The: Fixation oe Nitrogen. 49 
soluble in watei and reacted strongly for nitric acid. The reaction 
depended on in all cases is that with ferrous sulfate and sulfuric 
acid. If a few grams of soil, from 10 to 25, will not give with 20 
to. 30 cc. of water, a solution which will give a decided reaction 
with these reagents it scarcely belongs to the class of soils, with 
which we are concerned. The owner put in a short drain to protect 
a poi tion of his orchard which he feared might be suffering on 
account of excessive water. This drain never collected much 
water, and was entirely dry on my next visit. The trees in this 
Part of the orchard.were at this time, July 23, 1910, burning badly. 
We had in this orchard an excellent opportunity to compare 
the nitre burning with spray burning. The two differ in the point 
of attack, the nitre beginning at the apex and the margins of the 
leaf and very rarely, if ever, on the inner parts of the blade, and 
the color is lighter. 
This is a piece of sloping* ground and is at the base of a hill. 
^ here is no irrigation above it that I can recall. A little to the 
south and west of this orchard on the roadside is one of the most 
remaikable spots of this character that I have met with, not except¬ 
ing the first one that I recognized and which is represented by 
Analysis No. 1, Bulletin 155, page 7. 
These spots, for there are a number of them, are scarcely worse 
than some of the land in the orchard where the trees were burning 
very badly. This soil is actually kept moist by the deliquescent 
nature of the salts formed. A sample from such a spot in the 
orchard gave 12.10 percent soluble in water and the notes state 
that this residue had to be dried at iio° 111 the air-bath for 12 
hours. Another sample gave 12.560 percent soluble in water, and 
this extract bears a special label “had to dry at 115 0 for 20 hours 
to get dry enough to put into the bottle.” I am giving these details 
perhaps ad nauseam, but I find that they appear so strange to per¬ 
sons who have never met with such facts themselves as to seem 
wholly incredible. The analyses of these samples may be their own 
witnesses. 
