332 - TIMHERI. 
Rothamstead, St. Alban’s, 
June 25th, 1897. 
Dear Sir,—I thank you very much for your reports 
upon the Sugar Cane, which are highly valuable as well 
as of great interest to myself. Many years ago, I was 
anxious to establish by dire€&t experiment whether all 
the plants of the natural order Graminez derived all 
their nitrogen from nitric acid; of course my climate 
confined my experiments to grapes, wheat, barley and 
oats. . 
I was most anxious to carry out similar experiments 
on Sugar Cane and Rice, and for this purpose J acquired 
some land growing Sugar Cane in Queensland, but the 
dispute in relation to black labour prevented me from 
taking up these investigations. Your results are quite 
conclusive in regard to the Sugar Cane, and it is quite 
clear to me that all the Graminaceous family derive their 
nitrogen from nitric acid in the soil, and it is probable 
that this is the only source of their nitrogen, at all 
events in our experiments the measure of their growth 
is limited to the quantity of nitric acid which they 
can obtain from the soil. 
The great difficulty to contend with in the application 
of ammonia and nitrates to the cane arises from the 
difficulty of keeping the land free from weeds; to turn 
nitric acid into organic nitrogen to become at some 
future time nitric acid again is a serious loss, and there 
can be no doubt that an unmanured wheat which is now 
growing its 54th crop in succession, and which still grows 
a crop equal to or perhaps more than the average 
crop of the world, is due to the faét that we keep 
the land free from weeds. 
