A truly celestial man

Twenty years ago C. A. Ronan wrote a biography of Edmond Halley. The subtitle was Genius in Shadow, and in one way this was appropriate enough, because in the popular mind Halley has always remained in the shadow of his contemporary, Isaac Newton. Yet this is not justifiable. Of course, Newton was a mathematician beyond compare, but Halley was what we would nowadays call an all-rounder: an astronomer, navigator, engineer, undersea explorer, classical scholar, practical seaman and diplomat. His fields of interest were much wider than Newton's, and in many of these his influence was long lasting.

This new biography of Halley puts the record straight. Alan Cook is particularly well qualified to write it. He was educated at Cambridge, worked on radar during the second world war, took a degree in geophysics and has worked at the National Physical Laboratory on very precise methods of measurement. Therefore his interests overlap Halley's, as is evident by the way in which his book has been written. Certainly he has chosen an apt subtitle, Charting the Heavens and the Seas.

The book is divided into three parts: "The young astronomer (1656-87)", "Often at sea (1688-1703)", and "Scholar and sage (1704-42)". Halley did not become astronomer royal until 1720 when he was already well over 60 years of age, and in the years following 1688 his main concern was in navigation and hydrography. He also spent a relatively brief period taking charge of the Royal Mint at Chester.

He came from a reasonably well-to-do family and made his way to Oxford University, but left before taking his degree in order to undertake an expedition to St Helena, where he hoped to survey the southern stars which never rise above the horizon in England. Despite numerous problems, including bad weather and an uncooperative island governor, he produced a very good catalogue, which established him as a leading observer. Oxford promptly awarded him an honorary degree. Before long he was also given a chance to show his diplomatic skills. There had been a dispute between John Flamsteed, now in charge of the Greenwich Observatory, and the Danzig astronomer Hevelius. The point at issue was the relative usefulness of open and telescopic sights. Hevelius preferred open sights and was bitterly offended by some published criticisms made by Flamsteed and, more forcefully, by Robert Hooke. In 1679 Halley paid a visit to Hevelius, probably at the direct request of the Royal Society, and was able to smooth matters over.

In the early 1680s he made observations of two bright comets, though it was not until much later that he was able to show that one of these - the comet of 1682 - returned every 76 years; this is, of course, the comet we now call after him.

Cook deals fully with all these developments and also with Halley's role in the publication of Newton's Principia. Without Halley it is unlikely that the Principia would have been completed and scientific progress would have been considerably delayed. Halley even paid for the publication. This entailed a decided financial risk because, though Halley was not a pauper, neither was he rich. In 1686 he even took a salaried post with the Royal Society and it is on record that on one occasion part of his salary was paid not in cash, but in 50 copies of a totally unsaleable book about fishes.

Halley was above all an astronomer, but Cook is careful to point out that his contributions to navigation were equally important, at least at the time. He went on long, often highly dangerous sea trips in order to study the earth's magnetic field and also to carry out general surveys. One of these trips took him into the Antarctic, where icebergs posed a real threat. Quite apart from the purely scientific aspect, Halley also had to take command of his ship after trouble with his senior lieutenant - and showed himself to be a seaman as skilled as any. As Cook so rightly says: "He was a man who got things done." Certainly, he was very much at home when sailing. The austere Flamsteed once made the sour comment that Halley "talked, swore and drank brandy like a sea-captain", which he undoubtedly did.

When it became necessary to survey the Adriatic ports so that they could be used by English ships in time of war, it was Halley who was dispatched to carry out the task, which he did with conspicuous success. As Cook comments: "We see him carrying out his mission speedily and competently and gaining the admiration and respect of all he met I When he returned and saw how little had been accomplished, he ceased to be just the expert adviser and became the site engineer, driving on the commissioners and the workmen to finish the construction before the onset of winter." This tells us a great deal about Halley's character.

In 1703, Halley left the sea for the last time, and returned to the purely academic world, first as an outstanding classical scholar and then as astronomer royal. It was typical of him that on arrival at Greenwich he decided to undertake a series of measurements of the moon's movements which he knew would take him over 20 years, and it was equally typical that he carried through the programme even when he was over 80 years old. He re-equipped the observatory and used the instruments well. His health remained good until his last few years and even when his physical powers were failing he continued to work, to publish, to visit London and to attend meetings of the Royal Society, with which he had been so closely associated throughout his life.

The book is a mine of information and the extensive references and notes ensure that the serious student will find it invaluable, but it is also so clearly written that it will also appeal to the more casual reader. Nothing important has been left out and no attempt is made to gloss over the various disputes and quarrels that went on between the leading scientists of the time; human nature does not change. In fact Halley was involved in very few of these disputes because he was a remarkably genial and gregarious man and few people disliked him, apart from Flamsteed, who, we may suppose, did not appreciate Halley's strong sense of humour.

One episode is not mentioned in the book. The tsar of Russia, Peter the Great, paid avisit to England to learn about shipbuilding, and struck up a friendship with Halley. This is mentioned, but not the occasion when, if rumour is to be believed, a somewhat alcoholic evening ended with the tsar getting into a wheelbarrow and being pushed througha hedge. No doubt it has been omitted because its authenticity is not absolute, though one has a distinct feeling that it really did happen.

Errors and misprints are conspicuous only by their absence, but it might have been useful to point out that transits of Mercury across the face of the sun occur in May and November by our modern calendar, and not in April and October, as stated on page 219.

Halley lived in fascinating times, and Cook gives a vivid account of them; characters such as Wren, Pepys, Handel, Purcell and Hooke flit through the pages, and all were well known to Halley. Halley is, after all, one of the greatest of all English scientists. Only in the field of pure mathematics does he rank below Newton.

As a study of Halley's life, times and accomplishments this book could hardly be bettered and it is certain to remain the standard work for many years to come. It is moreover well produced and printed and the illustrations match the quality of the text.

After reading the book one feels that it would have been a great pleasure to meet Halley. He was a great man in every sense of the term and also an attractive one. It is significant that his very last act on earth, before his death in 1742, was to call for a glass of wine - and drink it.

Patrick Moore is an astronomer who has specialised in studiesof the moon. He is a past president, British Astronomical Association.