APPLICATION OF SCIENCE TO PLANT CULTURE. 85 



Three years ago, the " American Chemical Journal," contained 

 some accounts of some experiments by mj^self. Peas were grown 

 in sand supplied with solutions containing the necessary ingrecli- 

 ents of soil food, mineral matters in abundance, and nitrogen in 

 various quantities, the soil being a mere mechanical medium. 

 The comparisons were made between the quantities of nitrogen at 

 the beginning and at the end of the experiment. If the quantity 

 in the plants added to that remaining in the nutritive solution at 

 the end of the period of growth should be found to exceed that 

 supplied at the beginning in the nutritive solution and the seed, 

 this excess, of course, must come from somewhere, and the air 

 was the only possible source. As a matter of fact, a large excess 

 was found ; and this amount of atmospheric nitrogen was larger 

 in proportion as the plants were better fed. The experiments 

 were carried on during two successive seasons and those of the 

 second season very strikingly confirmed those of the first. As 

 these results were decidedly in conflict with those obtained by 

 Boussingault, Lawes and Gilbert, and others, it was, of course, 

 natural to seek an explanation of the disparity in the results. 



A 3'ear and a half ago, accounts of some experiments made to 

 get light upon this question were published in the same journal. 

 The outcome was that when plants are grown as the}' ordinarily 

 are in experiments of this kind, there may be a loss of nitrogen — 

 that is to say, some of the nitrogen supplied in the nutritive sol- 

 ution and in the seed, may escape into the air, and of course all 

 that goes off in this way diminishes by so much the quantity 

 obtained at the end of the experiments, and thus reduces the 

 apparent gain from the air. In some of my own experiments, 

 the plants, when ripe, contained no more nitrogen than had been 

 supplied in the nutritive solution and the seeds ; but the circum- 

 stances were such as to make it highly probable that some nitro- 

 gen escaped. Now if these particular experiments had been taken 

 as a test of the question whether plants get any nitrogen from the 

 air or not, it would have been negative. 



I may, perhaps, be permitted to read the following conclusions 

 drawn from the quantity of facts observed in these experiments : 



"The experimental testimony regarding the acquisition of 

 atmospheric nitrogen by plants is conflicting. But the evidence 

 against.it which comes from the laboratory and greenhouse is 

 based upon experiments whose conditions were more or less 



