FOULING OF SHIPS' BOTTOMS 249 



11. Vessels that are never in port for more than a few days at a time, and whose 

 next port of call is at a considerable distance, rarely if ever accumulate much fouling. 



12. Each vessel shows at the time of diy docking the visible record of its cruise 

 by the diverse types of organisms found on her hull. 



13. Fresh water kills most of the organisms that cause fouling within 72 hours, 

 but if calcareous or chitinous growths already have been formed, such materials 

 remain and the resistance is not materially lessened. 



14. Certain species of barnacles grow at a very rapid rate, attaining a size of 

 2 inches and becoming sexually mature within 60 days. 



15. Fouling can be predicted from a knowledge of seasonal abundance of larval 

 organisms in given ports. 



16. Certain barnacles are found attached on certain substances and in limited 

 regions, indicating a relation between attachment and the nature of the surface. 



17. Light has been found to be an important factor governing the attachment 

 of the larvse of the forms that cause fouling. 



18. At the time of attachment the larvse of Balanus improvisus and B. ampliitrite 

 are negative to light. (Most of the forms found on ships' bottoms probably are 

 of a similar nature.) 



19. Light in the field of green and blue has been demonstrated to have the 

 maximum stimulating efficiency for the cyprid larvse of several barnacles. 



20. This report indicates the value of an intensive study of seasonal periodicity 

 of fouling organisms, of the relation between fouling organisms at the time of attach- 

 ment and surface films, and a study of properly prepared paints of lighter colors 

 than those now in general use. 



BIBLIOGRAPHY 

 Adamson, N. E. 



1922. U. S. Navy research of ships' bottoms paint. Circular No. 156, Educational Bureau, 

 Scientific Section, Paint Manufacturers' Association of the United States. Wash- 

 ington. 

 Albbrti, Leone Battista. 



1470. De re aedificatoria. (German translation by V. Hoffman, Frankenburg, 1883.) 

 American" Society for Testing Materials. 



1924. Report of subcommittee No. XXIII on antifouling paints. Proceedings, American 



Society for Testing Materials, vol. 24, part 1, pp. 291-505. Philadelphia. 



1925. Fifth annual report of subcommittee No. XXIII on antifouling paints. Ibid., vol. 25, 



part 1, pp. 244-247. Philadelphia. 

 Athenabus. 



200 B. C. Deipnosophistee. (English translation by C. D. Yonge in Bohn's Classical Library, 

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 Atwood, William G., and A. A. Johnson. 



1924. Marine structures, their deterioration and preservation; report of the committee on 

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 Beat, A. W. 



1923. A preliminary investigation into the fouling of ships' bottoms by marine growths. 

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 Brooks, W. K. 



1880, Development of the American oyster. Studies from the Biological Laboratory, Johns 

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