Hal hummed softly to himself as he concentrated on the task, conscious of the eyes upon him. Yet he did not sense the importance of this discharge and was oblivious of his father's prayers. It was a game to him, just another chance to excel. Hal liked to win, and each time he did so he liked it better. The young eagle was beginning to rejoice in the power of his wings.

Gripping the end of the long brass monkey tail, he swivelled the falconer downwards, peering over the yard long barrel, lining up the notch above the pan with the pip on the muzzle end.

He had learned that it was futile to aim directly at the target. There would be a delay of seconds from when he applied the slow-match, to the crash of the shot, and in the meantime ship and cask would be moving in opposite directions. There was also the moment when the discharged balls were in flight before they struck. He must gauge where the cask would be when the shot reached it and not aim for the spot where it had been when he pressed the match to the pan.

He swung the pip of the foresight smoothly over the target, and touched the glowing end of the match to the pan. He forced himself not to flinch away from the flare of burning powder nor to recoil in anticipation of the explosion but to keep the barrels swinging gently in the line he had chosen.

With a roar that stung his eardrums the falconer bucked heavily against its swivel, and everything disappeared in a cloud of grey smoke. Desperately he craned his head left and right, trying to see around the smoke, but it was the cheers from the decks below that made his heart leap, reaching him even through his singing ears. When the wind whisked away the smoke, he could see the ribs of the shattered cask swirling and tumbling astern in the ship's wake. He hooted with glee, and waved his cap at the faces on the deck far below. Aboli was at his place in the bows, coxswain and gun captain of the first watch. He returned Hal's beatific grin and beat his chest with one fist, while with the other he brandished the cutlass over his bald head.

The drum rolled to end the drill and stand down the crew from their battle stations. Before he dropped down the shrouds Hal reloaded the falconet carefully and bound a strip of tar-soaked canvas around the pan to protect it from dew, rain and spray.

As his feet hit the deck he looked to the poop, trying to catch his father's eye and glean his approbation. But Sir Francis was deep in conversation with one of his petty officers. A moment passed before he glanced coldly over his shoulder at Hal. "What are you gawking at, boy? There are guns to be reloaded."

As he turned away Hal felt the bite of disappointment, but the rowdy congratulations of the crew, the rough slaps across his back and shoulders as he passed down the gundeck, restored his smile.

When Ned Tyler saw him coming he stepped back from the breech of the culverin he was loading and handed the ramrod to Hal. "Any oaf can shoot it, but it takes a good man to load it," he grunted, and stood back critically to watch Hal measure a charge from the leather powder bucket. "What weight of powder?" he asked, and Hal gave the same reply he had a hundred times before.

"The same weight as that of the round shot."

The black powder comprised coarse granules. There had been a time when, shaken and agitated by the ship's way or some other repetitive movement, the three essential elements, sulphur, charcoal and saltpetre, might separate out and render it useless. Since then the process of "coming" had evolved, whereby the fine raw powder was treated with urine or alcohol to set it into a cake, which was then crushed in a ball mill to the required size of granules. Yet the process was not perfect and a gunner must always have an eye for the condition of his powder. Damp or age could degrade it. Hal tested the grains between his fingers and tasted a dab. Ned Tyler had taught him to differentiate between good and degenerate powder in this way. Then he poured the contents of the bucket into the muzzle, and followed it with the oakum wadding.

Then he tamped it down with the long wooden-handled ramrod. This was another crucial part of the process: tamped too firmly, the flame could not pass through the charge and a misfire was inevitable, but not tamped firmly enough, and the black powder would burn without the power to hurl the heavy projectile clear of the barrel. Correct tamping was an art that could only be learned from prolonged practice, but Ned nodded as he watched Hal at work.

It was much later when Hal scrambled up again into the sunlight. All the culver ins were loaded and secured behind their ports and Hal's bare upper body was glistening with sweat from the heat of the cramped gundeck and his labours with the ramrod. As he paused to wipe his streaming face, draw a breath and stretch his back, after crouching so long under the cramped head space of the lower deck, his father called to him with heavy irony, "Is the ship's position of no interest to you, Master Henry?"

With a start Hal glanced up at the sun. It was high in the heavens above them: the morning had sped away. He raced to the companionway, dropped down the ladder, burst into his father's cabin, and snatched the heavy backstaff from its case on the bulkhead. Then he turned and ran back to the poop deck.

"Pray God, I'm not too late," he whispered to himself, and glanced up at the position of the sun. It was over the starboard yard-arm. He positioned himself with his back to it and in such a way that the shadow cast by the main sail would not screen him, yet so that he had a clear view of the horizon to the south.

Now he concentrated all his attention on the quadrant of the backstaff. He had to keep the heavy instrument steady against the ship's motion. Then he must read the angle that the sun's rays over his shoulder subtended onto the quadrant, which gave him the sun's inclination to the horizon. It was a juggling act that required strength and dexterity.

At last he could observe noon passage, and read the sun's angle with the horizon at the precise moment it reached its zenith. He lowered the backstaff with aching arms and shoulders, and hastily scribbled the reading on the traverse slate.

Then he ran down the ladder to the stern cabin, but the table of celestial angles was not on its shelf. In distress he turned to see that his father had followed him down and was watching him intently. No word was exchanged, but Hal knew that he was being challenged to provide the value from memory. Hal sat at his father's sea-chest, which served as a desk, and closed his eyes as he reviewed the tables in his mind's eye. He must remember yesterday's figures and extrapolate from them. He massaged his swollen ear-lobe, and his lips moved soundlessly.