TRODUCE FROM GUANO AND BONE-DUST. 



279 



became smaller in each follo-\ving year ; in the first year 

 the crop from the bone-dust was smaller, but in the suc- 

 ceeding years the increase was most remarkable. 



The 411 lbs. guano contained 53, and the total produce 

 271 lbs. of nitrogen, or very nearly five times more. 

 The bone-dust contained 37 lbs. of nitrogen, whereas in the 

 total produce there were 342 lbs., or nearly nine times more. 

 The bone-dust gave in the crops altogether 71 lbs. of 

 nitrogen more than the guano. Between the quantity of 

 nitrogen in the manure and the amount of the crops 

 reaped, there is, therefore, no connection Avhatever. 



In the Saxon experiments, the plots manured with 

 bone-dust gave the following results : — 



Manuring with hone dust. 



