U. S. DEPARTMENT OF AGRICULTURE. 



OFFICE OF EXPERIMENT STATIONS— BULLETIN NO. 149. 



A. C. TRUE, Director. 



lES OF THE 



BY 



C. D. WOODS, 



Director, Mnine Agruniltnml Erperimeni Station, 



AND 



E. R. jSIANSFIELD, 



Assistant Chemist, Maine Agricultural Experimait Station. 



WASHINOTON: 



GOVERNMENT PRINTING OFFICE. 



1 4 . 



