In February 1681, two individuals traveling through the Straits witnessed the eruption of Krakatoa. Johann Wilhelm Vogel, a mining assayer, was told that the eruption began in May 1680. Since they were passing to the north of the island, it is apparent that the cone they witnessed was Perboewatan. This is backed up by Verbeek's visit in 1880, during which he took samples from a fresh-looking lava flow on the northern coast. The flow was unweathered, with little vegetation, indicating recent origin.