IN THE CORAL COUNTRY. 33 



quarters, and even played a game of base-ball 

 on the pleasant parade-ground, turfed with Ber- 

 muda and a thick wiry grass. 



Their island home comprised thirteen acres, 

 most of which w r as covered by the fort, then 

 being erected by the Engineer Department of the 

 United States. The fort, one of the largest of 

 its kind in America, was built of brick, was half 

 a mile around, with three tiers of guns, and sur- 

 rounded by a moat eight or ten feet deep, the 

 only entrance being the sally-port, through which 

 the boys had passed ; even this could be closed 

 by a heavy drawbridge, making the grim fortress 

 completely inaccessible. 



The island was made up of ground coral, 

 shell, and the hard portions of a lime-secreting 

 sea-weed, and was so low that it would have 

 been washed away time and time again by the 

 hurricanes had not, as Tom said, the fort and its 

 sea-wall held it down. 



Their home was a portion of a growing atoll 

 on the very w r estern end of the reef and the cen- 

 ter of the Tortugas group. The little harbor 

 was perfectly protected, affording safe facilities 



