ON 



THE SOURCES OF 



THE 



NITROGEN OF VEGETATION; 



WITH SPECIAL REFERENCE TO THE QUESTION WHETHER PLANTS 

 ASSIMILATE FREE OR UNCOMBINED NITROGEN. 



LIBRARY 

 YORK 



. M1CAL 

 GARDEN 



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., F.C.S. 



From the PHILOSOPHICAL TEANSACTIONS.— Pakt II. 1861. 



LONDON: 



PRINTED BY TAYLOR AND FKANCIS, KED LION COURT, FLEET STREET. 



1862. 



