386 



SCIENCE. 



[N. S. Vol. XXIV. No. 613. 



fields to cultivate, but do not fully serve 

 when the rich stores of fertility in our 

 fields have been, in part, exhausted. 



In the next place, the conditions that 

 existed here in the earlier history of our 

 country, were not such as to demand on 

 the part of the tiller of the soil, or farmer, 

 a knowledge of those principles which 

 would enable him to utilize to the best ad- 

 vantage soil fertility, and when the time 

 came (as it has now for a large portion of 

 our country), when knowledge of prin- 

 ciples became a necessity, in order that 

 farming on these areas might be made 

 profitable, the first duty of the chemist 

 was to rather demonstrate the usefulness 

 of an application of the chemical knowl- 

 edge already available. That is, the chem- 

 ist became a teacher, rather than an investi- 

 gator, and the results of his work have 

 been altogether good. There is now a wide 

 knowledge of underlying principles, among 

 the more intelligent of our farmers, 

 mainly, however, in respect to what we 

 now know of the relationship between the 

 soil, the plant and the animal. The 

 farmer has been taught that the soil is 

 potentially fertile, in proportion to the 

 amount of nitrogen, phosphorus and 

 potassium that it contains; that the re- 

 moval of crops, resulting in the carrying 

 away of these essential elements, will ulti- 

 mately exhaust his soil to such an extent 

 as to make their further growth unprofit- 

 able, without the addition of the other ele- 

 ments. He has, also, learned from the 

 chemist that a judicious utilization of 

 crops upon the farm, and a careful hand- 

 ling and use of waste products, will extend 

 the period of profitable cropping. The 

 chemists of the country have, also, ren- 

 dered incalculable service in the study of 

 those substances which carry these elements 

 of fertility, and which are capable of serv- 

 ing as food for plants, and thus developing 



in a remarkable degree the farmer's 

 ability to use them in the manufacture of 

 crops, in the sense that they may be con- 

 verted into products of high commercial 

 value. The chemists have, also, promoted 

 the intelligent purchase and use of com- 

 mercial fertilizers, by the development and 

 improvement of methods of chemical anal- 

 ysis, which enable them to accurately de- 

 termine the various chemical forms. They 

 have, also, by means of field experimsents, 

 demonstrated their comparative influence 

 in meeting soil and crop requirements, and 

 are thus able to give safe advice as to the 

 value of the various supplies. 



Still, with all this, and with the utiliza- 

 tion of the products in the best manner, 

 we are confronted with the fact that we 

 have but little more definite knowledge of 

 the soil and the principles involved in its 

 treatment than we ha.d sixty years ago. 

 Fertility is not nitrogen, phosphorus and 

 potassium alone, though the potential value 

 of any field, or state or country, from the 

 agricultural standpoint, is measured by 

 these constituent elements in its soil, yet 

 it has been demonstrated that soils which 

 contain an abundance of these elements, 

 and which are potentially capable of pro- 

 ducing crops for centuries perhaps, are not 

 capable of producing profitable crops with- 

 out the addition of further amounts of 

 these constituents. The chemical investi- 

 gator is, therefore, obliged to take into 

 consideration other facts than this. He 

 must, if he would cover the whole field, 

 know something of geology, of botany, of 

 physics, of biology, of bacteriology and of 

 the other natural sciences, because chem- 

 istry alone is not capable of fully com- 

 passing the problem, thus the opportunity 

 for specializing in any branch has been 

 very great, and it is because of the broad- 

 ness of the subject, and the opportunity, 

 as already pointed out, and the necessity. 



