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The card index oî Experiment station littérature 



UNITED STATES DEPARTMENT OF AGRICULTURE. 



OFFICE OF EXPERIMENT STATIONS — Circular 47 (Rev.) 

 A. C. True, Director. 



It is the purpose of this circular to outline briefly the gênerai plan of the subject 

 index of experiment station literature regularly issued in card form by this Office, and 

 to state the conditions governing the distribution and sale of the index. 



The index at the présent time covers only the publications of the agricultural expe- 

 riment stations in the United States, Alaska, Hawaii and Porto-Rico. Of thèse publica- 

 tions the index includes ail regular, spécial, technical, and research bulletins and the 

 reports, but not such publications as circulars and press bulletins, except as thèse are 

 reprinted in the other publications mentioned. Publications of this Department and of State 

 boards or departments of agriculture are therefore not included. The index beglns with 

 the publications of the stations for the year 18S8, and is kept as nearly up to date as is 

 practicable. 



The index comprises thirteen primary divisions, as follows: (1) General sciences, 

 (2) air and water, (3) soils, (4) fertilizers, (5) plants, (6) foods, (7) animais, (S) entomo- 

 logy, (9) dairying, (10) technology, (11) agricultural engineering, (12) statistics, and (13) 

 mjsjcellaneous. Thèse subjects hâve been divided and subdivided only so far as seemed 

 necessary to facilitate référence to the individual entries of the index. Under gênerai sciences 

 are placed only such entries as relate to the gênerai principles of the various sciences 

 which lie at the foundation of expérimental investigations in agriculture. Under statistics 

 are included the entries relating to the organization, equipment, and gênerai opérations of 

 the stations. The other primary divisions provide for the articles relating more directly 

 to the agricultural and économie investigations. The plan of the index permits the addition 

 of référence to any literature relating to agriculture, and also affords a wide opportunity 

 for the extension of the index by individual students for their own spécial purposes. 



Each of the divisions, as a rule, contains entries for ail the important articles on 

 the subject. In some cases, however, an article, especially of a popular nature, may deal 

 with several subjects and be indexed only under the most important phase of the work. As 

 an illustration of this point, an article dealing with the use of pertilizers for field crops on 

 certain soils may appear under only one of the headings — Fertilizers, Field Crops, or Soils. 

 This has been necessary in order te keep the number of cards within reasonable limits. 

 Where the index, however, is used in its entirety, as planned, cross références lessen the 

 difficulty from this source. 



The divisions and subdivisions are arranged on a décimal System and are plainly 

 indicated by the use of division cards of diffe»rent colors. 



