NITEOGENOUS MANUEES. 251 



then obtained which should only be employed as manure with 

 great precautions. Some years ago Maercker analysed a product 

 of this kind, under the name of crude ammonia. He found the- 

 following products : — 



TABLE LXX.— ANALYSIS OF SPENT OXIDE FEOM GAS WORKS. 



Moisture .... 



Sulphate of ammonia 



Insoluble nitrogen compounds 



Ferrous sulphate . 



Sulphur . . . • 



Cyanogen compounds 



Ferrous oxide and ferrous sulphide 



Lime organic matter 



Sand, clay, etc. 



Per cent. 



8-7 

 17-8 = 5-3 per cent nitrogen. 



5-4 = 1-8 

 15-6 

 10-7 



1-2 

 22-3 

 14-8 



3-0 



100-0 containing 7-1 per cent N. 



Amongst these compounds the sulphate of ammonia is the only 

 fertilizing material; the insoluble nitrogenous compounds, the 

 sulphur, the lime, the sand, the clay, are inert materials ; whilst 

 the ferrous sulphate, the sulphide of iron, and the cyanogen com- 

 pounds, are plant poisons. These substances should not be em- 

 ployed as manure under any pretext. ^ 



Another crude ammonia of this nature exceedingly dangerous, 

 and also from an English source, and put on the market under the 

 name of brown sulphate of ammonia, was analysed by C. Schuman.. 

 This product contained : — 



Water 



Per cent. 

 4-86 



Sulphate of ammonia . . • 14-87 = ^ 3-15 per cent nitrogen. 

 Ehodanate of ammonia . . 73-94 - 27-24 ,, „ 



Sand 6-23 



99-90 with 30-39 per cent N. 



The rhodanate ^ammonium sulphocyanide] contained therein is 

 exceedingly poisonous to plants, and before using it, it is necessary 

 to ascertain if it is exempt from this body. 



The departmental laboratory of Chalons-sur-Marne analysed m 

 1907 a somewhat large number of crude ammonias from different 

 sources. The composition of some of the samples examined is given 

 in the following table : — 



1 Green vitriol has been used as a manure for stimulating etiolated plants 

 for nearly a century. — Tr. 



