PREFACE. 



This volume is intended to be a review of the present knowl- 

 edge of Cyanamid, particularly its chemical and agricultural 

 properties. Its purpose is to render some assistance to the 

 investigator who has neither the time nor the library facilities 

 to enable him to make a thorough study, yet who wishes to 

 broaden his knowledge of Cyanamid. Most of the important 

 literature on this subject is written in foreign languages, and 

 many valuable papers occur in journals not found in the ordi- 

 nary agricultural or chemical library. Moreover, the opinions 

 that have been expressed on almost every phase of the be- 

 havior of Cyanamid are so diversified and frequently so deeply 

 buried in controversy that the casual reader is at a loss to 

 know what to accept as generally established facts. It is hoped 

 that the present volume will give to the reader a consistent ex- 

 planation of Cyanamid that will form the starting point for the 

 acquisition of further knowledge. 



In order to arrive at an understanding of the principles 

 underlying particular phenomena it is necessary to adopt at the 

 beginning of an investigation some sort of working hypothesis 

 that will account for the observed facts. Every further fact 

 that is acquired must then verify the original hypothesis or the 

 latter must be modified to fit the facts. The constant re- 

 modeling of ideas to agree with observed facts finally leads to a 

 system of knowledge, in which every fact explains to a cer- 

 tain extent every other fact, and in no case contradicts any of 

 them. Such a system of knowledge of Cyanamid, it is be- 

 lieved, is now at hand. The pure chemistry of Cyanamid, its 

 physico-chemical action in the soil, its biological behavior, and 

 its agricultural properties, as presented in this volume, are con- 

 sistent with each other. Such consistency is believed to induce 

 confidence in the validity of the views expressed. Further 

 experiments may make necessary some slight changes, but the 

 general scheme of the properties of Cyanamid may now be con- 

 sidered as quite definitely established. 



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