316 CORALS AND CORAL ISLANDS. 
the continents, and occasionally a devastating wave sweeps 
across the land. During the heavier gales, the natives some- 
times secure their houses by tying them to the cocoanut trees, 
or toa stake planted for the purpose. A height of ten or 
twelve feet, the elevation of their land, is easily overtopped 
by the more violent seas; and great damage is sometimes 
experienced. The still more extensive earthquake-waves, 
such as those which have swept up the coast of Spain, Peru, 
and the Sandwich Islands, would produce a complete deluge 
over these islands. We were informed by both Grey and 
Kirby that effects of this kind had been experienced at the 
Gilbert Islands; but the statements were too indefinite to 
determine whether the results should be attributed to storms, 
or to this more violent cause. 
But while coral islands have their storms, the region in 
their vicinity is generally one of light winds and calms, even 
when the trades are blowing strongly all around them. The 
heated air which rises from the islands lifts the currents to a 
considerable height above the island. J.D. Hague mentions 
that on Jarvis’ and the two neighboring islands, under the 
equator, near 180° in longitude from Greenwich, he “ often 
observed the remarkable phenomenon of a rain squall ap- 
proaching the island, and, just before reaching it, separat- 
ing into two parts, one of which passed by on the north, the 
other on the south side, the cloud having been cleft by the 
column of heated air rising from the white coral sands.” 
An occasional log drifts to the shores, and at some of the 
more isolated atolls, where the natives are ignorant of any 
land but the spot they inhabit, they are deemed direct gifts 
from a propitiated deity. These drift-logs were noticed by 
Kotzebue, at the Marshall Islands, and he remarked also that 
they often brought stones in their roots. Similar facts have 
