73 
to a sufficiently high temperature. The Calcium Carbide is first 
produced in the usual manner by heating lime and coke to a tem- 
perature of 2500 degrees Centigrade in electric furnaces of the 
resistance type. The carbide is then heated' in retorts, and at 
1 100 degrees (C), atmospheric nitrogen is introduced and ab- 
sorbed, the new compound being known as Calcium Cyanamide. 
The first plant erected for the manufacture of Calcium Cyana- 
mide was at Piano d'Orta, Italy, in 1905. In this factory were 
installed six furnaces, each with five retorts for the absorption 
of Nitrogen by the Carbide. Each retort works off three charges 
daily, consisting of 100 kilograms (2200 lbs.). The absorption 
of Nitrogen by the Carbide increases the weight materially, and 
from each charge 125 kilograms (275 lbs.) of Calcium Cyana- 
mide is obtained. The plant has, therefore, an annual capacity 
for the conversion of 3000 tons of carbide into 3750 tons of 
Cyanamide. This factory is operated by water power, supplied 
by an independent company. The generating station, where a 
head of 90 feet, supplying 8400 h. p., is available, is more than 
six miles from the cyanamide plant, to which the power is trans- 
mitted at 6000 volts. The factory has proved* so successful that 
already an extension to an annual 10,000 tons capacity is in pro- 
gress, and other similar plants are projected throughout the 
country. 
In France, the Societe Franchise des Produits Azotes is al- 
ready in operation and another in Savoy has an annual output 
°f 375° tons. In Germany and England the Frank and Caro 
process is also being actively operated, and in the United States the 
American Cyanamide Company of Alabama will have an annual 
capacity of 20,000 tons. 
The method is already being improved and the chemist, Pol- 
zeniusz, has discovered an important modification in the manu- 
facture of Cyanamide. This is brought about by the addition of 
Fluor-spar to the carbide which facilitates the absorption of 
Nitrogen at the comparatively low temperature of 400 degrees 
(C.) and, moreover, produces a product which does not so read- 
ily become moist. The market price of Cyanamide is at present 
regulated by the price of the two competing artificial manures, 
ammonium sulphate and nitrate of soda. Its actual cost of pro- 
duction has been found in Germany to average about $40 per 
ton, which has been marketed at a little over $50. This has 
been achieved in cases where cheap water power was available, 
but as the process improves, the rival fertilizers, will without 
doubt, be eventually driven from the market by this and similar 
new products. 
CALCIUM NITRATE. 
Another noteworthy new artificial fertilizer. Calcium Nitrate, is 
manufactured by the Birkeland and Eyde process, at Notodden, 
