POPT: Chapter 5
Understanding Longitude and the Importance of Accurate Timekeeping
Longitude is a geographic coordinate that specifies the east-west position of a point on Earth. Unlike latitude, which can be measured by observing the angle of the sun or stars above the horizon, longitude requires an accurate method of tracking time. This is because the Earth rotates 15 degrees every hour, and to calculate longitude, one needs to know the exact time difference between the local time and a known reference time (such as Greenwich Mean Time).
For centuries, determining longitude was a significant challenge for navigators. The key to solving this puzzle lay in accurate timekeeping. Once accurate time could be kept at sea, sailors could compare the time at their location to the time at a known reference point (such as Greenwich). The difference in time, multiplied by 15 degrees per hour, would provide the longitude.
In ancient times, the concept of accurate timekeeping was not as straightforward as it is today, but the ability to track time using the human body — particularly heartbeats — provided a unique advantage.
By counting his heartbeats, a priest could create a natural and portable timekeeping system. This was particularly useful in the context of long voyages where mechanical clocks were unreliable or unavailable. The priest, having calibrated his internal clock through daily practice and counting, could maintain an accurate sense of time as he traveled, even when out of sight of land.
This ability to measure time through heartbeats, when applied to navigation, allowed the priest to calculate the difference between local noon at his location and the known noon at a reference point. With this time difference, the priest could estimate how far east or west he had traveled.
For example, if the priest observed that local noon occurred two hours later than at the reference location, he could use the 15-degree-per-hour rule to calculate a longitude difference of 30 degrees east. Conversely, if local noon occurred earlier, it would indicate that he had traveled west.
This time-based calculation could be done without the need for sophisticated tools. Instead, the priest’s body served as the instrument, allowing him to navigate vast distances across the sea. The skill of heartbeat counting, honed through careful practice, made him a valuable asset on a ship.
The Priest as a Living, Breathing Timekeeper on a Ship
The priest, with his carefully cultivated internal clock, was a living, breathing timekeeping device. His skill of counting heartbeats and calibrating his internal clock to match the passage of time made him a valuable tool on long sea voyages. However, this ability was not widely understood, and the people around him viewed his precision with time as something mysterious. They attributed this skill to spiritual power, elevating his status to that of a spiritual leader.
In an era when mechanical clocks were unreliable at best and unavailable at worst, the priest’s ability to maintain an accurate sense of time was invaluable. His method of counting heartbeats, based on a deeply ingrained practice of physical awareness, allowed him to measure the passage of time with remarkable precision.
While sailors and navigators of the time relied on more rudimentary methods of determining position, such as dead reckoning or celestial navigation, the priest's unique timekeeping method provided an additional layer of accuracy. His heartbeats, combined with the observation of local noon and the comparison to a known reference time, gave him the tools to calculate longitude with surprising efficiency.
In this way, the priest became an essential figure, serving as a clock at sea. His ability to track time accurately, through simple counting, made him a key player in early navigation techniques. The secret skill he wielded, though purely practical in nature, led others to perceive him as a figure of spiritual significance, enhancing his status and usefulness.
