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T H E J0CRLV;AL OF IA’D U S T R I A L A N D E S G I S E E R I S G C H E M I S T R Y
EDITORIALS THE INDEX TO CHEMICAL LITERATURE
Under this title, the U. S. Patent Office has published a statement1 describing the work undertaken by the Classification Division, so as to enable rapid and complete searches to be made on any subject of chemical literature. This is a gigantic piece of work, embracing not merely patent literature, but practically all fields of chemical literature. Before the chemical card index was commenced, anything like a complete search of the literature was practically impossible, and the validity of chemical patents was more or less in doubt; for, after the most elaborate search possible was made, a five-line paragraph in the files of some little known chemical journal published in Japanese, Russian or other not readily understood language, would be sufficient if cited in court t o invalidate the granted patent. It will be several years before this card index is complete, although much assiduous work is being done on it. I n the meantime, enough has already been accomplished that anyone making a search on the literature of a chemical subject, can save much labor and time b y consulting the index of the Patent Office. It should be noted t h a t the index is accessible not only to the examiners of the Patent Office, but t o patent lawyers practising before the office, as well a s t o chemists and scientific workers all over the land. Hence, this card index is becoming a national monument to chemical literature. For those not living too far away, a visit to Washington t o consult the index may prove the shortest and cheapest way t o make a search in chemical literature. I t would be highly desirable, however, if duplicates of this index could be obtained for the more important libraries all over the country. I t is true t h a t copying this card index would be rather expensive, but there is no doubt that the enormous value of such a copy would be fully worth the expense. Why could not some of the libraries of the country work together and have several copies printed a t the same time, and thus distribute the cost of the task among themselves? It is interesting to quote from the report mentioned above :
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of the Chemical Society of London, the German abstract periodicals, Berichte and the Centralblatt, and other works of that character indexed up to date.’’ “Later when the American Chemical Society, in ~y);, cummenced the publication of its very complete set of sbstracts, it was determined to omit the periodicals in German and. a#.Jler foreign tongues. and retain in the card index only the yearly index volume of the Chemical Society of London in addition to the American abstracts.”
T h e above reference to the usefulness of the abstracts 01 the A m e r i c a n Chenaical Society would be decidedly wore satisfactory if i t were not accompanied by the jollowing statement: “The question has been raised whether the annual index of the Chemical Society of London is not duplicated by the work of the American abstractors to such a n extent as to render it useless to include both publications in the index.” “ I t is found upon comparing the published lists of the publications indexed by each set of abstracts as follows: Publications abstracted by the London Society ......................... IO1 Publications abstracted b y the American Society.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 516 Publications abstracted by the London Society not abstracted by the American. . . . 29 These 29 publications not covered by our American workers include the following viz.: German, 8 ; English, 1 2 ; Dutch, Swedish, and French, z each; and I each of Italian and Japanese. “Comparing 6 pages of the English Society Index of 1909 with the corresponding American work of the same year it is found that out of 256 articles and monographs indexed by the English workers, 159 of these articles were not in any way referred to in the American Society Abstracts.” “These two facts together seem to fully answer the question, and show the necessity of including both works in the index.”
May this criticism stimulate our American abstractors t o greater zeal and accuracy, aside from the fact t h a t many justified criticisms have been made that in some instances the abstracts are carelessly drawn up and give a very wrong idea of the originals. Various difficulties were encountered in outlining a general plan for the index. If chemical bodies each had but one instead of several names, and if in chemical literature one never met with bodies as yet unnamed and therefore referred t o by chemical formulas only, “ I n planning the chemical card index, since it was mani- then undoubtedly the dictionary plan pure and simple, festly impossible to index all chemical literature, it was de- with the names of the substances alphabetically cided to cover the nork of the past by- making a judicious selec- arranged and the references t o literature and patents tion of certain works of a general nature, such as the no-volume collected under their proper titles, would answer every work of Gmelin, the annual volumes of the Chemical Society of requirement, and would be, in fact, the only proper London, the 4-volume edition of Watts’ “Dictionary of Chem- system to use. Practically, however, most bodies istry,” Richter’s “Lexicon of Carbon Compounds,” and other known to chemists have a plurality of names, and the works of that character; by indexing these works the literature names approved and used in prior decades are generally of the past mould probably be as completely covered as it could not the names in highest repute nor in ordinary use be by any plan which the office had the force and means availto-day, nor is i t a t all sure t h a t the names now in use able for accomplishing.” “ F o r the future it was proposed to keep the abstract journals will in most or even in many cases remain in use in years t o come. 1 Appendix K of the Report of the Investigation of the U. S. Patent Office, by the Presldent’s Commission on Economy and Efficiency, DecemWhere a chemical compound has several names (asber, 1912 House of Representatives, 62d Congress, 3d Session, Document indeed is usually the case), were i t possible to decic? No. 1110
now (which perhaps might be done) which one of them is, on good scientific grounds, the most appropriate for index purposes in view of present knowledge, and further (which of course could not be done), could one be assured t h a t such name would remain the approved name for all future time. such title could, without hesitation, be now adopted as the indexing title, under which all references to literature or patents could be entered, and all other titles and names crossreferenced into i t ; but while this might be done now in certain cases, which and how many of these names now used and approved will remain in use in years t o come is something t h a t no one can a t present determine. Evidently the dictionary plan, unmodified, was not the best. and some better system had to be devised not open to these objections. The system adopted was based on the chemical formula. I n establishing for the Patent Office a card index to chemical literature, i t was therefore decided t o use, as a n indexing basis, the kind and number of the component atoms of a chemical compound, these being its most unvarying characteristics, being subject only t o errors of chemical analysis, and being, therefore, the most stable and unchanging basis for any scheme for the indexing and digesting of chemical literature: a conclusion reached a t about the same time independently by- Richter, as illustrated in his since published Lexicon der Kohlenstoff-Verbindungen, and by other later workers in this field. the Patent Office system differing from that of Richter in being simpler and of more general application. It was found that the simplest, most certain, and most direct system, was to rewrite the so-called empirical chemical formula in a particular manner, t h a t is to say, to write the atoms in the alphabetical order of their chemical symbols, upon library catalogue cards of standard size, and place these cards, arranged in alphabetical order, in standard library cases. For example, take the following chemical compounds : . Dinitrobutane (CH,) ,C,H,( NO,) ? . . . . . , . . Isopropylic nitrite Potassium acetate Methyl chloride Copper arsenite Rewriting them and arranging them alphabetically by formulas instead of titles, they are: As,CuO,. . , , . . . . . . , . . . . . , . . . . . Copper arsenite , . . . . . . . Methyl chloride C,H,KO, . . . . . . . . . . . Potassium acetate Isopropylic nitrite . . . . . . . . Dinitrobutane
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I t should be noted, however, that the compounds containing carbon and hydrogen, and broadly included in the domain of organic chemistry, constitute so large and important a class that it is fully justifiable to depart slightly from the strictly alphabetical arrangement of chemical symbols, and write C always first and H accompanying C always second, in order to bring more closely together in the index bodies more or less closely related in chemical and physical properties. I n practice, therefore, the following general rule has been followed in compiling the chemical card index of the Patent Office: Reject water of crystallization and rewrite the empirical formula in the alphabetical order of the chemical symbols, except that in carbon compounds, C is to be written first and H second. Follow this rewritten formula with the constitutional formula, when given, adding the water of crystallization, if any, but arrange the cards alphabetically by the rewritten formula. The reason for disregarding water of crystallization may be illustrated as follows: The three bodies, Na,SO, or anhydrous sodium sulfate, Na,SO, 1 o H , 0 or Glauber's salt, and the heptahydrated salt, 7H,O, are in this way indexed under the Na,SO, same indexing formula, Na,O,S, and are thereby brought together, as they should be, for in solution they are chemically identical. If, on the other hand, water of crystallization were taken into account for indexing purposes, the corresponding indexing formulas would become Na,O,S, H,,Na,O,,S, and H,,Na,O,,S, respectively, and these three practically identical bodies would, in consequence, be widely separated in the index, which result would evidently be a very undesirable one. The index was commenced and has been continued on the library-card catalogue plan, using the regular standard card, size b y r z l / , centimeters, or approximately 3 by 5 inches, without rulings except a single colored horizontal line 3 / / , of a n inch below the top of the card-this for typewritten cards and cards upon which printed matter cut from books and periodicals is pasted. -4 limited use has also been made of cards having ruled lines, where for certain reasons the cards are written by hand. I believe it would be very desirable to have a n exchange of opinions on this subject in the correspondence column of this journal. I t is our duty to assist by any helpful suggestions possible, the good work which is now being performed by the Washington Patent Office. I,. H . B A E K E L A K D
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ORIGINAL PAPERS
PRELIMINARY REPORT UPON A PRACTICAL ACCELERATED TEST FOR PAINTS AND VARNISHES' BY A. M. XUCKENFUSS
There being comparatively few constants in nature, 1 Author's abstract of paper presented at the Milwaukee meeting of the American Chemical Society, Harch 25-28, 1913.
it follows t h a t most materials are continually changing their properties with use, though a t widely varying rates. I n the case of paints, varnishes and some other materials affected by exposure to atmospheric agencies of destruction, this change of properties is quite rapid a t first and continues generally a t a di-
