collection. This method cannot be used if the patents in the CERC col- 

 lection have been reclassified since they were issued. For instance, in 

 January 1979, the class code for "Hydraulic and Earth Engineering," the 

 class containing most shore protection and harbor structures, was changed 

 from 61 to 405 with corresponding changes in all of the subclass codes. 

 Table 4 gives all the new codes for the class. Currently, all of the 

 patents in the coastal engineering collection assigned class code 61 

 would be found in a library collection filed under class code 405 with 

 their subclass codes altered according to the differences between Figure 

 2 and Table 4. 



VII. SUMMARY 



Patents contain information valuable to designers, inventors, and 

 researchers working in the coastal engineering field, but the size and 

 complexity of the Patent Office collection have hindered the widespread 

 use of patents as reference sources. The CERC patent collection and its 

 search aids make a part of the Patent Office collection more accessible 

 to technical personnel. The search aids include: 



1. The patent number and title lists which are used to determine 

 whether a patent is in the collection; 



2. the subject indexes which are used to identify patents involving 

 specific topics; 



3. the detailed set of keyword definitions which describe how topics 

 are grouped together in the subject indexes; 



4. the annotations which present information on the invention, 

 inventor, assignee, application and patent documents, classification 

 codes and keywords; and 



5. the instructions on locating and examining copies of patents. 



In some cases the search aids may be used to link the keywords of the 

 CERC collection to the classification codes of the Patent Office collec- 

 tion, simplifying the identification of useful patents issued outside the 

 time period covered by the CERC collection and improving the usefulness 

 of the whole patent collection. 



44 



