XV. ABSTRACT OF PROCEEDINGS 
use in directly inoculating soil or seed. Preparations of 
Nobbe, Hiltner, Moore. None of these can claim anything 
like certainty in their action and they have not so far 
advanced beyond the experimental stage nor established 
themselves as part of ordinary farm practice. 
The problem of artificially fixing atmospheric nitrogen 
economically in a form suitable for the nutrition of plants 
was next discussed. Calcium cyanamide, prepared by pass- 
ing nitrogen over calcium carbide at a white heat, has been 
found to possess manurial value, due to the formation of 
ammonia in contact with moisture. Hxperiments so far 
indicate that there is nothing to show that it hasa higher 
manurial value than ammonium sulphate with which it 
cannot at present compete in price. There are also certain 
disadvantages in its use, depending on the difficulty of 
mixing with other manures, therisk of injuring germin- 
ation etc. More promising methods appear to be in the 
direct union of the oxygen and nitrogen in the air by 
means of the electric arc. Among processes which have 
been tried on the commercial scale with some success are 
Bradley and Lovejoy’s, which was in operation at Niagara 
till 1904. The most successful process up to the present is 
that of Birkeland and Hyde which is now being carried 
out on an enormous scale in Norway. In this process air 
is sparked in a specially constructed electric furnace by 
means of an arc spread out into a fan by means of electro- 
magnets. The air thus sparked is passed through towers 
charged with milk of lime, and the nitrite formed con- 
verted into calcium nitrate by treatment with nitric acid. 
The product is put on the market either in this form or 
is converted into a non-hygroscopic basic nitrate by 
calcining it with lime (Messel’s process). Calcium nitrate 
appears to be just as effective as a manure as sodium 
nitrate and the question of the future of the industry 
becomes one of cheapening the unit cost of the current. 
