TIME-LAG in CHEMICAL LITERATURE M. G. MELLON Purdue University, Lafqette, Indiana
Chemistry i s a science undergoing rapid, changes as a factor should be considered in using these sources of inresult of the accumulation each year of many new facts formation. To designate this factor the expression "timeand of the proposal of new interpretations to account for lag" i s used here. I t refers either to the lapse of time beboth old and new facts. To kee9 in touch with these tween the date of receiting a manuscripl for a proposed developments and to take adwantage of the wast store of publication and its dale of issue, or, muchmorefrequently, data already collected, the chemGt relies largely upon the to the degree to which a book, for example, i s out-ofdate various kinds of auailable chemical publications. He does with respect both to the material in i t and to that whuh it not always recognize, howewer, that a n important temporal does not contain.
I
N THE original or primary sources of chemical literature, consisting of periodicals, institutional publications, patents, and miscellaneous contribu tions, there is, in general, reasonably satisfactory efficiency in getting the published material from the producer to the consumer. While the results of many researches undoubtedly remain unannounced for years for one reason or another, once the manuscript for a paper or a bulletin or the specifications for a patent have been accepted, publication usually follows relatively soon. Some delay is unavoidable, especially in annual publications like the proceedings of the various state academies. In monthly periodicals there is considerable variation, some articles appearing in less than a month after being submitted, while others are delayed a year or more. An inspection of current issues of several of the best-known periodicals shows much less time-lag in certain foreign publications than in our own. Probably the extreme cases of time-lag in this group are encountered in those institutional publications which are essentially statistical in nature, such as Mineral Resources and the different reports from the Bureau of the Census. The former may he two years late. The latter varies from some months for mimeographed intercensal reports to ten years for the decennial report of the census of the United States. The user of these primary sources may then usually expect, in so far as he is able to read them and with the exceptions noted, to keep currently informed of the reported advances in the field. Unfortunately, unless one is approaching in his chemical interests that ultimate degree of specialization represented by the individual who knows all there is to know about nothing, he finds himself overwhelmed by the tremendous annual accumulation of publications of the kind mentioned above. Chemical Abstracts' recent list of periodicals abstracted includes 1996 titles. During 1931 there was an average of more than 1000 patents issued each week in the United States, of which 25 per cent. are estimated to be of chemical interest. With this situation prevailing, it is frequently most efficient to seek desired chemical data in secondary sources, that is, those publications which serve fnndamentally as collecting, classifying, and organizing agencies. They index the material of the primary sources and put it in a form more readily available for use. Of these sources the most important are periodicals, such as abstracting journals, indexing serials and review serials, and general works of reference. Because of our dependence upon such publications, we are much concerned with the time-lag which intervenes between the date of publication of data in some original source and their later appearance in the several possible secondary sources. This time-lag becomes most striking in the larger works of reference or treatises. That it is not adequately appreciated would seem to be indicated by the reported consideration by British and American chemists during the World War of the feasibility of issuing in the English language the third edition of Beilstein's "Handbuch der organischen Chemie," a
work much of which was a t that time nearly twenty years old. The too-general lack of skepticism regarding the reliability of such sources, as regards their relation to current information, seems to justify directing attention to the present situation. It becomes a matter of understanding the process involved and of adjusting ourselves to the existing situation, for the possibility of marked improvement seems unpromising, a t least until we advance to a social and political status in science less nationalistic and more cooperative. The time-lag in secondary periodicals varies widely for the three different types. On the average, it is undoubtedly least in the case of abstracting journals. No one with a realization of the huge problem involved can have anything but admiration for the fine way in which our own Chemical Abstracts is handled. It is literally a task of searching the scientific and technical puhlications of the world to find all the new items of chemical interest. The promptness with which an abstract of each of these appears depends principally upon the availability of the publication itself and upon the quickness of response of the designated abstractor on receiving the publication. Mr. E. J. Crane, editor of Chemical Abstracts, has estimated that an abstract will appear, on the average, after the original puhlication is available in this country, in not less than a month and usually not much more than two months. Abstracts of advance proof or of obscure puhlications are exceptions in their respective directions. An occasional case arises also in which a publication does not reach an abstractor promptly. Indexing serials show a much wider variation than abstracting journals. The Agricultural Index, for example, is issued each month and is probably about as nearly current as possible. Annual publications, such as Engineering Index, obviously cannot be as nearly up-to-date for all items published during a given year. Probably the best example of time-lag in this kind of publication is furnished by the "International Catalogue of Scientific Literature." As far as the writer is aware, the subject index for chemistry for the period 18001900 has not yet appeared in 1933. Review serials, usually being issued annually, contain unavoidably more or less information a t least a year old when compiled. To this must be added whatever time is required to take the material through the process of publication. The English serials, "Annual Reports of the Chemical Society" and "Applied Chemistry Reports," for 1931 were not available until late in 1932. Time-lag becomes probably most disconcerting in our larger works of reference, such as formula indexes and treatises. Aiming to present either a complete list of all known compounds or a comprehensive survey of an entire field of chemistry, the preparation of these publications in a form even approximately up-to-date represents probably the most difficulttask in the realm of chemical literature. Compiling, checking, evaluating, and arranging the material requires years, even with a group of workers. In such work a date must be
JOURNAL OF
CHEMICAL EDUCATION
TABLE l.-I~ono*mc R ~ s e a a W ~ cm~x s
Porrnl and Baud Aetinivm Alumioum Antimony Argon Arsenic Barium Beryllium Bi~muth Boron Bromine Cadmium C.leium Carbon Cerium cesium Chlorine Chromium Cobalt Columbium copper Dyspra3ium Erbivm Europium Fluorine Gadolinium Gallium Germanium Gold Hafnium Helium Holmium Hydrogen 1iiinium Indium Iodine Iridium Iron Krypton Lmnthanum Lead Lithium Lutetium Mhgnerivm Manganese Masurium Mercury Molybdenum Neodymium Neon Nickel Nitrogen osmium 0.W" Paliadlum Phosphorus Platinum Polonium Potasrium ha~eodymium Protoactinium Radium Radon Rhenium Rhodium Rubidium Ruthenium samarium Scandium Selenium Silicon Silver Sodium strontium Sulfur Tantalum Tellurium Terbium Thallium Thorium Thulium Tin Titanium Tungsten uranium Vanadium xenon Ytterbium yttrium zinc zirconium No. 85 No. 87 Ammonium rompovndr
No. 40 NO. 35 No. 18 No. 1 (26) No. 17 No. 30 No. 26 (301 No. 19 (27) No. 13 (26) No. 7 (31) No. 33 (25) No. 28 No. 14 No. 39 No. 25 No. 6 (27) No. 62 N a 58 (3092) No. 49 No. 60 No. 39 NO. 39 NO. 39 No. 5 (26) NO. 39 No. 36 No. 46 (31) No. 62 NO. 43 No. 1 (26) NO. 39 No. 2 (27) No. 38 NO. 37 No. 8 (31) No. 67 No. 59 (29-32) No. 1 (26) No. 39 No. 47 No. 20 (27) NO.39 No. 27 No. 66 NO. 60 NO.34 No. 63 No. 39 No. 1 (26) NO. 57 NO. 4 No. 66 NO. 3 NO. 65 No. 16 No. 68 NO.12 NO. 22 No. 39 No. 51 No. 31 (28) No. 1 (26) No. 70 No. 64 No. 24 No. 63 NO. 39 NO. 39 NO. 10 No. 15 No. 61 No. 21 (28) No. 29 (311 NO. 9 No. 60 NO. 11 No. 39 No. 38 NO. 44 No. 39 No. 46 No. 41 NO. 54 NO. 55 No. 48 No. 1 (26) No. 39 NO. 39 No. 32 (24) No. 42
..... No. 23
111, 1 (06) 111, 3 (07) IV, 3, 1 (28) 111. 3 (07) 11, 2 (05) 11. 2 (05) 111, 3 (07) 111, 1 (06) IV, 2 (13) 11, 2 (13) 11, 2 (05) 111. 2 (09) 111, 1 (06) 11. 1 108) IV. 2 (13) IV, 1, I1 (21) 111. 3 (07) 11. 1 (081 111. 1 (06) 111, 1 (061 111, 1 (06) IV. 2 (13) 111, 1 (06) Ill. 1 (06) 111, 2 (09) 11. 1 (08) IV. 3, 1 (28) 111. 1 (06) 11. 1 (08) 111, 1 (06) IV, 2 (13) IV. 3 . 2 (3& IV, 3, 1 (28) Ill. 1 (06) 111, 2 (09) 11. 1 (08) 11, 2 (05) IV, 2 (13) 11, 2 (06) IV, 1, I1 (21) 111. 1 (06) IV, 3. 1 (28) 111. 3 (07) IV. 1. 1 (27) 111, 3 (071 IV. 1, 1 (27) 11. 1 (08) 111, 1 (06) 11. 2 (06) IV, 3, l ( 2 8 )
111, 1 (06) 111. 1 (06) IV, 1, 1 (27) 111. 2 (091 11, 1 (081 11, 1 108) 11, 2 (05) IV, 1, 1 (271 111, 3 (07) IV, 1, 1 (27) 111, l ( 0 6 ) 111, l ( 0 6 ) 111, 2 (09) 111, 1 (061 111. 2 (09) 111, 2 (091 IV, 1, 11 (21) IV, 1, I1 (21) 111. 3 (07) IV. 3, I (28) 111. 1 (06) 111, l(O6) 11, 2 (05) I l l , 2 (09)
VI VII IV XI1 111 VI VII T" ..
IV 1 (31) VII VI V (32) VIII VT i i31) X X IV VIlI VIII VlII VIll 1 (31) VIII VII v (32) VIll V (32) XI1 VIII 1 (31) VIII VII 1 (31) XI (32) IX XI I Vlll IX VI VIII VII IX --IX VlII XI (32) VIII XI1
"
I11 XI (32) I (31) XI (321 111 XI (32) VI VI VIlI VI VI XI1 IX XI (321 VI XI (32) VIII VIII
,,
G'(32) VlII VI VI 11 IV 11 VIII IX XI (321 VlII IX V (32) X I (32) X I (32) TV
set after which new contributions cannot be accepted because of the necessity of starting those already assembled through the process of printing. By the time the latter procedure is accomplished more years have elapsed. For "International Critical Tables" all data were collected up to 1924, but the first volume was not published until 1926and 1930 arrived before the seventh (final) volume appeared. In this particular case we have a supplementing publication in the French "Tables Annuelles . . " but its time-lag reaches several years for some volumes. As further examples we may consider the descriptive type of treatise in the general fields of organic and inorganic chemistry. The monumental compilation for the former field is Beilstein's "Handbuch der organischen Chemie," the fourth edition of which is now being issued by the Deutsche chemische Gesellschaft. The mainvolumes include material to 1910, the first of which appeared in 1918 and the sixteenth (latest) in 1933. Probably the most numerous groups of compounds have now been included, but the first sixteen volumes have not covered half of the projected 4877 classes of compounds. For compounds not yet covered in the new edition the third edition contains nothing later than 1899-1903, making i t more or less obsolete now because of the phenomenal progress in organic chemistry since 1900. Already (February, 1933) supplementary volumes have appeared for the first ten original volumes of the new edition. It should be noted, however, that these contain information only to 1920. For later facts the searcher must be his own compiler. In the inorganic field we have as yet no dominant treatise such as Beilstein's for organic compounds. Since several sources of this type are more or less generally used, a tabular summary is given (p. 286) showing which volume of each set contains informatiou about each element and also the dates of publication of each volume. This may serve as an aid in noting quickly whether desired information for a given element may be found in any of the sets, the approximate degree to which i t is up-to-date, and the volume in which it is located. One of the sets is bound without any indication of the elements covered in each volume and a second indicates only the periodic groups covered. The following sets have been examined as being the most important a t the present time: Hoffmann, "Lexikon der anorganischen Verbindungen"; the new eighth edition of Gmelin, "Handbuch der anorganischen Chemie"; Mellor, "Comprehensive Treatise on Inorganic and Theoretical Chemistry"; Friend, "Textbook of Inorganic Chemistry"; Abegg, Auerbach, and Koppel, "Handbuch der anorganischen Chemie"; and Pascal and Baud, "Traite de Chimie Minerale," just starting to appear. All the announced forthcoming volumes of the sets of Gmelin and of Pascal and Baud
.
* r'riend'n treatire include. four volumes not listed in the table-x eompoundr.
have been listed, the absence of dates showing the ones not yet available. Attention is directed in Table l * to two examples of time-lag only. Boron is discussed in four of the treatises, the dates of which range from 1906 to 1926. Until 1933 the elements of the platinum group were discussed in one treatise only and it appeared in 1922. Hoffmann's formula index is stated to contain nothing later than April, 1909. The situation mentioned above for the general fields of organic and inorganic chemistry is similar to that existing in treatises for the more specialized fields, such as analytical chemistry, biochemistry, experimental methods, and others. Wbat has been stated about treatises may be applied also to encyclopzdias, as i t is no less difficult to keep them up-to-date. Of the various kinds of publications available, monographs and textbooks remain for consideration. Although diering somewhat in nature, one may deal with them jointly for the present purpose. In general, they are reasonably up-to-date when published. All too often, however, users fail to note in a given book the date of publication or of copyright, as given on the title page or on the back of it, respectively. The information must be open to question after that date, and in addition time should be allowed for compiling and printing the material. Because the author's field is likely to be somewhat more limited and because he is more closely associated with all the developments in it, it is believed that information in monographs may be more dependable a t the time of publication than that in textbooks. It is not uncommon to find wrong or misleading statements, particularly concerning commercial practices and products, in late editions of the latter works, a situation doubtless attributable in many cases to non-appreciation of the time-lag of sources from which supposed facts were taken. In conclusion, the following points may be stated concerning the time-lag of information contained in the various kinds of chemical publications: 1. It is found in all publications to a greater or less degree. 2. In primary sources, such as periodicals, institutional publications, patents, and dissertations and manufacturer's technical bulletins, i t is usually relatively small. 3. In secondary sources, such as abstracting journals, indexing serials, review serials, and general works of reference, its magnitude is much more significant, reaching not infrequently in treatises values of five to thirty or more years. 4. Its occurrence seems a t present more or less unavoidable, necessitating the recognition of its existence and the regulation to it of our use of the literature.
(28) on metal smmines, and XI, (28). XIn (30). X l m (
) on the organometallie
