5 
62 Colorado Experiment Station 
phosphoric acid, that between incineration at ‘‘redness” and the acetate 
miethod to be equal to 35.0 percent of the P2 Os. Without any knowl¬ 
edge of the results obtained by these authors, I found that it is prac¬ 
tically impossible to obtain correct results in making this determination 
by igniting at a very low temperature, in a partially covered crucible 
over a very (low Bunsen flame- I made a series of 38 determinations 
by ignition, and by dissolving in concentrated nitric acid with the addi¬ 
tion of a sufficient quantity of magnesic oxide and subsequent ignition, 
and found the differences ranging from lo.o to 37.0 percent of the 
phosphorus present. The determination of phosphorus in straw by 
ignition is still more difficult, owing to the excess of silica and carbon 
which, at a comparatively low temperature, may cause the volatilization 
of practically the whole of the phosphorus. 
Leavitt and LeClerc think that the loss of phosphorus in making ^ 
the determination of total ash in grain may be neglected.* According 
to our observations, the method of charring and extracting with water 
is unsatisfactory, especially if we are to consider differences of one 
or two tenths, or even hundredths of i percent, as significant of the 
effects of fertilizers or weather conditions. The results given in the 
preceding tables were obtained by this method, and we justify the use 
of these results on the supposition that, the method having been worked 
in a uniform manner, the results have an error, but this is common to 
all of them and in the same direction. The ash, or mineral-constitu¬ 
ents, given in the table under the latter caption, were not determined 
by preparing an ash by the usual incineration. The air-dried wheat 
was dissolved in concentrated nitric acid and subsequently ignited, but 
this is not the place for these technical details. 
The standards adopted for reference are averages given by Leach 
in his work on “Food Inspection and Analysis”. Reference will also 
be made to Hungarian wheats given bv Kosutany. 
* Loc. Cit. 
