The theme for an upcoming issue of [[Worldbuilding Magazine]] is "Cosmology," which makes me think of the cosmos / stars. It inspired a flash fiction piece involving sailing in the [[Bronze Age]], which means it's time for some research. This week, I looked at the history of magnets and compasses to learn more about what kind of navigation my characters will be limited to. ## Fun Facts - Lodestones are basically chunks of magnetite that have been magnetized, probably by lightning strikes. - The [[Olmecs]] of [[Mesoamerica]], who did not use iron, were probably the first civilization to use lodestones as directional devices, back in 1200 BCE. - Lodestones work best when suspended (for example, by a piece of string), so that they can spin freely. - Star charts are typically oriented with west to the right, unlike a normal chart, to allow a navigator to hold the chart overhead. - Pole stars move over time. Currently Polaris is the Northern Pole Star, but in [[classical antiquity]], the midpoint between two pole stars was considered "due North." ### The South Pointer One early compass, crafted from lodestone shaped like a spoon and mounted in a bronze bowl, was probably made in [[China]] around the 2nd century BCE. It was designed to point south. (<a href="https://www.magnet-shop.com/magnets-throughout-the-history">Source</a>) ### Crystals for Clouds [[Vikings]] were able to navigate the open seas using sundials on sunny days, and according to the Sagas may have even been able to use crystals and the polarization of ambient daylight to navigate by. (<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3049005/">Source</a>) ### Bronze & Shell Archaeologists found a compass made out of a hollowed out cylindrical shell in the ruins of the [[Harappan]] Civilization in the Indus Valley from roughly 2300 BCE. It has the necessary markings to function as a sextant for celestial navigation with the addition of a bronze wire. (<a href="http://drs.nio.org/drs/bitstream/handle/2264/3082/J_Mar_Archaeol_3_61.pdf?sequence=2">Source</a>) ### Clenched Fists Some constellations shift, rising and setting throughout the year, while others, remain static. Sailors can determine their latitude by measuring the angle of these circumpolar stars above the horizon. Without tools, sailors can guess latitude because an outstretched fist is about 10° of latitude. (<a href="https://www.formulaboats.com/blog/navigate-using-stars/">Source</a>) <div class=infobox>If you found this interesting, you may also enjoy </div>