APPENDIX. 



NEW NITEOGENOUS MANUEES. 



The manurial sources of nitrogen have during the 

 last few years been supplemented by two methods of 

 bringing the nitrogen gas of the atmosphere into 

 combination, and the products are now becoming 

 factors of importance in the fertilizer market. Speak- ^ 

 ing broadly, there are two ways of bringing nitrogen 

 into combination : firstly, at extremely high tempera- 

 tures, such as are attained in the electric arc or sparks, 

 nitrogen will combine with the oxygen also in the air 

 to produce oxides which yield nitric acid on absorption 

 with water ; secondly, nitrogen will combine with a 

 few metals and allied bodies to yield compounds which 

 under the action of water give rise to ammonia. It 

 has been this latter method that has first been deve- 

 loped on a commercial scale by Frank and Caro, of 

 Berlin ; they started with the calcium carbide which 

 is so well known as a source of acetylene gas for 

 illumination, and found that it would combine with 

 nitrogen gas at quite moderate temperatures. The 

 resulting product is now on the market as nitrolim, 

 or calcium cyanamide, and large factories have been 

 established for its production on a vast scale in Italy, 

 Norway, Savoy, America, &c., where cheap water- 

 power for the electrical manufacture of calcium 

 carbide is available. 



