annotations in the bibliography. Once a desirable patent has been found 

 through inspection of the indexes or annotations, the other keywords for 

 the patent may be used as guides to further searching in the subject in- 

 dex. 



If information is needed on patents for floating breakwaters, for 

 example, two approaches may be taken. In the first case, if no numbers 

 for patents on floating breakwaters are known, the list of keyword defi- 

 nitions must be used to find at least one applicable keyword such as 

 "Breakwater, floating." Next, the list of patents referenced to that 

 keyword is located in a volume, as shown in Figure 11 for Volume III. 

 Inspection of Figure 11 reveals that some of the patents have "Floating 

 Breakwater" or something similar for a title and have only "Breakwater, 

 floating" as a keyword. For that type of patent, exemplified by patent 

 .3,991,576, the determination of the usefulness of the patent will require 

 examination of the bibliography annotation or of the patent itself. The 

 annotation for patent 3,991,576 is presented at the top of Figure 13 for 

 comparison with the subject index information listed in Figure 11 and 

 with the front page of the patent shown in Figure 1. In the second case, 

 if the number for a floating breakwater patent is known and can be found 

 in a title list, as was demonstrated for patent 3,991,576, then keywords 

 can be taken directly from the patent's annotation and used for searching 

 in the subject index with the confidence that the keywords apply to the 

 type of patents desired. 



Combinations of keywords may be used to identify distinct types of 

 patents in the subject indexes. If patents on methods of repairing wood 

 piles are desired, the keywords "Pile, wood" and "Structure repair" can 

 be used together to pick out those patents. Figure 12 includes the list 

 of patents referenced to "Pile, wood" in Volume I. Notice that most of 

 the titles, like "Posting Piling," do not mention the type of piling 

 involved in the patent. If methods of replacing a section of pile with 

 concrete are desired, look for the keyword "Concrete form." Patent 

 3,410,097, with its annotation illustrated at the bottom of Figure 4, is 

 an example. For methods of joining wood replacement sections to existing 

 piles, look for "Pile section connection" in the absence of keywords 

 mentioning concrete or steel. Patent 3,307,362, annotated at the bottom 

 of Figure 14, is an example of a patent with this combination of keywords. 

 Successful use of combinations of keywords requires close inspection of 

 the keyword definitions and of the keywords assigned to patents of known 

 value, plus experience in using the subject index. 



Searches for patents issued before 1967 or after 1976 can be aided 

 by the use of the classification information in the annotations. For a 

 particular coastal engineering topic, classification codes corresponding 

 to the topic or a keyword might be found by using the methods outlined 

 above to select related patents in the CERC collection, then recording 

 the classification codes common to all or most of the chosen patents. 

 As discussed previously, the classification codes or lists of patents 

 classified under the codes may be used as a guide to searching a patent 



