212 



AGRICULTURAL EXPERIMENT STATION. 



2. 500 grams Dissolved Bone Black. 



60 " Sodium Nitrate. 

 100 " Dried Blood. 



3. 500 " Dissolved Bone Black. 



60 " Sodium Nitrate. 

 100 " Dried Blood. 



60 " Ferrous Sulphate. 

 Samples 4, 5 and 6 were prepared as 1, 2 and 3 respectivel3', 

 except that dissolved South Carolina Rock was substituted for the 

 Bone Black. The superphosphates, after being finely ground and 

 well mixed, were placed in wide-mouthed bottles, loosely stoppered 

 and allowed to stand on the floor in one corner of the laborator3\ 

 From time to time the nitric acid and total nitrogen were determined 

 in these sample*. In order that the results might be compared, 

 the moisture was also determined and all the results reduced to a 

 water-free basis. 



The first determinations of total nitrogen were made by the abso- 

 lute method ; the others by the modified Kjeldahl method. The 

 results are given below. 





August 



, 1887. 



Octobei 



, 1887 



December, 1887 



Julj, 



1888. 



Dec'r, 



1888. 





c 



— O 



6 



.s s 



c 



Ml 



— c 



II 



6 



^5 



c 

 a> 



— c 



Is 



.2 - 



t5S 



a 

 o 



— o 



Is 



6 



ss 



o 



bo 



Iz 



1 



3.53 



3.18 



3.42 



3.09 



3.18 



3.24 



3.13 



3.07 



3.07 



2 



3.60 



1.79 



3.50 



1.70 



3.51 



1.72 



3.64 



1.71 



3.60 



3 



3.38 



1.62 



3.46 



1.65 



3. 2d 



- 



3.26 



1.54 



3.12 



4 



3.06 



- 



- 



3.05 



3.25 



- 



2.94 



2.88 



2.89 



5 



3.43 



1.66 



3.45 



1.70 



3.14 



1.64 



3.31 



1.68 



3.26 



6 



3.28 



1.47 



- 



1.48 



2.91 



1.49 



2.97 



1.48 



3.06 



The amount of moisture present varied greatly from time to 

 to time, and the apparent fluctuations in the amount of nitrogen was 

 undoubtedly due in part to errors in reducing the results to a 

 water-free basis. 



Four months before the last determinations were made the 

 samples were wet almost to a paste. Although the conditions were 



