INVERTED COORDINATE INDEXFOR X-RAYDIFFRACTION known as STAR. The periodical published literature is covered in AIAA’s International Aerospace Abstracts. Both S T A R and ZAA are issued semimonthly on alternate weeks. Each issue is arranged in two major sections: the first presents informative abstracts; the second includes the subject, corporate source, author, and report number indexes. I n addition to the indexes in each semimonthly issue, cumulative indexles are distributed which integrate and cumulate the indexes quarterly, semiannually, and annually. Both S T A R and I A A follow the same format, the same abstracting and indexing techniques, and the same indexing terms t o provide the individual user with compatible bench tools. I n addition t o these two compatible services, KASA also assists in the support of the Aerospace Medicine Bibliography Project a t the Library of Congress, the publication of abstracts in the Journal of Aerospace Medicine. and the relevant abstracts in Meteorological and Geoastrophysical Abstracts. The interest here is in complementing or supplementing the aerospace coverage with abstracting and indexing in depth by experts in the subject matter field itself-the “identifiable area” approach. Prior to each issuance of S T A R , the NASA system provides for automatic distribution of the reports covered in the journal to local centers where they can be available to the individual user as he identifies them in the an-
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nouncement journal. The distribution is either in macroform (that is, full-sized printed copies) for reports published by NASA, and in microform for KASA and non-NASA reports covered, except those subject to reproduction limitations. T h e next step is the forthcoming implementation and evaluation within the NASA complex of a system for selectively disseminating report literature. This involves the matching of profiles of user needs and interests with profiles of report content. Such a system does not presume to “prepackage” what information it will provide, it does not attempt to impose a classification or indexing system beyond what is needed by the information service to retrieve the documents in its collections, and it is primarily determined by the characteristics of the user. Certainly much of what has been described in this paper is not unique. What is regarded as significant, however, is that the whole system is deliberately geared to current awareness and local access by the individual scientist and engineer. The emphasis is on helping the individual user to identify what is relevant to him so that he may project and extrapolate as befits the subject matter expert. And this is appropriate to servicing such an area as Bioastronautics. An information service must gear itself to the characteristics of the area to be served lest it find itself in the same relation to its users as science fiction has to the products of sober research.
Searching X-Ray Diffraction Powder Data with an Inverted Coordinate Index* By F. W. MATTHEWS Central Research Laboratory, C a n a d i a n Industries. Ltd., McMasterville, Quebec, C a n a d a Received April 22, 1963
The X-ray diffraction. powder method of identification of solid substances has been described as a fingerprint method in that each substance in the solid state gives a unique pattern. As with the fingerprint method of identification, it depends on matching the pattern of the unknown with established data. This use of the powder diffraction pattern was clearly envisaged by Hull. who in the Journal of the .4merican Chemical Societ?, for the year 1919’” described this use of the pattern with examples of how it could be emploved. However. the method was not applied for lack of data which was in part due to the lack of hardware t o record the patterns conveniently. I t took almost 20 years to overcome these hurdles. The method took on practical importance with the publication by Hanawalt and Rinn9 of the Dow Chemical Company in 19%. These authors realized that application of the 1’re.entc~rl l x , l n t t ~t h e I l l \ i c i o n 01 (’hemic4 liiteriitiire. l i ? n d .A( h \ ~ r i o n i I Xleetini. ( 11,. K . I . \c,nC.,nl~er I?. 191;2
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