Birds of Prey Read Online Free PDF Page B

movement, the three essential elements, sulphur,
charcoal and saltpetre, might separate out and render it useless. Since then the process of ‘corning’ 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 blackpowder 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 culverins 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 headspace 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.
    Suddenly his face lightened, he opened his eyes and scribbled another number on the slate. He worked for a minute longer, translating the angle of the noon sun into degrees of latitude. Then he
looked up triumphantly. ‘Thirty-four degrees forty-two minutes south latitude.’
    His father took the slate from his hand, checked his figures, then handed it back to him. He inclined his head slightly in agreement. ‘Close enough, if your sun sight was true. Now what of
your longitude?’
    The determination of exact longitude