168 COMPENDIUM OF GEOGRAPHY AND TRAVEL 
therefore be assumed that the wave did not originate 
merely from the island, but from a wider submarine 
upheaval. The hydrographic surveys subsequently under¬ 
taken show that over an area of 7 2 square miles the depths 
were greatly reduced by the eruption. Over a large portion 
of this there are now soundings of 12 feet only where 
formerly there was an uniform depth of 120 feet. 
Although, as has been stated, various seismic waves were 
recorded on the neighbouring shores, most of them were 
not of extraordinary height. The great loss of life and 
property was chiefly occasioned by the single gigantic 
wave which occurred at 10 o’clock on the morning of the 
2 7th August. The destruction caused by it was immense. 
It may be said, roughly speaking, that all the coast 
villages and towns of the Straits of Sun da were over¬ 
whelmed. The actual height of the crest of the wave 
above sea-level has been variously estimated, and no 
doubt varied greatly according to the locality. Mr. 
Yerbeek, in his plan, shows the hills of Merak to have 
been washed by the water to the height of 115 feet, 
and at Telok Betong, on the Sumatran coast, the water 
reached within 6 feet of the Residency, which stands on 
a hill 7 8 feet above the sea. A still better illustration 
of its height and volume is afforded in the case of the 
Dutch man-of-war “ Berouw,” anchored off this place, 
which was carried more than one mile and three-quarters 
inland, and left more than 30 feet above the level of the 
sea. The distance to which this wave was propagated is 
very remarkable. It was felt not only in South Africa, 
distant some 5000 miles from the scene of the eruption, 
but also at Cape Horn (7500 miles), and, possibly, in the 
English Channel (11,000 miles). In Ceylon even the 
smaller waves were distinctly recorded. To the north 
the numberless islands of the archipelago soon destroyed 
