670 BOWMAN— ECOLOGY AND 



West Indian Islands the manufacture of charcoal from mangrove 

 wood. On the Marquesas atoll there are now remnants of old char- 

 coal burners' huts. The hai'd, dense quality of the wood and the 

 plentiful supply at hand stimulated the industry in the days when 

 charcoal was used more largely as a fuel, mangrove charcoal being 

 of a very good quality. 



As noted before the main application of the mangrove to man's 

 wants has been for ages its utilization as a source of tannic acid. 

 This is still carried on in a fairly large scale and there are several 

 places in Florida in which there are factories for the manufacture 

 of tannic acid from mangrove bark. Mr. Mills has told the writer 

 of a factory at Charleroi, Fla., which produced large quantities of 

 tannic acid from the bark. 



The latest use of the mangrove in a practical way and one of 

 which the writer has personal knowledge is the use of these trees 

 as ballast retainers. This has been effectively demonstrated by the 

 Florida East Coast Railway which has used the peculiar habit of 

 the mangrove to advantage in their great feat of engineering, viz., 

 the Oversea extension. At certain places these keys are con- 

 nected by embankments supporting the road bed or where the bed 

 is built high over a low, fiat key the mangroves have been planted 

 to prevent the erosive action of the sea on the ballast. This has 

 been of greatest importance to the railroad and has protected the 

 dykes just as the mangroves naturally sown have formed and pro- 

 tected young islands. Still more recently the writer has been of some 

 small service to a large asphalt company concerning their engineer- 

 ing projects in Venezuela in which it is proposed to plant RJii::o- 

 phora mangle along the dykes and jetties, etc., as a ballast retainer. 

 This, it is hoped, will prove as efficient as the plantings of the 

 Florida East Coast Railway' have been in aiding the engineer in the 

 tropics. 



Summary. 



I. The historical references to the mangroves are well authenti- 

 cated and fall into three periods, viz., the classical references from 

 Nearchus (325 B.C.) and Theophrastus to Arrian (136 A.D.) ; the 

 Middle Age and later references from Abou '1 Abbas en-Nebaty 



