CRANV1P1 Formation of Index Languages chapter Cyril Cleverdon Jack Mills Michael Keen Cranfield An investigation supported by a grant to Aslib by the National Science Foundation. Use, reproduction, or publication, in whole or in part, is permitted for any purpose of the United States Government. -79 - Class No. Afterbody, Conical Base ,Cylinder ,Cylindrical Drag Surface ,Truncated Vehicle, Conical (etc.) D6 D5 Base Afterbody, Conical Bleed ,Flat Forward attitude (etc.) TI6 K61 C one Cone, Blunt Nose , Blunted , Circular Cylinder Cylinder Bodies (etc.) H55 H76 H76 Conical Afterbody Vehicle A57 Base Afterbody C99 Camber W33 (etc.) It can be seen that each concept appeared as many times as it had distinct words. 5o the first concept above appeared in three different contexts - that of Afterbody, of Base and of Conical. The class number appeared after the direct form of the concept. The index served the obvious purpose of a key to location besides its other major purpose - thai of indicating all the different contexts in which a given term had appeared in the schedules. One aspect of this second function, the capacity to reveal other generic hierarchical relatienships, was discussed above. But this was only one kind of context revealed. In the example above, Afterbody surface, Base bleed, Base forward attitude, etc. reflect non-generic relations. The index therefore acted as a valuable supplement to the schedules proper in displaying thes[OCRerr] relations. The major display of these was, of course, by the subordination of a thing's categories to that thing. But these would not necessarily exhaust the non-generic relations, and the A/Z inde[OCRerr] not merely supplied further relations, but could lead the question pro- grammer back into the systematic order to explore further categories, if necessary. For example, examining the entries adjacent to Heat transfer leads to Heat sustaining leading edge (subordinate to Leading edge), to Heat transfer at the wall (subordinated to Surfaces and Walls, where related concepts such as Constant wall temperature and , Wall temperature gradient are found) and to Heated air (subordinated to Air, where related concepts such "as High temperature air and Dissociated air are found). Many of these other concepts do not contain the term 'Heat' or its variants and might not have been picked up had purely alphabetical considerations governed the search. A third major function served by the rotated A/7. index was to provide a recall device based on the ,accidental' alphabetical juxtaposition of concepts eajoying a limite('.