lodestone

There, copper plates near the entrance bear snippets of Morse code, and a naturally magnetized lodestone sits by a compass rose etched in granite.

这面铜板离入口很近，在入口的地方刻有一段莫尔斯电码，旁边还有一块天然磁石摆放在一块刻有罗盘刻度的花岗岩上。