London - Edward Rutherfurd [420]
Though Richard Meredith saw Eugene waiting for him, he could not easily break away, since he had a problem with Sir Julius Ducket. It was all the more irritating as he had been looking forward to the celebration of the opening of the building.
It had been especially appropriate, Meredith thought, that his friend and fellow member of the Royal Society, Sir Christopher Wren, the astronomer who had so brilliantly turned his mathematical talents to architecture, should have been the one to design the building. For the small brick, octagonal structure that now presided over the slope above Greenwich was the first of its kind in England: it was the Royal Observatory.
Strangely enough, its primary purpose was not to study the stars – though it contained a telescope of course. The main objective, as Meredith had explained to Sir Julius earlier that morning, was entirely practical.
“It’s to help our mariners,” he told him. “A sailor at present, by using a quadrant, can measure the angle of the sun at its zenith, or certain stars, and work out how far north or south he is. But what they do not know,” he continued “is how far they are to east or west – their longitude. Until now, sailors have had to make a rough guess, usually by how many days they have sailed: hardly satisfactory. Yet there is a way of discovering one’s longitude.
“For consider, Sir Julius. Each day, as the Earth makes its way round the sun – as, despite the old objections of the Roman Church we know it does – the Earth also spins. Because of this, as we know, the sun appears over the eastern horizon here in London, for instance, several minutes before it is seen in the west of England.” Indeed, so well aware of this were men that local time was a highly variable affair. Each city normally set its own clocks according to the hours of daylight, so that the western port of Bristol kept a different time from London.
“We calculate that a difference of four minutes represents one degree of longitude; an hour is fifteen degrees. So you see, if a mariner could take his own time, which he can by the sun, he has only to compare it with our time here in London to discover how far east or west of us he is.”
“If he had a clock that kept perfect London time he could do it.”
“Yes. But we haven’t discovered how to build a clock that will keep time like that at sea. However,” Meredith continued, “we can make such accurate tables of the moon’s position against the backdrop of the heavens that, by reading off his sightings in an almanac, a mariner will know what the time is, at a particular moment, in London. By comparing this standard astronomical clock, as it were, with his local time, he’ll be able to know his longitude.”
“Will it take long to complete these tables?”
“Decades, I should guess. It’s a huge task. But that’s what the Royal Observatory is for: to make a great map of all the heavenly bodies and their motions.”
“So all sailors – from other countries too, I should think – will work out their bearings from a standard London time?”
“Precisely,” Meredith smiled. “If they want to know where they are they’ll follow the time of the Royal Observatory. We shall call it Greenwich time,” he added.
But having taken Sir Julius to the Observatory and shown him its telescope, clock and apparatus, Meredith had suddenly been sidetracked into this stupid conversation. Worse still, he had to admit, it was largely his own fault.
It was a month now since he had allowed the matter to slip out. In doing so – of course he saw that now – he had carelessly assumed that as he himself did not take the matter seriously, the baronet would feel the same. He had been entirely wrong; Sir Julius had been deeply concerned. In fact, he had been terrified; rich Sir Julius Ducket, friend of the king, had shaken with fear, all because poor Jane Wheeler, dying of plague, had laid a curse upon him.
“If she was a witch,” Sir Julius was saying