ON 



THE SOURCES OF 



THE 



NITROGEN OF VEGETATION; 



WITH SPECIAL REFERENCE TO THE QUESTION WHETHER PLANTS 

 ASSIMILATE FREE OR UNCOMBINED NITROGEN. 



BY 



JOHN BENNET LAWES, F.R.S., F.C.S., 

 JOSEPH HENRY GILBERT, Ph.D., F.R.S., F.C.S., 



AND 



EVAN PUGH, Ph.D., ECS. 



From the PHILOSOPHICAL TEANSACTIONS.— Part II. 1861. 



LONDON: 



PRINTED BY TAYLOR AND FRANCIS, RED LION COURT, FLEET STREET. 



1862. 



• 



