79 



WEIR, W. 



1915. The effect of removing the soluble humus from a soil on its produc- 

 tiveness. /. Agr. Set., y. 7, pp. 246-253. 



WISE, L. E., and WALTERS, E. H. 



1917. Isolation of cyanuric acid from soil. J. Agr. Res., v. 10, pp. 85-91. 



WOHLER, F. 



1828. Ueher kiinstliche Bildung des Harnstoffs. Poggcndorff's Ann. Phys. 

 . Chem., Bd. 12, pp. 253-256. 



