CHEMICAL INDEXING: THE LITERATURE CHEMIST'S POINT O F VIEW* By NORMAN G. FISHER Central Research Department, E.1. du Pont d e Nemours and Co., Wilmington, Delaware
My assignment, according t o the p r o g r a m , is t o p r e s e n t l i t e r a t u r e c h e m i s t ' s point of view" about chemical indexing. L e t u s change the f i r s t word in the title s o that i t r e a d s , "A l i t e r a t u r e c h e m i s t ' s point of view" m y own. Not everyone with the label "literature chemist" will s u b s c r i b e t o m y opinions. T h e s e views s t e m f r o m a n association with chemical l i t e r a t u r e work f o r m o r e than 20 y e a r s i n a l a r g e organization emphasizing fund ament a1 r e s e a r c h in c h e m i s t r y . P e r s o n a l experience includes frequent u s e of chemical indexes, occasional design and construction of s m a l l - s c a l e specialpurpose indexes, and r e c e n t participation in a group effort t o exploit mechanical aids in the s e t - u p of a few indexes of m o d e s t s i z e . At the s t a r t of a d i s c o u r s e on p r o b l e m s in indexing, I think i t i s fitting to recognize how well off we c h e m i s t s a r e -- relatively. The a c cumulated r e c o r d of knowledge in many other subject disciplines is l e s s well organized and l e s s a c c e s s i b l e than i s o u r s . This is a tribute t o those who have labored f r o m e a r l i e r t i m e s t o provide the existing i n s t r u m e n t s we have f o r hunting among the r e c o r d s . I t u r n now f o r the look a t chemical indexing today, as I s e e i t . If we l i t e r a t u r e c h e m i s t s have nothing e l s e in common, we c e r t a i n l y d o s h a r e a vital i n t e r e s t in chemical indexes and the know-how of using them. Indexes a r e among the key tools in our workshops. P e r f o r m a n c e of our jobs depends on t h e m . Naturally we a r e e a g e r t o s e e any new developments that will aid u s in t h e s e jobs. The panel c h a i r m a n posed five questions a s a common f r a m e w o r k on which we panelists w e r e t o build our d i s c u s s i o n s . I do not believe t h e r e is any single s e t of a n s w e r s having equal validity f o r a l l i n t e r e s t e d p a r t i e s . E a c h instance of u s e f o r an index has a c e r t a i n individuality of purpose. E a c h index is built in anticipation of s e r v i n g s o m e recognized pur p o s e s . If t h e s e t u r n out t o be a poor m a t c h with the ad hoc purpose in an individual c a s e of d e s i r e d u s e , the u s e r i s likely t o consider the index a poor one. Stated m o r e simply, p e r h a p s , I m e a n t o s a y that our p u r p o s e s in attempting t o u s e indexes a r e subject t o variation through a wide range w h e r e a s m o s t indexes do not p o s s e s s c o m m e n s u r a t e flexibility of application. T o avoid the difficulties in the p h r a s i n g of really p r e c i s e a n s w e r s , I shall consider the questions in t e r m s of principles. Question 1 i s : what kinds of r e c o r d e d information w a r r a n t chemical indexing ? An index-user whose c o n c e r n is solely convenience t o himself m a y be tempted to
a n s w e r simply "All kinds.'' Most of u s u s e r s , however, recognize that indexes a r e not j u s t wished o r willed into being. A p r i c e has t o be paid. It includes a m e a s u r e of b r a i n s , effort, t i m e , and willingness of somebody t o produce the indexes we u s e . An index u s e r , occasionally t u r n e d index m a k e r , a p p r e c i a t e s what i t takes. I think we will be w i s e t o modify the a n s w e r "All kinds . ' I My choice f o r f i r s t r a n k in importance a s m a t e r i a l t o be indexed well is the f o r m a l r e c o r d of any new findings of chemical f a c t s . I m e a n t o distinguish factual f r o m conceptual o r i n t e r pretive information. This choice is founded on the p r e m i s e that the substance of factual i n f o r mation does not change with t i m e . On the cont r a r y , conceptual o r i n t e r p r e t i v e information, admittedly v e r y important to understanding and integration of f a c t s , has a n e p h e m e r a l quality. On a long t i m e s c a l e i t is subject t o change. With r e s p e c t t o value f o r indexing, I would r a n k i t below factual information. In l a s t place I would put the kinds of information that have only s h o r t - t e r m news value. H e r e I expect vigorous d i s a g r e e m e n t f r o m s o m e good friends whose p r i m a r y i n t e r e s t s a r e in the field of chemical economics -- a n example being those concerned with m a r k e t development of new c o m m e r c i a l c h e m i c a l s , o r the implications of a commodity p r i c e change on an industrial p r o c e s s operation. I should like t o i n t e r j e c t a plea t o the i n d e x e r s i n connection with the indexing of new factual information. The plea i s t o avoid basing any selection of i t e m s f3r d i s c a r d o r o m i s s i o n f r o m indexes on p e r s o n a l notions of relative insignificance o r unimportance. One frequently h e a r s the plaintive suggestion that o u r p r o b l e m s with a fast-growing l i t e r a t u r e would be e a s e d by s e p a r a t i o n and d i s c a r d of the "junk" f r o m the m o r e valuable m a t e r i a l . We can a l l sympathize with the motives behind this suggestion. But one p e r s o n ' s "junk" m a y s o likely be another's t r e a s u r e , and what i s u s e l e s s today may t u r n out t o be m o s t valuable in tomorrow's tomorrow. The unfolding r e c o r d of new c h e m i s t r y a p p e a r s i n various physical f o r m s . W e have books, pamphlets, j o u r n a l s , monographs, t h e s e s , encyclopedias, individual r e p o r t s , symposia p a p e r s , and s o on. I do not believe we a r e w a r ranted in placing any g r e a t e m p h a s i s on physical f o r m of documents in a t t e m p t s t o formulate guiding principles f o r selection of m a t e r i a l t o b e indexed. By this I m e a n i t would be unwise, f o r example, t o s a y that we should carefully index journal a r t i c l e s and not books, o r that we should
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'Presented at T h e American Chemical Society Meeting in N e w York, N. Y., September, 1957.
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have a s e t of selection r u l e s f o r indexing peculiar t o e i t h e r f o r m of document. T h e r e is no r e l i a b l e c o r r e l a t i o n between document f o r m and suitability f o r indexing. In my judgment, the principle s e t f o r t h e a r l i e r , of relating index worthiness to expected p e r m a n e n c e of the validity of information, provides m o r e useful guidance. I suggest it be applied in combination with one other important consideration. As an index u s e r , I d e e m it important that the document indexed have reasonable a c c e s s i b i l i t y . It i s f r u s t r a t i n g to be r e f e r r e d by an index t o a document to which one cannot gain a c c e s s a t a l l , o r not without g r e a t difficulty. This c o n s i d e r a tion i s m y rearson f o r being d i s s a t i s f i e d with the indexing of u n i v e r s i t y t h e s e s i f the t h e s e s a r e only available f o r inspection a t s o m e f a r distant l i b r a r y and sometirxes then only a f t e r a t i m e consuming c l e a r a n c e p r o c e d u r e involving a p provals by the author and his p r o f e s s o r . The s a m e consideration of a c c e s s i b i l i t y s o m e t i m e s m a y be helpful in the choice of whether t o put m a j o r indexing effort on the f o r m of new information r e c o r d e d f i r s t o r on s o m e r e p r o c e s s e d v e r s i o n such a s an a b s t r a c t , o r s t i l l l a t e r i n t i m e , an e n t r y in a review monog r a p h o r textbook. I feel s u r e that a c c e s s i b i l i t y of the companion a b s t r a c t s contributes t r e m e n dously t o the value of the Chemical A b s t r a c t s indexes. It i s i m p o s s i b l e , of c o u r s e , t o detach the a c c e s s i b i l i t y f a c t o r f r o m other i m p o r t a n t ones such a s comprehensive coverage and the convenience of a common language f o r all the information. At m y place of work, the r e s e a r c h r e c o r d indexed is the r e p o r t p r e p a r e d by the l a b o r a t o r y c h e m i s t , and not the notebooks f r o m which the r e p o r t i s distilled. T h e r e i s only the original copy of a notebook; t h e r e a r e many copies of the r e p o r t . Notebook antecedents of r e p o r t s a r e identifiable i f needed. Finally, one cannot a n s w e r Question 1 a s if t h i s question w e r e completely independent f r o m a l l o t h e r questions. The setting in which an index i s expected t o o p e r a t e , the p u r p o s e s it is expected t o s e r v e , the u s e r s and t h e i r n e e d s , a r e o r should be d e t e r m i n a n t s f o r e a c h index created. Q u e s t i o n 2 is: What kinds of questions should chemical indexes be designed t o a n s w e r ? Question? is: F o r what kinds of u s e r s should chemical indexes be d e s i g n e d ? I choose t o c o n s i d e r t h e s e questions t o gether b e c a u s e of t h e i r c l o s e i n t e r r e l a t i o n s h i p . T h e s e a r e possibly the m o s t i m p o r t a n t two questions among the five. F o r any p a r t i c u l a r index, d e t e r m i n a t i o n of the "right" a n s w e r s t o t h e s e questions and the d e g r e e of compliance with those a n s w e r s i n the design of the index a r e p r e r e q u i s i t e f o r utility. I mentioned e a r l i e r m y belief that it is i m p o s s i b l e t o develop p r e c i s e specifications f o r indexing that will be uniformly applicable f o r all index situations. It m a y be u s e f u l , however, t o comment on r e a l
c a s e s , s e l e c t e d purposely t o be r e p r e s e n t a t i v e of appreciably different situations. The indexing of Chemical A b s t r a c t s , I s u s p e c t , i s the l a r g e s t chemical index under taking anywhere, u n l e s s the Russians have a l a r g e r one. D r . B e r n i e r will d i s c u s s Chemical A b s t r a c t s indexing authoritatively, but I wish to consider s o m e of i t s a s p e c t s for convenience in illustrating points bearing on Questions 2 and 3 . It i s obvious that indexes a r e m u l t i - p u r p o s e indexes aimed a t serving the i n t e r e s t s of all kinds of c h e m i s t s . T o the extent that abilities, f a c i l i t i e s , and budget p e r m i t , I' feel s u r e that the staff would v e r y much like t o have t h e i r indexes responsive t o the full range of question types that a r e likely t o have appreciable frequency. It i s a f a i r a s staff sumption that s o m e people on the have given and do give study t o the p r o b l e m s of accommodating the indexes t o the s p e c t r a of demands made by index u s e r s . No doubt they l e a r n much f r o m volunteered c r i t i c i s m . I do not s e e , however, how t h e r e can be any confidence about knowing what u s e r s r e a l l y want in a comprehensive index without now and then making a c a n v a s s of a c r o s s - s e c t i o n of s u b s c r i b e r s . The r e s u l t s of such a project would but c e r t a i n l y be i n t e r e s t i n g , not only t o t o many o t h e r s . Having just made the point about c a n v a s s ing a c i r c l e of index u s e r s , i t would certainly be presumptuous of m e to s a y that I can i t e m i z e all the different s o r t s of questions that all fellow c h e m i s t s a r e likely to pose t o indexes. A l i t e r a t u r e c h e m i s t , however, i s in a s p e c i a l position t o know a little bit about s o m e q u e s tions asked by people other than himself. In much of his work he i s involved with other peoples' questions, often a s essentially an agent f o r o t h e r s in getting questions answered, and i n additional c a s e s a s advisor on l i t e r a t u r e consulting p r o b l e m s . Such p r o b l e m s a r e s u p posed t o be in his special province. On the b a s i s of such qualifications, I may speak about s o m e kinds of questions I know something about f r o m p e r s o n a l experience. A v e r y l a r g e fraction of questions asked, although subject to infinite variation i n the phrasing and in r e s p e c t t o locus in the domains of o u r knowledge, fifs roughly into a common p a t t e r n . F o r convenience I call t h e s e s i m p l e a d d r e s s questions. The a n s w e r sought, if i t e x i s t s , is usually an individual piece of i n f o r mation o r possibly a modest a s s e m b l y of a few s u c h p i e c e s , and one expects t o find the a n s w e r again, under a single a p p r o p r i a t e index label if t h e r e is one. This is the everyday stuff that the practicing c h e m i s t works with. Questions m a y p e r t a i n t o an individual compound o r e l e m e n t , p r o p e r t i e s a s s o c i a t e d therewith, a p a r ticular reaction, apparatus, a procedural method, a specified a u t h o r ' s contribution t o an identified subject i n t e r e s t , and s o on. Except
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Norman G. F i s h e r
f o r troubles associated with s h e e r magnitude of n u m b e r s , these questions a r e not difficult in principle for index t r e a t m e n t . A second type of question reflects the human t r a i t of aiding m e m o r y and thought through mental association o r c o r r e l a t i o n of i t e m s on the b a s i s of something in common. P e r h a p s I need only to mention a few expressions to i l l u s t r a t e my meaning: such, f o r example, a s " a r o m a t i c p r o p e r t i e s , I ' "negative groups , ' I "betaelimination," "volumetric methods ," "conjugated unsaturatitm." In the c a s e s of association of I mean the concepts a l r e a d y well recognized association is a l r e a d y recognized -- questions involving them m a y o r m a y not encounter dif ficulty in indexes. It depends on the specific question, on whether the association includes l a r g e o r s m a l l t e r r i t o r y , and on whether the existing l i t e r a t u r e on the subject i s voluminous. But c h e m i s t s a r e continually seeking and d i s covering new associations and relationships. Development and establishment of such new relationships frequently involves a hunt in the l i t e r a t u r e for comparison of a laboratory finding of the p r e s e n t with a possible ancestor o r analog. The kind of question that s e e k s t o validate o r elaborate a prospectively new a s sociation often i s confronted with r e a l difficulty in conventional indexes. Suppose a laboratory colleague comes t o u s with the alleged discovery of a new rea.ction of the olefinic bond. He wants to establish whether his reaction i s really new and, if it i s , he i s i n t e r e s t e d in whether the l i t e r a t u r e provides any information helpful t o guessing the likely breadth of application for his new reaction. Conventional indexes a r e not s e t up t o yield u s readily a complete catalog of reactions known f o r carbon-to-carbon double bonds. T h e r e f o r e , right at the beginning we a r e diverted f r o m a s t r a i g h t - c o u r s e approach to the d e s i r e d a n s w e r . We may have to be satisfied with an answer of lower s t a t u r e and modified complexion v e r s u s original intentions. The p r o c e s s of associating concepts may lead to questions of a higher o r d e r of complexity. Sometimes wanted information i s specified r a t h e r p r e c i s e l y in t e r m s of a confluence o r combination of s e v e r a l o r many c h a r a c t e r i s t i c a t t r i b u t e s . If we w e r e able t o u s e a plurality of the attributes simultaneously in the s e a r c h ing p r o c e s s , the d e s i r e d t a r g e t would be pinpointed accurately and the s e a r c h should be efficient. It i s exactly this kind of question, plus the need for flexibility in the formulation of the usable combinations, that has enhanced i n t e r e s t in the possibilities of some newer indexing techniques and devices. But that i s the t e r r i t o r y of l a t e r questions. Question 4 i s : What kinds of indexes a r e best suited, respectively, to the various types of chemical l i t e r a t u r e to be indexed? The functions of chemical indexes m a y be likened to those of guide-maps. A road map o r
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s t r e e t m a p is v e r y useful t o help one locate the position of individual highways. But suppose one is a highway landscape engineer who wishes to examine a sampling of highways where oak t r e e s have been planted a s p a r t of the beautification t r e a t m e n t . The conventional m a p s you and I obtain f r o m s e r v i c e stations a r e of little help t o the engineer f o r his o a k - t r e e question. The purpose of this simple example i s to r e emphasize the importance of a reasonable match between the capabilities of an index and i t s expected u s e s . It is quite appropriate that we should have different kinds of index tool for different kinds of problem. I shall now t r y to examine a few f a m i l i a r types of index with attention t o t h e i r capabilities and limitations. The conventional f o r m u l a index has many v i r t u e s . As a device f o r aiding quick and convenient access to information on individual chemical elements and compounds, it is p e r haps unequalled. The apparatus can be s i m p l e , the conventions of u s e a r e e a s i l y m a s t e r e d , s i z e and growth are not s e v e r e r e s t r i c t i o n s , the m a i n s t r u c t u r e is free f r o m the complexit i e s and v i c i s s i t u d e s of nomenclature, and t h e r e is no need f o r continual redesign t o keep one up-to-date. In s h o r t , the f o r m u l a index i s a nice, neat, sensible tool. But p l e a s e note what I s a i d it i s good f o r locating information about e l e m e n t s and compounds s o n e approach only, the kind and number of e l e m e n t s involved. At the c o s t of effort, time and ingenuity, one can work out ways t o a n s w e r a l i m i t e d range of g e n e r i c o r coordination-type questions by appropriate manipulation of s o m e l e t t e r and number c o m binations. But the f o r m u l a index i s a dull tool indeed, essentially u s e l e s s , for answering many types of question that c h e m i s t s ask. It i s even ineffective f o r handling s o m e chemical compositions that come c l o s e t o our concept of a compound. The field of polymers is an outstanding example. Another i s non-stoichiom e t r i c c r y s t a l l i n e "compounds" which a r e c u r r e n t l y i n prominence f r o m the rising tide of s o l i d - s t a t e studies. H e r e i n t e r e s t l i e s in component v a r i a t i o n s in the o r d e r of p a r t s p e r billion o r even lower. I t u r n t o Chemical A b s t r a c t s again for an example of the second type of index -- the dictionary style of subject indexing. This is a t p r e s e n t probably the m o s t widely used kind of a multi-purpose index. Dr. B e r n i e r undoubtedly will tell about i t s good points, in e x pectation of which, t i m e m a y be saved by jumping d i r e c t l y t o s o m e of the shortcomings that s e e m to m e important. The alphabetical index, a s exemplified by Chemical A b s t r a c t s , is s i m p l e in principle but becomes v e r y complicated i n such a l a r g e s c a l e application. It a l s o r e q u i r e s l a r g e abilit i e s of the u s e r f o r maximum effective u s e . He m u s t be a good s p e l l e r . Of c o u r s e he ought to
CKEMICAL INDEXING AND THE LITERATURE CHEMIST
be anyway. He m u s t have o r m u s t a c q u i r e a r e a l l y imposing vocabulary. He n e e d s t o be a n e a r - e x p e r t in chemical nomenclature. Chemical nomenclature h a s become h a r d p r e s s e d t o d e a l adequate1.y with the i n c r e a s i n g complexity of known f e a t u r e s of c h e m i c a l s t r u c t u r e . The r e s u l t of much l a b o r with nomenclature p r o b l e m s is an ever-growing l a b y r i n t h of carefully defined d e t a i l r u l e s and conventions t h a t become i n c r e a s i n g l y difficult f o r any single p e r s o n t o m a s t e r -- a t l e a s t in h i s s p a r e time. IS it not f a i r t o a s k what i s the f u t u r e of any indexing s y s t e m inextricably dependent on nomenclature ? I cite a s an example only b e c a u s e it i s widely known. The limitations of which I speak a r e i n h e r e n t , t.o a varying d e g r e e , i n the d i c tionary type of: chemical subject index i n g e n e r a l . Nomenclature f i g u r e s prominently i n another inherent limitation of the alphabetical index. An alphabetical index is an o r d e r e d l i n e a r a r r a y of l a b e l s u.nder which individual p i e c e s of information a r e d i s p e r s e d according t o t h e i r c o r r e s p o n d e n c e with the labels. This operation r e s u l t s in s c a t t e r i n g the component p a r t s of an original combi.nation i n a s o u r c e document. The combination itself m a y have been of meaningful i n t e r e s t i n its own right. E a c h one of the d i s p e r s e d p i e c e s is a key t o the combination, but any one key m a y be a v e r y popular one that f i t s into other com.binations too. If a s e a r c h e r a t t e m p t s t o make a b e t t e r a p p r o a c h t o his wanted combination by using two o r m o r e of t h e keys t o g e t h e r , by looking f o r a coordination of e n t r i e s under two o r m o r e of the index l a b e l s , he m a y find that he f a c e s a f o r m i d a b l e task. Too often it i s practica1l.y i m p o s s i b l e o r prohibitively time-consuming. A s i m i l a r s e a r c h i n g difficulty i s encountered when the objective is a bit dif f e r e n t . The s e a r c h e r m a y want t o find i n f o r m a tion on the b a s i s of a c e r t a i n c r i t e r i o n which i s subordinate t o a plurality of the index l a b e l s . An i l l u s t r a t i o n m a y be chosen that s i m u l t a n eously shows how nomenclature complications can o p e r a t e in this type of situation. Inherent in our nomenclature s y s t e m is t h e r e q u i r e m e n t of subordinating c e r t a i n s t r u c t u r a l f e a t u r e s t o o t h e r s in name building. Witness t h e Chemical A b s t r a c t s o r d e r - o f - p r e c e d e n c e of chief functions, not t o mention a l l the o t h e r functions p r e s u m a b l y of lower g r a d e . If the c r i t e r i a of a d e s i r e d s e a r c h e m p h a s i z e one of the lowo r d e r functions, o r still m o r e likely a combination of t h e m , the prospective m a t e r i a l m a y be indexed under l a b e l s a l l t h e way f r o m "A" t o "2." Incidentally it has become m y p r a c t i c e t o c a l l t h i s an A-to-Z s e a r c h situation. When we a t m y location r e c e i v e a r e q u e s t that a p p e a r s t o c a l l f o r one, o u r n o r m a l r e s p o n s e is t o advise the r e q u e s t e r that he attempt t o modify the r e q u e s t and s e t t l e f o r something less o r d i f f e r ent that is still useful. Punched c:ards have achieved a position of d e m o n s t r a t e d utility in connection with chemical
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indexing during the l a s t d e c a d e , approximately. Possibly the optimum l i m i t s of applicability f o r the punched c a r d have not yet been defined exactly, but a t l e a s t s o m e of the u s e s have been f a i r l y well established. A newcomer to the subject with intentions of using punched c a r d s i s well advised to investigate the substantial l i t e r a t u r e now available f o r guidance. In my view, the significant contributions of the punched c a r d a r e two: (a) providing a tool that expands our ability t o maneuver and manipulate index approaches to subject m a t t e r , (b) introducing the factor of mechanical a s s i s t a n c e in the physical operation of consulting the index. Results f r o m the l a t t e r m a y be r e a l i z e d in the f o r m o'f beneficial relief f r o m p u r e toil a n d / o r i n c r e a s e d speed of getting a n s w e r s f r o m an index. Our experience with manually s o r t a b l e edge-notched c a r d s has shown them t o be u s e ful in two general types of situation. F i r s t , in making l i t e r a t u r e s e a r c h e s that involve a s s e m bly of information in a subject field a s opposed to collecting all that i s known about a single i s s u e , we have found it helpful to a s s e m b l e the e x t r a c t e d information on punched c a r d f o r m s , usually not m o r e than one r e f e r e n c e p e r c a r d . The punching f e a t u r e i s used a s a help to a n a l y s i s , organization, and digest of the a s sembled m a t e r i a l . The indexing i s kept a s s i m p l e a s possible and i s custom-designed f o r e a c h p a r t i c u l a r c a s e . More often than not, this kind of application r e p r e s e n t s a o n e - t i m e u s e of the punched c a r d s , that i s , t h e i r functioii i s only to aid work-up of the m a t e r i a l . Our l i t e r a t u r e s e a r c h products a r e a l m o s t always i s s u e d in multi-copy r e p o r t f o r m . Otherwise, the s e t of punched c a r d s might have m o r e p e r manent value. The second g e n e r a l type of u s e for edgenotched c a r d s includes a considerable range of what I shall call special purpose indexes of m o d e r a t e s i z e . H e r e we wish t o exploit the ability of punched c a r d s to provide a multiplicity of index approaches t o subject m a t t e r that can be used in any combination s i m u l taneously. Such indexes a r e made with the expectation of continued u s e over a c o n s i d e r able period. At higher l e v e l s , the s i z e of the needed vocabulary and the number of c a r d s in a collection become important limitations on the convenient usefulness of edge-notched c a r d s f o r this application. The exact n u m e r i c a l values f o r the l i m i t s on both f a c t o r s v a r y f r o m c a s e t o c a s e . F r o m second-hand information, I understand that many c h e m i s t s u s e the edgenotched c a r d s extensively f o r personal collections of information in g r e a t v a r i e t y . My experience with machine-manipulated c a r d s i s m o r e l i m i t e d . We a r e using them for chemical indexing of l a b o r a t o r y r e s e a r c h r e p o r t s , a s r e p o r t e d a t the Miami meeting. T r a n s p o s e d t o a l a r g e r s c a l e of magnitudes,
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Norman G. F i s h e r
m y r e m a r k s about manually s o r t a b l e punched c a r d s a r e applicable t o machine c a r d s , I believe. It is p e r h a p s worth noting that r e s o r t to punched c a r d s a s an indexing tool demands a high o r d e r of s t r a i g h t thinking in index design and construction. Machine operation is a m a n i festation of applied m a t h e m a t i c s . The governing p r o g r a m that controls the p a t t e r n of moves m a d e by the machine m u s t be drafted with m a t h e m a t i c a l p r e c i s i o n if s a t i s f a c t o r y r e s u l t s a r e to be realized. Machines t h e m s e l v e s cannot d i s tinguish built-in e r r o r s of a n indexing s y s t e m s u c h as cam be detected e a s i l y by visual i n s p e c tion of an alphabetical index.
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Question 5 is: What new indexing t e c h niques a r e being developed and what a r e t h e i r potentialities ? I wish I knew t h e a n s w e r s t o t h i s two-part question, and especially the a n s w e r t o the s e c ond p a r t . My position thus far has been that of a n e x t r e m e l y i n t e r e s t e d r e a d e r , and o b s e r v e r , anxious to keep informed about newer developm e n t s and e a g e r to investigate new possibilities that look outstandingly good. At the moment a r a t h e r bewildering a r r a y of gadgetry, newly available, g i v e s exciting p r o m i s e .
