12 



was put on in two instalments. There was no drainage to the pots. The plants 

 were watered with filtered Nile water. Four plants were allowed to remain 

 in each pot. 



The two organic manures have obviously done but little good, probably owing 

 to the very short duration of the experiment and partly owing to the fact that 

 with so restricted a root system the soil had to be kept very wet or flagging took 

 place. It is unfair therefore to compare these with the " artificials. " 



Taking the increase brought about by nitrate of soda (average) as 100, we 

 get the following : 



Nitrate of soda 100 



Sulphate of ammonia 92 



Cyanamide (average) 59 



Nitrate of lime 104 



Nitrate of ammonia 98 



Cyanamide therefore is not so efficient as the nitrates under the conditions 

 of this experiment, while ammoniacal nitrogen appears to have an equal value. 

 The slowness of action of the organic manures appears to be due to a failure to 

 convert the organic nitrogen into ammonia rather than a failure to change the 

 latter to nitrate. This is shown by the fact that ammonium sulphate gives a 

 good result. The time factor is no doubt, as mentioned above, of importance in 

 this connection. 



The results obtained accord very well with those made both in pots and the 

 field in Germany. Nitrate of lime has almost invariably proved more efficient 

 than nitrate of soda. In this experiment the plants receiving nitrate of lime 

 appeared especially robust. The action of nitrate of ammonia is interesting; 



