230 



KErcRT— 1876. 



amount than last year ; this is equivalent to SO'Si per cent, of that received 

 in the sewage. 



The Table shows that 139 lbs. of nitrogen were recovered per acre over the 

 aggregate acreage under crop during the year, viz. 147-87 acres ; it will, 

 however, be more correct and of greater practical utility to show the amount 

 of nitrogen recovered in the crops per acre of the fai'm under crop, viz. 

 108-44 acres, during the past five years. 



In the following Table the amount of nitrogen applied to the farm in the 

 Bewage and that recovered in the crops is shown for each of the last five 

 years ; and it appears that the amount of nitrogen recovered in the crops 

 during the whole period is equal to 32-88 per cent, of the amount applied in 

 the sewage, and that the amount recovered per acre of the farm under crop 

 averaged 182 lbs. 



It will be observed that the small amount of nitrogen recovered per aero 

 during the year 1872-73 was compensated for by the unusually large amount 

 recovered in 1873-74, which latter was due to the fact that certain crops 

 taken off the ground in 1873-74 had derived the greater part of their 

 nitrogen from the sewage of the previous year. 



The value of these results is much enlarged by the fact that they have been 

 obtained by a series of observations and experiments extending over a period 

 of five years, so that the effect of the inevitable annual variations, of which 

 a notable example is furnished by the first three years, is got rid of. 



* As the Ecwaga was not gauged in the year 1873-74, tl^o amount of nitrogen applied 

 is tateh as the mean of that applied in the years 1872-73 and 1874-75. 



