Field Experiments on the Fixation of Free Nitrogen. G57 
commencement of the tentative experiment with the cereals, 
the amount of available nitrogen in the soil must have been 
exceedingly small. 
We have thus, from beginning to end, collected a quantity 
of nitrogen in the three crops, beans, clover, and clover, equal to 
376 lb. per acre, or equivalent to more than one ton of nitrate of 
soda per acre, over a period of three years. This is equal to 
750. lb. of nitrate of soda per acre per annum. In addition, the 
amount of nitrogen contained in 8 tons of potatoes per acre, and 
acquired from the underground accumulation of nitrogen, may 
be assumed to be 59 lb. Of course, it is not by this experiment 
scientifically proved that the nitrogen was derived from the 
atmosphere, as all soils contain a very large quantity of inert 
nitrogen in some form or other. 
On the other hand, these experiments certainly go to show 
that the leguminous plants, beans and clover, thrive well on their 
own account in a soil very deficient in nitric nitrogen, but well 
sujDplied with mineral food, and that they are capable of accumu- 
lating nitrogen in the soil itself, and by their roots capable of 
supporting an after-crop requiring so large a supply of nitrogen 
as potatoes. 
In continuance of the experiment I have, in the autumn of 
1892, sown on plots. Nos. 23 and 24, Eivett wheat, without 
any additional manure of any kind, in order that I may ascertain 
if there is a still further quantity of assimilable nitrogen derived 
from the previous bean and clover crops and not utilised by the 
potatoes. From my actual results this year on farm land run- 
ning in similar grooves, I am inclined to think there will be 
enough for a moderate crop. 
I take this opportunity of saying that I have now in hand 
some 450 acres of arable land which is being gradually brought 
under a systematic rotation, beginning with a two-years legu- 
minous crop, followed by two years of nitrogen-consuming 
crops. So far the results correspond very well with expectations ; 
but two or three seasons must elapse before a clear balance- 
sheet and sound matter for discussion can be worked out in a 
profitable form. The 435 lb. of nitrogen per acre, carried from a 
soil in three kinds of crops, which soil had only shown a capacity 
for producing minimum crops of barley and oats, containing on an 
average, grain and straw together, only 12 lb. of nitrogen, is a 
very notable fact, whatever may be its practical value ; and, had 
it not been for the new light as to the sources of the nitrogen 
of papilionaceous crops, would have thrown us back upon sub- 
soil nitrogen, and upon ammonia or nitric acid from the atmo- 
sphere, to account for its accumulation. James Masox. 
