres. I have chosen a subject which seems appropriate to her pioneering work in the history of navigation and the marine sciences.

The first part of the above title was used in the Journal in 1953 for a paper by Captain Carl V. Solver. His special interest was to discover how the Norse navigators of the Viking age found their way across the North Atlantic. He was the first person to interpret the small wooden disc shown in Fig. i as a fragment of an early bearing-dial and investigations since his paper was published provide considerable supportive evidence. At the time, there was some strong opposition to his views, but he persisted with his theory and wrote a book, Vestervejen. This formed a basis for other researchers to carry his work further and, as a result, there have been many international contributions over some 40 years. The archaeological find from southern Greenland seems to show that the Norse navigator used the path of the Sun's shadow during the day as the basis of a compass.

Zheng He was the greatest navigator in China's history and he conducted major oceanic voyages, before the western ‘Age of Discovery’, at a time when the Portuguese under Prince Henry were just beginning to feel their way down the coast of Africa. Under the orders of Emperor Yongle and then Emperor Xuande in the Ming Dynasty, Zheng He led a fleet which was the greatest in the world in the fifteenth century and made, in all, seven expeditions to the Western Ocean from 1405 to 1433. His fleet sailed across most of the sea areas of the Western Pacific Ocean and the Indian Ocean, and visited more than thirty Asian and African countries and regions. This paper will mainly discuss the extraordinary achievements of Zheng He's expeditions and their navigational technology, and will also briefly evaluate their role in navigational history.

This paper is the third chapter of a series on Air Navigation Systems during the period from the early oceanic flights and the inception of commercial aviation to the introduction of INS in civil aircraft. Some initial comments on the paper are included in the Forum section of this issue of the Journal. Further comments would be welcomed by the author and the editor.

This paper formed the 1990 Anderson Memorial Lecture and was presented to the Bristol Channel Branch on 22 February. In developing his theme, George King concentrated very much on the characters of the navigators concerned with six extraordinary exploits, but without losing sight of the navigation itself. The following version is necessarily much abridged and the editor has reluctantly omitted the detail of fascinating accounts of the expedition commissioned by Thomas Jefferson to explore the American West, the epic open boat voyage by Ernest Shackleton in the Antarctic in 1916, the first solo air crossing of the Atlantic by Charles Lindbergh in 1927, and the spectacularly successful Apollo 11 mission in 1969. The full text of George King's meticulously researched and brilliantly written paper is available to members from the Institute, price £3.