270 THE TROPICAL WORLD. 



their food. From a projecting cape, or looking down upon 

 the play of waters, may be seen the month of the cave of Grua 

 Eongkop, sometimes completely hidden under the waves, and 

 then again opening its black recesses, into which the swallows 

 vanish, or from which they dart forth with the rapidity of light- 

 ning. While at some distance from the coast the blue ocean 

 sleeps in peace, it never ceases to fret and foam against the 

 foot of these mural rocks, where the most beautiful rainbows 

 glisten in the rising vapour. 



Who can explain the instinct which prompts the birds to 

 glue their nests to the high dark vaults of those apparently 

 inaccessible caverns ? Did they expect to find them a safe 

 retreat from the persecutions of man ? Then surely their 

 hopes were vain, for where is the refuge to which his insatiable 

 cupidity cannot find the way ? At the cavern of Grua Grede the 

 brink of the coast lies eighty feet above the level of the sea 

 at ebb-tide. The wall first bends inwards, and then at a 

 height of twenty-five feet from the sea throws out a projecting 

 ledge, which is of great use to the nest-gatherers, serving as a 

 support for a rattan ladder let down from the cliff. The roof 

 of the cavern's mouth lies only ten feet above the sea, which 

 even at ebb-tide completely covers the floor of the cave, while 

 at flood-tide the opening of the vast grotto is entirely closed 

 by every wave that rolls against it. To penetrate into the 

 interior is thus only possible at low water, and during very 

 tranquil weather, and even then it could not be done if the 

 roof were not perforated and jagged in every direction. 



The boldest and strongest of the nest-gatherers wedges him- 

 self firmly in the hollows, or clings to the projecting stones 

 while he fastens rattan ropes to them, which then hang four or 

 five feet from the roof. To the lower end of these ropes long 

 rattan cables are attached, so that the whole forms a kind of 

 suspension bridge, throughout the entire length of the cavern, 

 alternately rising and falling with its inequalities. The cave 

 is 100 feet broad and 150 feet long, as far as its deepest 

 recesses. If we justly admire the intrepidity of the St. 

 Kildans, who, let down by a rope from the high level of their 

 rocky birthplace, remain suspended over a boisterous sea, we 

 needs must also pay a tribute of praise to the boldness of the 

 Javanese nest-gatherers, who, before preparing their ladders 



