Photographed on May 27, 1883 by visitors to the island, Perboewatan is the only cone on Krakatoa of which quality pre-1883 photographs exist. In the photos, it appears to be a low hill with a flat top. Climbers reported the erupting crater to be about across at the top, narrowing to at the bottom and 500-800 ft deep. Samples were collected, revealing upon analysis a silica (SiO2) content of 65%.