49 



borers or ihu tlegreu of their allaek. Tlie arri\al ol a lu-a\\' intestation does not permit 

 delayed research or temporizing; command of a practical knowledge ot the subject is 

 required so that in the case of a large prfiject the matter can be placed before those in 

 executive control in time to permit authorization of necessary expenditures and execu- 

 tion of protective measures. 



While the research work of this Committee has centered essentially about borer 

 attack on timber, it has necessarily given consideration to the general subject of marine 

 piling materials, including materials other than timber and which are ordinarily, if 

 not alwa\s, immune from borer attack. The availability of timber, its natural adapt- 

 ability as piling, its comparatively low cost and ease of handling, cause it to rank 

 foremost as a piling material for general use. The borers achieve prime importance 

 because they obstruct the use of this most plentiful and available natural piling ma- 

 terial, and not because they constitute a greater problem than any other adverse 

 conditions. .An effort has been made to ascertain the comparative advantages of the 

 various piling materials and to indicate the adaptability- of each to specific conditions. 

 Thus the solution of the problem has been sought in a broad way, considering borer 

 attack as one of many destructive influences to be resisted by utilizing all available 

 means. 



The general study has demonstrated that more than one solution of the problem 

 may be practicable, and that the degree of success obtained in specific cases depends 

 primarily upon the tlegree of understanding of the factors involved. If any of the 

 numerous atherse influences operating on a structure are neglected, the best of ma- 

 terials may be prematureU' destroyed. Materials are available capable of giving an 

 economic life suitable to almost any combination of conditions; the problem is one of 

 finding the proper way in which to use those materials. It is not improbable that suc- 

 cessful use can be made of man>- of the practices developed during the past but con- 

 fidence in which has been shaken by the occurrence of failures. Such failures have 

 sometimes resulted in cases where great effort and elaborate methods were applied, 

 and failure was interpreted as indicating that the entire principle involved was wrong; 

 yet it is commonly found that premature failures are traceable to neglected or improper 

 details. While recognizing the possibility of great advance in knowledge in the future, 

 we have surely reached the point, therefore, where we may profit by the past experi- 

 ments in which we have clear evidence that methods are as critical as mediums and 

 that economy or loss will result according as proper measures are adopted or neglected 

 for both methods and mediums. 



In the function of the engineer to create structures with the greatest economy, he 

 is constantly in search of more efficient practices, and has frequent recourse to experi- 

 ment and test. It is therefore important that he know of those principles which have 

 proved unsuccessful, as well as of those which have proved successful. Schemes are 

 constantly appearing under new names involving only old ideas long since found 

 worthless. The Committee has believed that it can render best service, not so much by 

 exploiting new timber preservatives or substitutes, as by developing the principles 

 controlling the successful use of all methods. 



