HISTORICAL AND INTRODUCTORY 

 TABLE I. STATISTICS OF A ROTATION. BOUSSINGAULT (46). 



1000 kilograms per hectare = 16 cwt. per acre. 



TABLE II. NITROGEN STATISIICS OF VARIOUS ROTATIONS. 

 BOUSSINGAULT (46). 



1 Catch crop, i.e. taken in autumn after the wheat. 



2 This crop does not belong to the leguminosae, but it is possible that the 

 nitrogen came from the soil, and that impoverishment was going on. 



