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Mendaña had landed on them but had incorrectly fixed their longitude. And even if, through some celestial guidance, he had managed to fix them correctly, then other navigators looking for that longitude (and he himself on his second voyage) could not be entirely sure of their own longitude.

For several centuries the great European maritime powers strove to discover a way of establishing the fixed point—the punto fijo that Cervantes had joked about—and were prepared to pay enormous sums to anyone who found an effective method. Navigators, men of science, and cranks came up with all kind of answers—there was the method based on lunar eclipses, one that examined the variations of a magnetized needle, and the loch, or Dutchman’s log method; Galileo proposed a technique based on the eclipses of the satellites of Jupiter, which are so frequent that they can be seen several times each night.

But all turned out to be inadequate. There would, of course, have been one sure method: to keep a clock on board that tells the time at one known meridian, then to find out the time at place X at sea and, by working on the basis that the globe has been subdivided since antiquity into 360 degrees of longitude and that the sun moves 15 degrees in one hour, to work out the longitude of point X from the difference. In other words, if the clock on board showed that it was, let us say, noon in Paris, and that in place X it was six in the afternoon, by translating every hour of difference into 15 degrees, we would have known that the longitude of place X was 90 degrees from the Paris meridian.

Although it was not difficult to work out the time at the place where the calculation was being made, it was practically impossible to keep a mechanical clock on board that would function perfectly after months of sailing and the inevitable jolts, through winds and waves; hourglasses and water clocks were, of course, out of the question since they need to work on a flat motionless surface. And any clock would have to be of an extremely high precision: an error of four seconds would produce an error of one degree of longitude.

One suggestion mentioned in various chronicles of the time was the use of Powder of Sympathy.

This was a miraculous compound that, when applied to the weapon that had caused a wound, acted (through a sort of almost atomic continuity) on the particles of blood released into the air over the wound, even if the weapon and the injury were a great distance apart. This would heal the wound, allowing time to take its course, but as an immediate reaction it would cause irritation and pain.

It was therefore decided to wound a dog, to be kept on board the ship during the journey, and to rub the miraculous compound over the weapon each day at the same hour. The dog would have reacted with a whimper of pain and that was how they would know aboard ship what time it was at that moment at the point of departure.3

I dealt with this story in my novel The Island of the Day Before, so allow me to quote one passage since, after all, on such uncertain information, this is the only document that suggests what must have occurred.

Finally one morning, taking advantage of a sailor’s bad fall from a yardarm, which fractured his skull, while there was great confusion on the deck and the doctor was summoned to treat the unfortunate man, Roberto slipped down into the hold. Almost groping, he managed to find the right path. Perhaps it was luck, or perhaps the animal was whimpering more than usual that morning: Roberto, more or less at the point where later on the Daphne he would find the kegs of aqua vitae, was confronted by a horrid sight. Well shielded from curious eyes, in an enclosure made to his measure, on a bed of rags, lay a dog.

He was perhaps of good breed, but his suffering and hunger had reduced him to mere skin and bones. And yet his tormentors showed their intention to keep him alive: they had provided him with abundant food and water, including food surely not canine, subtracted from the passengers’ rations. He was lying on one side, head limp, tongue lolling. On that exposed side gaped a broad and horrible wound. At once fresh and gangrenous, it revealed a pair of great pinkish lips, and in the centre, as along the entire gash, was a purulent secretion resembling whey. Roberto realized that the wound looked as it did because the hand of a chirurgeon, rather than sew the lips together, had deliberately kept them parted and open, attaching them to the outer hide.

Bastard offspring of the medical art, that wound had not only been inflicted but wickedly treated so it would not form a scar and the dog would continue suffering—who knows for how long. Further, Roberto saw in and around the wound a crystalline residue, as if a doctor (yes, a doctor, so cruelly expert!) every day sprinkled an irritant salt there.

Helpless, Roberto stroked the wretch, now whimpering softly. He asked himself what he could do to help, but at a heavier touch, the dog’s suffering increased. Moreover, Roberto’s own pity was giving way to a sense of victory. There was no doubt: this was Dr. Byrd’s secret, the mysterious cargo taken aboard in London.

From what Roberto had seen, from what a man with his knowledge could infer, the dog had been wounded in England, and Byrd was making sure he would remain wounded. Someone in London, every day at the same, agreed hour, did something to the guilty weapon, or to a cloth steeped in the animal’s blood, provoking a reaction, perhaps of relief, but perhaps of still greater pain, for Dr. Byrd himself had said that the Weapon Salve could also harm.

Thus on the Amaryllis they could know at a given moment what time it was in Europe. And knowing the hour of their transitory position, they were able to calculate the meridian! (translated by William Weaver)

If the story about the dog seems fanciful, in the same novel I described an instrument proposed by Galileo in a letter of 1637 (to Lorenzo Realio). Galileo thought of fixing longitude by observing the positions of Jupiter’s satellites. But once again, on a ship at the mercy of the waves, it would be difficult to point the telescope accurately. And here Galileo suggested an extraordinary solution. To enjoy its comedy, we need not read the humorous account in my novel—it is enough to read Galileo himself:

As for the first problem, this is certainly the most difficult, but I think I have found a remedy for this, at least for the ordinary movements of the ship; and this should be enough since, during great storms and tempests, which normally prevent the sun and other stars being seen, all other observations cease, as indeed do all mariner’s duties. But during ordinary movements I think it is possible to reduce the state of the person who has to make the observations to a tranquility similar to that of the peace and calm of the sea; and to achieve this benefit I have thought of placing the observer in a specially prepared part of the boat so that he does not feel either the movements from bow to stern or the rocking from side to side: and my thinking is based on this. If the ship is always in calm waters and without waves, there is no doubt that the use of the telescope would be just as easy as on land. Now, I want to place the observer in a small boat placed inside the large boat, the small boat being in such necessary quantity of water as I will explain below. Here, first of all, it is clear that the water contained in the small vessel will remain in equilibrium, even when the large boat inclines and reclines to right and left, forward and backward, without any part of it being raised or lowered, but will always remain parallel to the horizon; so that if in this small boat we build another smaller boat, floating in the water contained within it, it would find itself in an extremely calm sea, and would therefore stay there without moving: and this second boat is the place where the observer must be placed. I therefore want the first vessel, which has to contain the water, to be like a large semi-spherical basin, and that the smaller vessel is similar to it, except that it is smaller, and that the space between its convex surface and the concave inner surface of the container is no more than the thickness of a thumb; so that a very small quantity of water will be enough to float the inner vessel, as if it were floating in the wide ocean . . . The size of these vessels must be such that the inner and smaller vessel can hold the weight of the person making the observations without sinking, as well as his chair and the other equipment on which the telescope is fixed. And in order to keep the smaller vessel separate from the outer one so as not to touch it, so that it cannot be influenced by the motion of the ship in the same way that the larger one is, I want the internal concave surface of the inner vessel to be held with several springs, eight or ten in number, which stop the two vessels from touching each other, but do not prevent the inner vessel from not responding to the raising and lowering of the sides of the outer container: and if, rather than water, we wish to use oil, that would be even better, nor would the quantity be great, since two or three barrels would be enough . . .