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 was 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 western end of the reef and the cen- 

 ter of the Tortugas group. The little harbor 

 was perfectly protected, affording safe facilities 



