Editing Geophysics (section)

=== Ancient and classical eras ===
[[Image:EastHanSeismograph.JPG|thumbnail|upright|Replica of [[Zhang Heng]]'s seismoscope, possibly the first contribution to [[seismology]] |alt=Picture of ornate urn-like device with spouts in the shape of dragons]]
The magnetic compass existed in China back as far as the fourth century BC. It was used as much for [[feng shui]] as for navigation on land. It was not until good steel needles could be forged that compasses were used for navigation at sea; before that, they could not retain their magnetism long enough to be useful. The first mention of a compass in Europe was in 1190 AD.<ref>{{harvnb|Temple|2006|pp=162–166}}</ref>

In circa 240 BC, [[Eratosthenes]] of Cyrene deduced that the Earth was round and measured the [[circumference of Earth]] with great precision.<ref name="russo273277">{{cite book |last=Russo |first=Lucio |author-link=Lucio Russo |date=2004 |title=The Forgotten Revolution |url=https://archive.org/details/forgottenrevolut00russ_217|url-access=limited |location=Berlin |publisher=Springer |page=[https://archive.org/details/forgottenrevolut00russ_217/page/n277 273]–277}}</ref> He developed a system of [[latitude]] and [[longitude]].<ref name=Eratosthenes>{{harvnb|Eratosthenes|2010}}</ref>

Perhaps the earliest contribution to seismology was the invention of a [[seismoscope]] by the prolific inventor [[Zhang Heng]] in 132 AD.<ref>{{harvnb|Temple|2006|pp=177–181}}</ref> This instrument was designed to drop a bronze ball from the mouth of a dragon into the mouth of a toad. By looking at which of eight toads had the ball, one could determine the direction of the earthquake. It was 1571 years before the first design for a seismoscope was published in Europe, by [[Jean de Hautefeuille|Jean de la Hautefeuille]]. It was never built.<ref name=Dewey>{{harvnb|Dewey|Byerly|1969}}</ref>