January 6, 1922] 



SCIENCE 



Simpliflcation and deliuiteness of purpose 

 give direction to the making of records and 

 the gathering of data. All experimental in- 

 quiry turns upon securing proof which is both 

 accurate and adequate to the purpose. The 

 method of science is the process of securing 

 accuracy and precision in purposefvil observa- 

 tion, and the interpretation of the product. 

 As has been said, it is "only a perfected appli- 

 cation of our human resources of observation 

 and reflection." 



The method is not a fixed thing but is con- 

 tinually changing as progress makes iDossible. 

 Science strives constantly after new ways of 

 acquiring and proving facts which would other- 

 wise not be known or but imperfectly so, and 

 at the same time eliminating the personal 

 factor. Apparatus and appliances are de- 

 signed primarily to make possible the taking 

 of observations which would otherwise not be 

 feasible, or with equal accuracy. They there- 

 fore enlarge the field of observation and in- 

 crease precision. 



This apjDlies of course to facilities and 

 methods for agricultural inquiry such as field 

 plats and cylinders, feeding appliances, special 

 apparatus and other means for securing experi- 

 mental data; and there is the same need of 

 critical examination of these from time to time 

 that there is of other facilities, to determine 

 whether they are supplying proof which is 

 accurate and sufficient, or to assess correctly 

 what can and what can not be shown by such 

 methods. 



The question is forcing itself upon the minds 

 of many as to the adequacy of certain types of 

 field experiments, as ordinarily conducted, to 

 answer fundamental questions in plant nutri- 

 tion and soil management. Large reliance has 

 been placed on such experiments in the past, 

 and data have been accumulated from them 

 over long periods. The oldest series of fer- 

 tilizer and rotation plats in this country runs 

 back over forty years ; several others have been 

 under way from twenty-five to thirty-five 

 years. One station has some two thousand 

 plats. 



These experiments have brought highly 

 important practical results, and have marked 



a definite step in agricultural inquiry. They 

 have furnished a rich background of material 

 and suggestion for more definitely directed 

 studies. The question is whether they have 

 reached their maximum and how far they are 

 to be depended upon in making further ad- 

 vances. 



It is now realized that many of these experi- 

 ments contain inherent difiiculties dating back 

 to their beginning, which introduce a strong 

 element of doubt in interpreting results. For 

 one thing, most of the published reports fail 

 to describe the soil except in the most general 

 way, and lack information as to the condition 

 and previous treatment of the field, indications 

 of irregularity, etc. Again, the number of 

 cheek plats is usually too small, and the same 

 is true of the amount of replication of treat- 

 ment. This may account for the difi'erent 

 interpretations made by different persons from 

 the same series of experiments. In few cases 

 has the necessary number of checks and dupli- 

 cates been worked out mathematically for such 

 experiments, and where there is considerable 

 variation in different parts of a field, averages 

 may furnish a doubtful basis for measuring the 

 effect of treatments. 



The number of questions "put to the soil 

 and the plant" in a given plat experiment has 

 usually been far too large. For example, the 

 customary rotation-fertilizer experiment has 

 often covered practically the whole range of 

 soil fertility and plant nutrition. This wide 

 range has limited the amount of replication 

 jDracticable, and it has failed to refiect the 

 discrimination in gathering data and the 

 simplification of the problem dictated by the 

 method of science. 



Such experiments have relied quite largely 

 on what the field results themselves were inter- 

 preted to show, primarily the crop returns. 

 True, most of the later experiments have em- 

 bodied plans for chemical, bacteriological, and 

 other laboratory studies, but only to a limited 

 extent have these been developed with the 

 progress of the work so as to shed new light. 

 The chemical studies have often become of a 

 routine nature — analyses of the crops and of 

 the soils at stated intervals, and the bacteri- 

 ological studies by the technique developed 



