180 



STATE BOARD OF AGRICULTURE. 



From the appearance of the precipitates and from the fact that fairly 

 good agreement was obtained with pnre quartz sand it seems probable 

 that the error is due to the humus in the soil. 



NITRATES IN COMMERCIAL FERTILIZERS. 



With fertilizers much better results were obtained. The following 

 table gives some of the results with various samples, some of which were 

 quite pure sodium nitrate while others were mixed fertilizers. Pre- 

 liminary tests were made with diphenylamine. Five to ten grams of 

 the sample, according to the apparent amount of nitrate present, were 

 weighed into 500 c. c. flasks, dissolved, and made up to volume. Ali- 

 quots were taken and analyzed as described above except that concentra- 

 tion was usually unnecessary and in some cases the sample was diluted 

 to 75-100 e. c. ' 



Sample number. 



2839. 



2932. 



2727. 



2810. 



2873. 



2830. 



2798. 



2751. 



2711. 



3717. 



2890. 



"Nitron." 

 Method. 



