536 
Journal of Agricultural Research 
Vol. XXVIII, No. 6 
minutes and a larger volume of distillate was collected. There were not very 
large differences found by the modified Strowd method in the percentages of 
nitrate recovered from the filtered and unfiltered solutions of tobacco. The 
advantage is slightly in favor of the filtered solution. Good results were obtained 
in either case, and this would indicate that it is not necessary to filter in order 
to make a satisfactory determination. 
The modified Strowd and Ulsch-Street methods were found to be very satis¬ 
factory for commercial nitrates, but the latter method gave much lower results 
on the other samples except when the modification of it referred to above was 
employed, in which event more satisfactory results were obtained. 
COMPARISON OF THE MODIFIED STROWD, ULSCH-STREET, AND OFFICIAL 
MAGNESIUM OXID METHODS FOR AMMONIACAL NITROGEN IN FER¬ 
TILIZERS. 
In this work the results obtained in the control determinations by the modified 
Strowd method on the fertilizer samples were compared with those found for 
ammoniacal nitrogen by the official magnesium oxid method. A more limited 
comparison was also made in the same manner by the Ulsch-Street method. 
(See Table VI.) 
Table VI.— Comparison of the modified Strowd , Ulsch-Street and official magnesium 
oxid methods for ammoniacal nitrogen in fertilizers 
Number 
Official 
MgO 
method 
Modified Strowd 
method 
Ulsch-Street method 
Filtered 
Not filtered 
Filtered 
Not filtered 
63595 ..... 
1. 12 
b 1. 14 
Per cent 
1. 06 
1. 11 
1. 11 
1. 02 
Per cent 
1. 25 
1. 26 
1. 26 
Per cent 
Per cent 
1. 33 
Average_ 
1. 13 
1. 08 
1. 26 
63601_ 
0. 28 
6 0. 21 
. 29 
. 31 
. 23 
. 50 
. 53 
. 43 
c 0.32 
c . 44 
. 45 
. 48 
Average_ 
63605_ 
0. 25 
. 28 
. 49 
. 46 
0. 42 
6 0. 37 
. 36 
. 35 
. 35 
. 30 
. 68 
. 72 
. 64 
. 75 
Average_ 
0. 40 
. 34 
. 68 
63607 - __ 
1. 17 
6 1. 24 
1. 21 
1. 20 
1. 25 
1. 17 
1. 35 
1. 33 
1. 29 
1. 37 
Average ___ 
1. 21 
1. 21 
1. 32 
® Control computed as ammoniacal nitrogen. 
& Results obtained by this method in the fertilizer department. 
c Volume of solution was 350 cc. and collected 150 cc. of distillate. In the official method the prescribed 
volume is less than 150 cc. and only 100 cc. of distillate could be obtained. The solution of acid and iron 
was boiled for 10 minutes instead of 5 minutes as recommended. 
